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Chapter 2: Review on the Precambrian Stratigraphy of the Singhbhum Craton

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Chapter 2

Review on the Precambrian Stratigraphy of the

Singhbhum Craton

2.1 Introduction

The Indian Peninsular Shield is a composite collage of several Archean cratonic nuclei,

bounded by major mobile belts, along with cover rocks of Proterozoic and Phanerozoic

ages that were accumulated in intracratonic depressions and rifts (Radhakrishna and Naqvi,

1986). These cratonic blocks are flanked by fold belts, with or without discernible suture

or shear zones and have distinct structural, lithological and geochemical characteristics

with distinctive age range reflecting a major crustal development (Homes, 1955; Santosh

et al., 2009; Dharma Rao et al., 2011; Mohanty, 2011). The Indian shield is believed to

have been stabilized to its present configuration by ~2.1 to ~1.8 Ga through the

amalgamation of these Archaean cratonic nuclei which later resulted in granite-greenstone

terrains containing elements as old as ~3.4 Ga (Radhakrishna and Naqvi, 1986) and even

older 3.5 Ga (Mukhopadhyay et al., 2008). Five major Archaean cratonic nuclei, namely,

the Aravalli-Bundelkhand, East and West Dharwars, the Singhbhum, and the Bastar cratons

constitute the Precambrian continental crust of India (Naqvi, 2005). The Aravalli and the

Bundelkhand blocks constitute the north Indian shield, while, Dharwars, Bastar and the

Singhbhum blocks welded together along rift-valleys define the southern Indian shield. The

northern and southern Indian shields are sutured along the Satpura Mobile Belt, which is

redefined as the Central Indian Tectonic Zone (CITZ) (Acharyya, 1997; 2003; Yoshida et

al., 2001) (Fig. 2.1and 2.2). Among these cratonic blocks of Indian shield, the Singhbhum

craton (SC) of eastern India remained one of the geologically important craton for a variety

of academic and economic reasons. The present area of study lies in the southwestern

corner of the SC (Fig 2.3).

2.2 Litho-tectonic framework of the Singhbhum Craton

The Precambrian Singhbhum–North Orissa Province covers more than 50,000 sq km area

in eastern part of India lying in parts of Jharkhand and Odisha states bounded between

latitudes 210 00” N and 230 15’ N and longitudes 830 30’ E and 870 00 ’E and exposing a


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Fig. 2.2. Litho-tectonic Map of eastern India showing disposition of Archean cratonic blocks,

Proterozoic Mobile Belts, volcano-sedimentary and sedimentary basins and Deccan Trap (DT)

volcanics. Lineaments: Central India Tectonic Zone (CITZ), Narmoda-Son Lineament (NSL),

Central India Suture (CIS) and Krishna-Godavari Lineament (KGL). Archean cratonic blocks:

Singhbhum (SC), Bastar (Bas), Bundelkhand (Bund) and Dharwad cratons (DC).

Paleoproterozoic Mobile belts: Singhbhum Mobile Belt (SMB) to the north of SC, Mahakoshal

Belt (MB), Betul Belt (BB) along southern fringe of NSL, Amgaon Belt (AB) and Kotri Linear

Belt (KLB) of Bastar Craton. Mesoproterozoic belt: Sausar belt of central India. Proterozoic

cover sediments: Chhattisgarh (ChB), Vindhyan (VB), Indravati Basins (IB). Gondwana basins:

Damodar (DGB), Son-Mahanadi (SMGB), Pranhita-Godavari (PGB) and Satpura Basins (SGB)

(Modified after Meert et al.,2010).

Fig. 2.1. Simplified Tectonic Map

of India showing the disposition of

the major Archean cratonic nuclei

and the younger high grade

metamorphic mobile belts, crustal-

deep suture zones and rifts. Some

of the major Proterozoic and

Phanerozoic basins, large igneous

provinces are shown in the map

(compiled after, Reddy and Vijaya

Rao, 2000; Meert et al., 2010;

Dharma Rao et al., 2011).


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continuous rock records of crustal evolution from 3.7 Ga to 1.0Ga (Saha, 1994). Within

this province, a sub-province of triangular outline, called Singhbhum craton (SC) (also

known as Singhbhum-Orissa Craton, or Singhbhum-Orissa Iron Ore Craton or Eastern

Indian craton), was identified which is bounded by an arcuate copper-uranium bearing

crustal scale shear zone, called the Singhbhum Shear Zone (SSZ), in the north and is

Fig. 2.3. Geological map of Singhbhum craton showing distribution of major supracrustal units

(Map compiled after Mazumder, 1996). Note the distribution of the unclassified siliciclastic

rocks (bright yellow colour) in the southern and western margin of the Singhbhum Granite (SG)

batholith exposed from Mankarchua, Keonjhar and further north of Keonjhar in the north and

continues as detached outliers upto Daitari in the south.


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surrounded by the North Singhbhum Mobile Belt (NSMB) in the east, north and

northwestern sides with a closing age of the orogenic cycle at around 900Ma. SC is

bordered by Chhotanagpur Granite Gneiss Terrain (CGGT) towards farther north (Saha,

1994). The craton is further bordered by the Mahanadi graben to the west, the Son-Narmada

lineament to the west and northwestern boundary and the Indo-Gangetic alluvial plain in

the east (Saha, 1994; Meert, et al., 2010). Another crustal scale lineament, the WNW-ESE

trending Sukinda thrust zone, in the south defines the southern boundary of SC which

separates it from high grade (granulite facies) metamorphosed Eastern Ghat Mobile Belt

(EGMB) of granulite-charnockite-Khondalite association in the south (Saha, 1994,

Mazumder, 1996; Mukhopadhyay, 2001; Ghosh, et al, 2008) (Fig. 2.3).

The SC consists of five principal litho-tectonic components, viz. (i)

metasedimentaries of the Older Metamorphic Group (OMG) and the Older Metamorphic

Tonalite Gneiss (OMTG) intrusive into the OMG, (ii) massifs of Singhbhum Granite (SG)

(phases I, II and III), Bonai Granite, Kaptipada Granite and Pal Lahara Gneiss, (iii) Iron

Ore Group (IOG) dominantly composed of volcanic and Banded Iron Formation (BIF) at

the margins of the SG, (iv) greenstone belts dominantly comprising basic volcano-

sedimentary successions of Simlipal, Dhanjori, Dalma and several others with unresolved

stratigraphic relationships with three litho-tectonic components, and (v) craton-wide mafic

dyke swarm known as the Newer Dolerite (Acharyya, 1993; Bose, 1986; Naqvi and Rogers,

1987; Saha et al., 1988; Saha, 1994; Goswami et al., 1995; Mazumder, 1996; Mishra et al.,

1999, Misra et al., 2000; Misra, 2006; Mukhopadhyay, 2001; Mukhopadhyay et al.,2006,

2008; Sengupta et al., 1997; Sharma, 2009; Ghosh et al., 2010; Tait et al., 2010).

Towards further west the Precambrian crust of SC grew by accretion around the

nucleus constituted by the above mentioned five components (Mukhopadhyay, 2001). The

accretionary supracrustal rocks are represented by development of geosynclinal

successions like Darjing Group (Mahalik, 1987) Gangpur Group and some younger

intracratonic siliciclastic basins like Kolhan basin and Kunjar basin (Fig. 2.3).

The initiation of sediment deposition in SC has at least 3.5 Ga old records and a

metamorphic imprint of as old as ~3.2 Ga (Goswami et al., 1995; Mukhopadhyay et al.,

2008). Study of such old cratonic nuclei developed in every continent are extremely

important for understanding crustal evolution and geodynamic processes involved during

Archean time and that are primarily built up on the studies of the Archean granite-

greenstone terrains (de Wit and Ashwal, 1997; Condie, 2007). The SC also is no exception.


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2.3 An Overview on Stratigraphy of Singhbhum Craton

The Singhbhum cratonic block is a composite mosaic of Archean greenstone-granitoid and

the Proterozoic supracrustal successions with Proterozoic igneous intrusives and the Newer

dolerite dyke swarms (Acharyya, 1993; Saha, 1994; Mukhopadhyay, 2001, Meert, et al.,

2010). The oldest assemblages, the greenstone-granitoid associations, include two major

groups of Archean supracrustals: 1) the Older Metamorphic Group (OMG), consisting of

pelitic schist, arenite and para- and ortho-amphibolites, covering about 200 sq km area and

occur as smaller relics within the SG batholith, and 2) the Iron Ore Group (IOG)

supracrustals that occur as synformal keel-shaped Banded Iron Formation (BIF) bearing

mafic volcanic-dominated greenstone belts enclosed in the SG batholiths.

2.3.1 Older Metamorphic Group and Older Metamorphic Tonalite Gneiss

The OMG rocks are intruded by and subsequently co-folded with the oldest granitoid in the

SC (Saha, 1994; Goswami et al., 1995; Acharyya et al., 2010), namely, the Older

Metamorphic Tonalite Gneiss (OMTG), which contains enclaves of metasediment and

metavolcanic rocks of the OMG (Saha, 1994, see for reviews Mukhopadhyay, 2001; Misra,

2006). The OMG represents the earliest supracrustal rocks in the Singhbhum crustal

province, occurring as well-sorted sandstone and shale enclaves within the tonalitic

gneisses of OMTG. The pelitic schists of OMG are muscovite-biotite-(sillimanite) schist,

quartz-sericite schist grading into quartzite. Other units are para- (banded calc-gniesses and

hornblende schist) and ortho-(massive) amphibolites. Geochemically, OMG pelites are

slightly richer in SiO2, K2O,Cr, Ni, Cu and V and poorer in TiO2, CaO, Al2O3, Sr, Y, Li

and Zr with reference to the average pelite of Shaw (1954, 1956). Uranium tends to remain

constant with increasing SiO2 (Table 2.1).This is in consonance with the geochemical

characteristics of the Archean sediments (Taylor, 1979). Para-amphibolites are poorer in

TiO2 compared to OMG ortho-amphibolites and the latter exhibits a tholeiitic affinity

(Saha, 1994) (Table 2.1, Fig. 2.4a).Para-amphibolites show flat horizontal to gently sloping

REE patterns with more enriched LREE (x 100 chondrite) than HREE (x 50 chondrite)

(Fig. 2.5b) and are believed to be derived from low-K-tholeiitic type mafic rocks with

greater and variable concentration of REE-rich minerals (Saha, 1994).

The OMTG are dominantly tonalitic in nature with a few granodioritic to quartz-

dioritic to quartz monzo-dioritic composition (Fig.2.5a). OMTG are abnormally high in Mn

and Sr and low in Ti, V, Y, Ba, Rb and Zr and show moderate LREE and mild HREE


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enrichments (La/Yb = 41) with moderately steep sloping pattern without Eu-anomaly

(Eu/Eu* = 0.89-1.08) (Table 2.2) (Fig. 2.5b).A genetic relation between the OMTG and the

OMG-amphibolites was concluded where OMTG can be produced from partial melting

(~20%) of OMG-amphibolite magma. However, some components of OMTG was

suspected to contain elements of crustal rocks 150-450Ma older than OMG-amphibolite

(Sharma et al., 1994).

1 2 3 4

(n =

No. of

sample)

Average OMG

Pelitic schist

(n = 5)

Average medium grade

metapelite (Shaw,

1954, 1956)

Average OMG

Ortho-amphibolite

(n = 12)

Average OMG

Para-

amphibolite

(n = 10)

%

SiO2 65.43 61.54 52.49 53.56

TiO2 0.46 0.82 1.27 0.16

Al2O3 15.18 16.95 14.03 14.61

Fe2O3 3.96 -- 2.08 2.06

FeO 2.37 6.02 9.02 8.22

MnO 0.12 -- 0.19 0.45

MgO 2.76 2.52 8.05 6.60

CaO 1.17 1.76 9.07 9.70

Na2O 1.76 1.84 2.73 3.53

K2O 4.62 3.45 0.92 0.85

P2O5 0.04 -- 0.14 0.27

ppm

B 97 -- -- --

Ba 1034 -- 418.0 206.0

Be <10 -- -- --

Co 50 19.4 -- --

Cr 366 113 862.0 377.0

Cs 7 -- -- --

Cu 31.4 23.8 -- --

Ga 35 15.9 -- --

La 23.4 -- 15.4 22.8

Li 38 108 18.5 40.0

Ni 274 63.7 265.0 145.0

Pb 19.6 23.3 -- --

Rb 142.5 -- 17.0 27.0

Sc 20 11.9 -- --

Sr 104 731 227.0 213.0

Th 12.9 -- -- --

U 2.45 -- -- --

V 171 125 420.0 173.0

Y 226 37.9 -- --

Zr 106 213 163.0 141.0

Eu -- -- 1.07 1.7

Yb -- -- 1.90 3.4

Eu/Eu* -- -- 0.80 0.83

Table 2.1. Major and trace elemental analyses of Older Metamorphic Group pelitic schists,

ortho- and para-amphibolite rocks (after Saha et al., 1984; Saha et al., 1988). Note OMG pelites

are slightly richer in SiO2, K2O and poorer in TiO2, CaO and Al2O3 compared to the average

pelite of Shaw (1954) and richer in Cr, Ni, Cu and V and poorer in Sr, Y, Li and Zr. OMG ortho-

amphibolite analyses did not reflect any komatiitic affinity.

1 2 3 4

(n =

No. of

sample)

Average OMG

Pelitic schist

(n = 5)

Average medium grade

metapelite (Shaw,

1954, 1956)

Average OMG

Ortho-amphibolite

(n = 12)

Average OMG

Para-

amphibolite

(n = 10)

%

SiO2 65.43 61.54 52.49 53.56

TiO2 0.46 0.82 1.27 0.16

Al2O3 15.18 16.95 14.03 14.61

Fe2O3 3.96 -- 2.08 2.06

FeO 2.37 6.02 9.02 8.22

MnO 0.12 -- 0.19 0.45

MgO 2.76 2.52 8.05 6.60

CaO 1.17 1.76 9.07 9.70

Na2O 1.76 1.84 2.73 3.53

K2O 4.62 3.45 0.92 0.85

P2O5 0.04 -- 0.14 0.27

ppm

B 97 -- -- --

Ba 1034 -- 418.0 206.0

Be <10 -- -- --

Co 50 19.4 -- --

Cr 366 113 862.0 377.0

Cs 7 -- -- --

Cu 31.4 23.8 -- --

Ga 35 15.9 -- --

La 23.4 -- 15.4 22.8

Li 38 108 18.5 40.0

Ni 274 63.7 265.0 145.0

Pb 19.6 23.3 -- --

Rb 142.5 -- 17.0 27.0

Sc 20 11.9 -- --

Sr 104 731 227.0 213.0

Th 12.9 -- -- --

U 2.45 -- -- --

V 171 125 420.0 173.0

Y 226 37.9 -- --

Zr 106 213 163.0 141.0

Eu -- -- 1.07 1.7

Yb -- -- 1.90 3.4

Eu/Eu* -- -- 0.80 0.83

Table 2.1. Major and trace elemental analyses of Older Metamorphic Group pelitic schists,

ortho- and para-amphibolite rocks (after Saha et al., 1984; Saha et al., 1988). Note OMG pelites

are slightly richer in SiO2, K2O and poorer in TiO2, CaO and Al2O3 compared to the average

pelite of Shaw (1954) and richer in Cr, Ni, Cu and V and poorer in Sr, Y, Li and Zr. OMG ortho-

amphibolite analyses did not reflect any komatiitic affinity.

-- data not available


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The clustering around 3.55, 3.4 and 3.2Ga (207Pb/206Pb ages) for rounded detrital

zircon grains from OMG orthoquartzite suggests oldest limit of sedimentation age of

Singhbhum crustal province to be around 3.5Ga (Goswami et al.1995; Mishra et al. 1999).

Another U-Pb age data of 3.35 Ga OMG zircon is suggested as the first Pb-loss period

(Basu et al., 1996). Other ages (Ion microprobe 207Pb/206Pb) of the zircon from intrusive

OMTG cluster around 3.4 and 3.2 Ga (Mishra et al. 1999), 3448±19 Ma and 3527±17 Ma

(U–Pb zircon ages) (Acharyya et al. (2010a). Recently, Hoffman and Mazumder (2015)

based on new U-Pb zircon age data from OMG suggested that the deposition of the OMG

rocks would have taken place between 3.35 and 3.33 Ga (Hofmann and Mazumder, 2015).

Fig. 2.4. a) Plot of OMG ortho-amphibolite in CaO-MgO-Al2O3 diagram showing clustering in

Tholeiitic field without any Komatiitic trend. b) Chondrite-normalised REE pattern of the para-

and ortho-amphibolite of OMG. For comparing Archean tholiitic diabase of Newton Lake,

Minnesota was plotted. (Redrawn after Saha et al., 1984). Fig. 2.4. a) Plot of OMG ortho-amphibolite in CaO-MgO-Al2O3 diagram showing clustering

in Tholeiitic field without any Komatiitic trend. b) Chondrite-normalised REE pattern of the

para- and ortho-amphibolite of OMG. For comparing Archean tholiitic diabase of Newton Lake,

Minnesota was plotted. (Redrawn after Saha et al., 1984).

Fig. 2.5. a) Modal data of OMTG rocks plotted in Q-A-P-CI (Colour Index) diagram. Note that

the rocks are mainly tonalitic in composition with a few cluster in granodioritic to quartz-dioritic

to quartz monzo-dioritic fields. b) Chondrite-normalised REE pattern of the tonalite gneiss of

OMTG. Note the REE patterns of the SG (Phase I) also simulate the OMTG pattern with slightly

(20%) more total REE content for SG (Phase I) (compiled and redrawn after Saha et al., 1984).

Fig. 2.5. a) Modal data of OMTG rocks near Champua area plotted in Q-A-P-CI (Colour Index)

diagram. Note that the rocks are mainly tonalitic in composition with a few cluster in

granodioritic to quartz-dioritic to quartz monzo-dioritic fields. b) Chondrite-normalised REE

pattern of the tonalite gneiss of OMTG. Note the REE patterns of the SG (Phase I) also simulate


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2.3.2 Singhbhum Granite, Bonai Granite, Kaptipada Granite and Pal Lahara Gneiss

The OMTG is intruded by several granitic plutons forming a huge central composite

granitic batholith, namely Singhbhum Granite (SG), with three phases of emplacement age

between ~3.4 Ga and 3.1 Ga (Saha, 1994; Mukhopadhyay, 2001; Misra, 2006; Tait et al.,

2010). The SG occupies 8000 sq km area at the central part of the SC and emerges as the

most extensive unit of the craton. 12 different magmatic bodies identified in SG are grouped

into Phase I, II and III, based on the petrological and geochemical characteristics (Fig. 2.6).

The OMTG and the earliest phase of the SG (Phase I) are compositionally similar to the

Paleoarchean Tonalite-Trondhjemite (TTG) plutons from other continents (Saha, 1994;

Acharyya et al., 2010) (Table 2.2 and 2.3). REE distribution clearly classifies the SG into

1 2 3 4

Average OMTG,

Champua area

(Saha et al.,1984)

(n = 17)

Amitsoq Godthab, West

Greenland

(McGregor, 1979)

(n =25)

Nuk of Godthab, West

Greenland

(McGregor, 1979)

(n = 12)

Barberton, South

Africa (Condie and

Hunter, 1976)

(n = 7)

%

SiO2 67.57 66.70 65.7 71.0

TiO2 0.10 0.47 0.46 0.26

Al2O3 15.52 16.0 16.9 14.57

Fe2O3 1.38 -- -- 2.09

FeO 2.70 3.6 3.2 --

MnO 0.10 0.06 0.05 -- MgO 1.11 1.5 1.7 0.90

CaO 3.79 3.90 4.10 2.52

Na2O 5.20 4.6 5.0 5.95

K2O 1.55 1.5 1.6 1.67

P2O5 0.16 0.14 -- --

ppm

B 20 -- -- --

Ba 225 298 709 349

Be 5 -- -- --

Co 20 -- -- -- Cr 20 39 42 8

Cs 10 -- -- --

Cu 31 -- -- --

Ga 20 30 -- --

La 30 -- -- 31.7

Li 45 -- -- --

Ni 13.75 13 18 --

Pb 10 18 14 -- Rb 64 71 52 49

Sc 20 -- -- --

Sr 633 343 585 532

Th 6.95 -- -- --

U 2.55 -- -- --

V 37 -- -- --

Y 13 -- -- --

Zr 203 144 139 --

La 32 31.7

Ce 64 -- -- --

Nd 22 -- -- --

Sm 4.0 -- -- --

Eu 1.0 -- -- --

Tb 0.5 -- -- -- Yb 0.85 -- -- --

Lu 0.15 -- -- --

(Eu/Eu*)N 0.98 -- -- --

Table 2.2. Major, trace and REE data of Older Metamorphic Tonalitic Gneiss (OMTG)

of Champua area. Early Archean tonalite gneiss for comparison (Data Saha et al., 1984).

Table 2.2. Major, trace and REE data of Older Metamorphic Tonalitic Gneiss (OMTG)

of Champua area. Early Archean tonalite gneiss for comparison (Data Saha et al., 1984).



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two distinct categories, viz., SG Type-A and SG Type-B. Type-A incorporates the Phase I

and Phase II granites while Type-B granites exclusively belong to SG Phase III (Saha et

al., 1984). Type-A exhibits gently sloping REE pattern with slightly depleted HREE and

weakly negative to no Eu-anomaly (Table 2.4) (Fig. 2.7a). This pattern is similar to those

of OMTG with about 20% higher total REE abundance (Saha et al., 1884; Saha, 1994,

Mukhopadhyay, 2001). The SG (Phase I), the oldest fraction of SG, is almost similar in age

with OMTG, and the REE patterns of the two are also similar (Fig. 2.7a), though the

presence of xenoliths of OMTG within SG indicates an age difference (Saha et al., 1984).

This fact prompted workers to suggest that the protoliths of OMTG and SG might have

extracted from mantle at the same time but emplaced with a time interval of about 150 Ma

(Moorbath and Taylor, 1988).

(n = No. of sample)

Average

SG

Phase I (n =13)

Average

SG

Phase II (n =64)

Average

OMTG,

Champua area (n = 17)

Average Xenolithic

migmatite

of Bonai Granite (n=17)

SG Phase III

(n =21)

Average Porphyritic

component

of Bonai Granite

(n=37)

%

SiO2 70.96 72.04 67.57 67.32 72.54 73.45

TiO2 0.13 0.20 0.10 0.39 0.14 0.19

Al2O3 15.38 14.86 15.52 16.10 14.88 14.42

Fe2O3 1.13 0.85 1.38 3.03 0.95 1.47

FeO 1.72 1.27 2.70 1.07

MnO 0.03 0.04 0.10 0.05 0.03 0.02

MgO 0.91 0.68 1.11 1.18 0.48 0.43

CaO 2.89 2.20 3.79 2.53 2.00 1.13

Na2O 4.29 4.37 5.20 4.60 4.57 3.77

K2O 2.47 3.38 1.55 1.57 3.22 3.37

P2O5 0.09 0.11 0.16 0.12 0.12 0.06

ppm

B -- -- 20 -- -- --

Ba 212.0 371.0 225 -- 483.0 --

Be -- -- 5 -- -- --

Co 5.0 9.0 20 -- 6.0 --

Cr 8.0 11.0 20 -- 9.0 -- Cs -- -- 10 -- -- --

Cu 39.0 11.0 31 -- 10.0 --

Ga 14.0 17.0 20 -- 23.0 --

La 49.79 -- 30 -- 48.48 --

Li 18.0 24.0 45 -- 53.0 --

Ni 9.0 11.0 13.75 -- 9.0 --

Pb 10.0 18.0 10 -- 16.0 --

Rb 96.0 57.0 64 -- 117.0 -- Sc -- -- 20 -- -- --

Sr 436.0 329.0 633 -- 342.0 --

Th -- -- 6.95 -- -- --

U 4.8 6.2 2.55 -- 7.6 --

V 23.0 31.0 37 -- 21.0 --

Y 9.0 14.0 13 -- 19.0 --

Zr 113.0 155.0 203 -- 183.0 --

Table 2.3. Geochemical comparisons of Singhbhum Granite Phase I and II with OMTG and

Xenolithic component of Bonai Granite and Singhbhum Granite Phase III with porphyritic

component of Bonai Granite (Compiled from Saha et al., 1984; Sengupta et al., 1991). Table 2.3. Geochemical comparisons of Singhbhum Granite Phase I and II with OMTG and

Xenolithic component of Bonai Granite and Singhbhum Granite Phase III with porphyritic

component of Bonai Granite (Compiled from Saha et al., 1984; Sengupta et al., 1991).


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Singhbhum

Granite (Type-A)

OMTG

Tonalitic xenolith of

Bonai Granite

(n=3)

Singhbhum

Granite (Type-B)

Porphyritic calc-alkaline

granite

(n=3)

La 49.79 32 102 48.48 45.33

Ce 74.70 64 173 88.21 78.66

Nd 24.28 22 -- 30.36 --

Sm 4.10 4.0 9.35 4.91 5.98

Eu 0.93 1.0 1.54 0.73 2.16

Tb 0.36 0.5 0.23 0.45 0.76

Dy -- -- 4.00 -- --

Yb 0.87 0.85 0.63 1.72 3.19

Lu 0.12 0.15 -- 0.26 --

(Eu/Eu*)N 0.90 0.98 -- 0.56 --

(Ce/Yb)N -- -- 68.16 -- 6.60


Fig. 2.6. a) Q-Ab-Or ternary diagram showing fields of three phases of Singhbhum Granite

(phases I, II, III). The field of OMTG for comparison depicts almost complete overlap of SG

Phase I field. b) Na2O% vs. K2O binary plots of three phases of SG. Note the major overlapping

of fields of SG Phase I and II and partial overlap SC Phase III plots. c) Ga/Al vs. FeO (total)/

MgO plots show distinctly different fields for SG Phase III from SG Phase I and II. d) Ta vs.

Yb tectonic discrimination diagram plots show again SG Phase I and II are falling in the same

field which is distinct from the SG Phase III. Note majority of the plots show Volcanic Arc

setting (VAG: Volcanic Arc Granite; ORG: Orogenic Granite; WPG: Within Plate Granite; Syn-

COLG: Syn-collisional Granite) (redrawn after Saha, 1994).

Fig. 2.7. a) Q-Ab-Or ternary diagram showing fields of three phases of Singhbhum Granite

(phases I, II, III). The field of OMTG for comparison depicts almost complete overlap of SG

Phase I field. b) Na2O% vs. K2O binary plots of three phases of SG. Note the major overlapping

of fields of SG Phase I and II and partial overlap SC Phase III plots. c) Ga/Al vs. FeO (total)/

MgO plots show distinctly different fields for SG Phase III from SG Phase I andII. d) Ta vs. Yb


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Phase I Phase II Phase III

Composition Biotite granodiorite

to Trondhjemite

Biotite granodiorite Adamellite granite

Mean modal Plagioclase content 55.2% 49.2% 44.5%

Mean An-content of plagioclase 15.28 (An15-An25) 13.32(An15-An25) 8.22(An12-An17)

Mean modal K-feldspar 6.7 15.6 18.3

Mean modal biotite content 2.8 1.5 1.9

Mean modal muscovite content 0.1 0.15 0.70

Colour Index (C.I.) 8.0 6.9 6.6

Geochemical nomenclature K-poor granodiorite-

trondhjemite Granodiorite to adamellite granite

Trend with increasing D.I.

i) Ba and Ti show

decreasing trend

ii) Pb and Pb/K ratio increasing trend

iii)(Al3++Fe3+)/10*Ga

ratio decreases

i) Ba shows decreasing

trend

ii) (Al3++Fe3+) / 10*Ga ratio decreases;

iii) Zr and Pb/K increasing

i) Ba shows increasing

trend; ii)(Al3+ +

Fe3+)/10*Ga ratio decreases;

iii) Zr and Pb/K

decreasing

Cr/Ni ratio Higher Highest Lowest (Highest average

Ni)

Rb and Pb content Highest

FeOt/MgO Vs. (Ga/Al)*1000 diagram

Plots occupy the same field Plots occupy distinctly different field

REE pattern Gently sloping REE pattern with slightly depleted

HREE (La/Yb)N = 32.7

LREE enriched

fractionated pattern with

flat HREE (La/Yb)N = 21.5

(Eu/Eu*)N ratio Very weakly negative or no anomaly

[(Eu/Eu*)N = 0.90]

Moderate to strongly

negative anomaly [(Eu/Eu*)N = 0.56]

CaO and K2O/Na2O ratios CaO =3%

K2O/Na2O = 0.50

CaO =2.5%

K2O/Na2O = 0.70

Critical trace elemental ratios

K/Rb = 178.65 Rb/Sr = 0.22

Ba/Sr = 0.47

Sr = 370 ppm

K/Rb = 237.36 Rb/Sr = 0.43

Ba/Sr = 1.49

Sr = 342 ppm

Nomenclature based on REE and Trace elemental

characteristics

Singhbhum Granite

(Type-A)

Singhbhum Granite

(Type-B)

Table 2.4. Petrographic and geochemical characteristics of three phases of Singhbhum

Granite (Compiled from Saha et al., 1988, Saha, 1994).

Table 2.4. Petrographic and geochemical characteristics of three phases of Singhbhum

Granite (Compiled from Saha et al., 1988, Saha, 1994).

Fig. 2.7. a) Chondrite-normalised REE pattern of tonalite gneiss of OMTG. Note REE patterns

of SG (Phase I) simulate OMTG pattern with slightly (20%) more REE content for SG (Phase

I). SG Phase II also exhibit similar REE pattern with somewhat flat HREE patterns for a few

samples. REE pattern of xenolithic trondhjemite of Bonai Granite also simulates similar pattern

to OMTG and SG Type A (Phase I and II) with more fractionated overall REE pattern. b) REE

pattern of SG Type B (Phase III) show fractionated LREE, flat to moderately depleted HREE

and negative Eu-anomaly. Equigranular and porphyritic components of Bonai Granite also

simulates SG Type B. (compiled and redrawn after Saha et al., 1984; Sengupta et al., 1991).

Fig. 2.8. a) Chondrite-normalised REE pattern of the tonalite gneiss of OMTG. Note the REE

patterns of SG (Phase I) simulate the OMTG pattern with slightly (20%) more total REE content

for SG (Phase I). SG Phase II also exhibit similar REE pattern with a few samples showing


P a g e | 3 4

SG Type-B exhibits fractionated LREE enrichment pattern with flat HREE and is

characterized by moderate to strongly negative Eu-anomaly (Saha et al., 1984) (Fig. 2.7b).

Petrogenetic modeling suggested that (Saha, 1994) SG Type-A possibly have been

produced by 19% partial fusion of OMG ortho-amphibolite, while granodioritic melt of

SG-Type-B could be derived by partial fusion (30%) of a protolith of low potash andesitic

bulk chemistry. About 52% fractional crystallization is believed to have given rise to the

SG-Type-B (Saha, 1994).

The equivalent granite bodies of the SG are the Bonai Granite, Kaptipara Granite

(also known as Nilgiri Granite) and Chakradharpur Granite Gneiss, occurring at the

western, southeastern and northern margins of the SG batholiths respectively. The Bonai

Granite (Sengupta et al. 1991; Saha, 1994) has a triangular outline covering about 800 sq

km area and is separated from the main SG batholith by a IOG supracrustal belt of Jamda-

Koira horseshoe synclinorium (Fig. 2.3). It has 3 components: a) dominant unit of a

porphyritic granitoid of granite to granodioritic composition and rarely to tonalitic

composition (also known as ‘host granitoid’) and the associated b) less abundant

equigranular unit of two-mica trondhjemitic composition, and c) xenoliths of trondhjemite-

tonalite, banded migmatite, quartzite, BIF and mafic-ultramafic rocks within the above two

components. The field relationship of first two phases is not clear (Sengupta et al., 1991;

Mukhopadhyay, 2001; Misra, 2006) yet Saha (1994) inferred that the xenolithic migmatitic

components are older than the porphyritic components. Modal composition of the host

granitoid exhibits low Al2O3 (<15%) while the xenolithic granitoids, leucosomes in the

migmatites show higher Al2O3 (>15%). Modal (QAP diagram), normative (Q-Ab-Or

diagram) and the calc-alkaline trend of the three components of Bonai Granite suggest that

the prophyritic suite showed their clusters at the alkaline end of the calc-alkaline trend (Fig.

2.8). The trondhjemitic xenoliths have fractionated REE patterns with enriched LREE,

depleted HREE and insignificant Eu-anomaly and appear very similar to those of SG Type

A and OMTG with slightly more overall fractionation (Fig. 2.7a). While the host granitoids

(porphyritic component) and the equigranular trondhjemitic members show enriched

LREE, flat HREE with moderate (for equigranular trondhjemitic granite) to strong (for

porphyritic granites) negative Eu-anomaly (Sengupta et al., 1991) with the latter simulating

SG Type B (Fig. 2.7b). Resemblance of xenolithic migmatite of Bonai Granite with OMTG


P a g e | 3 5

and porphyritic component of Bonai Granite with SG Type B is corroborated by the

chemical data also (Table 2.3).

Kaptipada Granite (also called as Nilgiri Granite by Sarkar and Saha, 1977) exposed

at the southeastern part of the craton is surrounded by younger formations and is separated

from the main SG by a narrow strip of IOG phyllite and schistose epidiorite without any

direct observable contact between these two granite bodies. Kaptipada Granite is partly

migmatitic with xenoliths of amphibolites and talc schists and leucosomes of migmatitic

components are tonalitic in composition (Vohra et al., 1991). Like SG and Bonai Granite

amphibolite xenoliths and migmatite of Kaptipada Granite occur within the high Al2O3

tonalite-trondhjemite-granodiorite (TTG) bearing dominant component of the pluton.

Granite-granodiorite suite forms the youngest component (Saha, 1994; Vohra et al., 1991;

Dasgupta et al., 1992). The Al2O3–rich TTG component exhibits fractionated REE pattern

without Eu anomaly (Fig.2.9a) suggesting it as the partial melting product of an amphibolite

source with hornblende as a residual phase (Vohra et al.,1991). Geochemically, the TTG

components of Kaptipada and Poradiha have similar normative composition to SG Type

A (Fig.2.9b), while trace element and REE distributions differs slightly being more tonalitic

than SG Type B and contains less CaO, Sr and Zr and more K2O and SiO2 than OMTG

(Saha, 1994). Like SG, plots of Kaptipada Granite in bi-variate Y-Nb and (Y+Nb)-Rb

tectonic discrimination diagrams (after Pearce et al., 1984) cluster consistently in Volcanic

Arc Granite (VAG) field discussed in Saha, 1994 (Fig. 2.9c and d).

The first group of geochronological data on Kaptipada Granite was Rb-Sr whole-

rock dates of 3275±81 Ma (Vohra et al., 1991) and 2840±320 Ma with disturbed Rb-Sr

Fig. 2.8. a) Modal QAP diagram for all the three components of Bonai Granite. b) Normative

Ab-Or-An diagram. c) AFM diagram shows largely calc-alkaline trend of the Bonai Granite.

Note the porphyritic suite falls in alkaline end of the calc-alkaline trend. (redrawn after Sengupta

et al., 1991).CA : Calc-alkaline.

Fig. 2.9. a) Modal QAP diagram for all the three components of Bonai Granite. b) Normative

Ab-Or-An diagram. c) AFM diagram shows largely calc-alkaline trend of the Bonai Granite.

Note the porphyritic suite falls in alkaline end of the calc-alkaline trend. (redrawn after Sengupta

et al., 1991).


P a g e | 3 6

isotopic systematics (Saha, 1994). Later granitoid components of Kaptipara Granite (i.e.

Poradiha and Salchua tonalites, Kaptipada granodiorite-tonalite) yielded whole rock Pb-Pb

and Sm-Nd ages (3292+63/-66 Ma, 3225+102/-111 Ma, 3294±50 Ma, 3270±100 Ma,

3290±160 Ma) clustering at ~3.29 Ga which is equivalent to SG phase-II (Saha,1994;

Misra, 2006).

The large expanse of the southwestern part of the SC is occupied by

stratigraphically ill-defined unclassified gneiss which was later designated as Pal Lahara

Gneiss (PG) (Sarkar et al., 1990; Mazumder, 1996). PG is exposed over an area of 1200 sq

km, bordered by the Eastern Ghats Mobile Belt (EGMB) to the south, Mankarchua basin,

Fig. 2.9. a) REE pattern of Al2O3-rich TTG component of Kaptipada Granite exhibits a

fractionated REE pattern without Eu anomaly (Saha, 1994). b) Normative Q-Ab-Or diagram

showing plots and field of Kaptipada Granite. Note it largely overlaps that of SG Type A and is

distinctly different from that of OMTG. c) Y-Nb bivariate tectonic discrimination diagram

(after Pearce et al., 1984) showing plots of Kaptipada Granite falls in VAG (Volcanic Arc

Granite) and Syn-collisional granite (Syn-COLG) field. d) (Y+Nb) vs. Rb bivariate diagram

showing Kaptipada Granite falling in VAG field. The plots of SG also lie in the same fields as

those of Kaptipara Granite in c and d. (redrawn after Saha, 1994).

Fig. 2.10. a) REE pattern of Al2O3-rich TTG component of Kaptipada Granite exhibits a

fractionated REE pattern without Eu anomaly (Saha, 1994). b) Normative Q-Ab-Or diagram

showing plots and field of Kaptipada Granite. Note it largely overlaps that of SG Type A and is

distinctly different from that of OMTG. c) Y-Nb bivariate tectonic discrimination diagram

(after Pearce et al., 1984) showing plots of Kaptipada Granite falls in VAG (Volcanic Arc

Granite) and Syn-collisional granite (Syn-COLG) field. d) (Y+Nb) vs. Rb bivariate diagram

showing Kaptipada Granite falling in VAG field. The plots of SG also lie in the same fields as

those of Kaptipara Granite in c and d. (redrawn after Saha, 1994).


P a g e | 3 7

other volcanosedimentary basins and Malangtoli Lava in the north and the Malayagiri

greenstone belt and Deogarh supracrustal belt in the east and west, respectively. It is a

gneissic complex of lithoensemble of metasediments and granitoid rocks of different

components. The granite gneissic components are: 1) stromatic migmatite constituted by

the supracrustal rocks, 2) medium grained mesocratic, hornblende-magnetite bearing

granite, 3) banded, leucocratic, pink coloured granite gneiss, and 4) muscovite-

biotite±garnet bearing medium to coarse grained granitic gneiss. These granite gneisses

differ from all other granitoid bodies of the SC in terms of their composition

(syenomonzonitic affinity), presence of amphibole as major mafic mineral. They are also

typified by marginally negative Bouger anomaly in contrast to strong negative anomaly

expected over granites (Saha, 1994). This gneissic terrain also represents a zone of high

strain traversed by regional faults (Sarkar et al., 1990; Mahalik, 1994; Nash et al., 1996;

Crowe et al., 2001, 2003; Mohanty et al., 2008; Chetty, 2010).The terrain is bordered by

WNW-ESE trending Sukinda-Kerajung fault in the south, E-W trending Mankarchua-

Barkot fault in the north, NW-SE trending dextral Malayagiri shear zone in the east and

NW-SE trending sinistral Brahmani fault in the west (Mohanty et al., 2008) (Fig. 2.10).

Prasad Rao et al. (1964) delineated WNW-ESE trending Sukinda thrust which broadly

marks the boundary of SC and the EGMB.

The granite gneisses of Pal Lahara are syeno-monzonite (Saha, 1994) to Monzo-

granite to granitic in composition with metaluminous to peraluminous nature (Mohanty et

al., 2008)(Fig. 2.11a, b, c and d), which is in sharp contrast with all other silica rich tonalitic

to granodioritic Archean granites of SC and K-rich Proterozoic granitoids with higher

colour index (Saha, 1994). Geochemically, PG is similar to A-type granite with high

K2O/Na2O, Ba/Sr and low Cr and Ni content. This is in contrast with the S-type nature of

EGMB granites exposed to the south (Ramakrishnan et al., 1998) and calc-alkaline

trondhjemitic composition of Bonai Granite to the north (Sengupta et al, 1991). Plots in

AFM diagram suggested tholeiitic trend for PG except the leucogranite which showed calc-

alkaline trends (Saha, 1994) (Fig. 2.11e). Tectonic discrimination diagrams suggested

anorogenic nature of PG (Mohanty et al., 2008) (Fig. 2.11f and g). Mohanty et al., (2008)

reported a few REE studies showing strong LREE enrichment, flat HREE with

pronounced negative Eu-anomaly for hornblende-magnetite bearing grey granite fraction

while late alaskitic quartzo-feldspathic veins in grey granite show less enriched LREE, least

REE fractionation and pronounced positive Eu-anomaly. Positive Eu-anomaly is believed

to be due to plagioclase accumulation. Associated amphibolite xenoliths show lesser strong


P a g e | 3 8

REE fractionation, LREE enrichment and absence of Eu-anomaly (Fig. 2.11h).

Earlier workers correlated the unclassified gneiss of Pal Lahara area with Bonai

Granite in the north and the former as the basement to the supracrustal assemblages (Prasad

Rao et al., 1964). Sarkar et al. (1990) inferred that the T-shaped NNW and E-W trend of

Malayagiri basin is controlled by the basement configuration and grey and banded gneisses

of Pal Lahara Gneiss acted as the basement to the sedimentary assemblage. Mahalik (1994)

designated the granitic gneisses exposed between Pal Lahara and Kamakhyanagar as

‘Palkam gneiss’ and inferred that they act as basement to the metasedimentary succession

of low grade quartzite and schists exposed between Khamar and Pal Lahara town. Nash

(1996), based on Landsat imagery studies, delineated Rengali Domain which constitutes

the Pal Lahara Gneiss and associated supracrustals, delimited by Akul Fault zone in the

Fig. 2.10. Major litho-structural map of the southwestern margin of Singhbhum Craton and high

grade Eastern Ghat Mobile Belt (EGMB) with intervening high strain zone of Rengali Province

representing litho-ensemble of volcano-sedimentary succession of Malayagiri assemblage,

Deogarh supracrustals and high grade gneissic granitoids of Pal Lahara Gneiss. Note the network

of regional faults and shear zones affecting the rocks of Rengali Province with an overall WNW-

ESE trend abruptly different from NNE-SSW trending formations of EGMB. (Map compiled and

redrawn after Crowe et al., 2003, Nash et al., 1996; Chetty, 2010).

Fig. 2.11. Major litho-structural map of the southwestern margin of Singhbhum Craton and high

grade Eastern Ghat Mobile Belt (EGMB) with intervening high strain zone of Rengali Province

representing litho ensemble of volcano-sedimentary succession of Malayagiri assemblage,

Deogarh supracrustals and high grade gneissic granitoids of Pal Lahara Gneiss. Note the network

of regional faults and shear zones affecting the rocks of Rengali Province with an overall WNW-

ESE trend abruptly different from NNE-SSW trending formations of EGMB. (Map compiled and

redrawn after Crowe et al., 2003, Nash et al., 1996; Chetty, 2010).


P a g e | 3 9

north and the Kerajang fault to the south. Crowe et al. (2001, 2003) and Dobmeier and

Raith (2003) designated this belt as Rengali Province and suggested to represent a separate

crustal segment. Crowe et al. (2003) suggested that the Rengali Province constitutes a

Fig. 2.11. a) Composition of Pal Lahara Gneiss in normative QAP diagram (after Le Maitre,

1989) showing monzo-granitic composition ; b) Alkali-Silica diagram ( Middlemost, 1985)

showing granitic composition; c) Ab-An-Or diagram exhibits cluster of PG in granite field; d)

A/CNK vs.A/NK diagram (after Maniar and Piccoli, 1989) exhibits metaluminous to

peraluminous nature of PG; e) AFM diagram shows plots of PG in tholeiitic field, while the

pink coloured leucogranite pink grey gneiss fall in calc-alkaline field; f) FeO/(FeO+MgO) vs.

SiO2 tectonic discrimination diagram (after Maniar and Piccoli, 1989) show anorogenic nature

of PG; g) Al2O3 vs. SiO2 discrimination diagram also exhibit anorogenic nature of PG [RRG-

Rift-related granitoid, CEUG-Continental epiorogenic uplift granitoid, POG-Post-orogenic

granitoid, IAG-Island arc Granitoid, CAG-Continental arc granitoid, CCG- Continental

collision granitoid]; h) REE patterns showing strong LREE enrichment, flat HREE with

pronounced negative Eu-anomaly for hornblende-magnetite grey granite while late alaskitic

quartzo-feldspathic veins in the former show less enriched LREE, least REE fractionation and

pronounced positive Eu-anomaly suggestive of plagioclase accumulation. Associated

amphibolite enclaves show least REE fractionation, LREE enrichment and absence of Eu-

anomaly (all plots are redrawn after Mohanty et al., 2008). Fig. 2.12. a) Composition of Pal Lahara Gneiss in normative QAP diagram (after Le Maitre,

1989) showing monzo-granitic composition ; b) Alkali-Silica diagram ( Middlemost, 1985)

showing granitic composition; c) Ab-An-Or diagram exhibits cluster of PG in granite field; d)

A/CNK vs.A/NK diagram (after Maniar and Piccoli, 1989) exhibits metaluminous to


P a g e | 4 0

part of Bundelkhand craton and was juxtaposed with the EGMB by dextral transport along

a transcurrent shear possibly in late Mesoproterozoic time. Chetty (2010), however,

concluded that the granulite facies rocks of Rengali Domain represent a part of the EGMB

transported onto the SC through high angle thrusting. In support of this conclusion he put

forward evidences, like common cooling history of Rengali Province and EGMB as

inferred from 40Ar/39Ar data (Crowe, 2001), similarities in age data of Rengali Province

(Older Hornblende age of 699 Ma) and EGMB rocks (650 Ma) (Mezger and Cosca, 1999)

and field evidences like similar disposition of granulite facies rocks in association with the

2.8Ga gneissic fabrics.

2.3.3 Iron Ore Group Supracrustal rocks

The extensive SG batholith encloses synformal keels of banded iron formation (BIF)-

bearing mafic volcanics-dominated greenstone belts widely known as Iron Ore Group

(IOG). These belts are occurring as linear belts around the Singhbhum batholiths in its

eastern, western and southern margins and are known as Eastern IOG (Gorumahisani–

Badampahar), Western IOG (Noamundi–Jamda–Koira) and Southern IOG (Tomka–

Daitari) belts, respectively (Fig.2.3). In these IOG belts, the BIFs are intimately associated

with volcanic and volcaniclastic deposits with ferruginous and manganiferous shales, tuffs,

ultramafic–mafic lavas (locally felsic), BIFs, cherts and minor carbonates at the top (Dunn

and Dey 1942; Murthy and Acharya, 1975; Chakraborty and Majumder 1986;

Acharyya,1993; Saha 1994; Mukhopadhyay 2001; Bhattacharya et al., 2007; Ghosh and

Mukhopadhyay 2007; Mukhopadhyay et al., 2008; Beukes et al., 2008; Bose 2009; Ghosh

et al., 2010).Younger Neoarchean to Mesoproterozoic volcano-sedimentary successions

unconformably overlie the granite–greenstone (IOG) successions (vide reviews in Dunn,

1940; Acharyya, 1993;Saha, 1994; Mazumder, 1996; Sengupta et al., 1997;

Mukhopadhyay, 2001; Misra, 2006; Mukhopadhyay et al., 2006, 2008). The IOG belts are

the important repository of BIF-hosted, high-grade hematitic iron ore deposits of India. In

southern IOG belt a podiform chromiferous ultramafic body overlies the BIF (Auge´et al.

2003; Mondal et al., 2007) with a thrusted contact (Mukhopadhyay et al., 2008). In western

IOG belt carbonates are associated with IOG succession in the form of siliceous

stromatolitic dolomites (Sarkar, 1989). Preliminary studies suggested intertidal to subtidal

depositional setting for BIF of western IOG belt on the basis of columnar stromatolite

association (Sarkar, 1989).


P a g e | 4 1

A major controversy exists regarding the relative ages of the BIFs of eastern,

western and southern IOG belts as well as their stratigraphic position with respect to the

SG. One group of workers considered that the SG as the basement to the IOG succession

(Mukhopadhyay, 1976; Banerji, 1977; Banerjee, 1982; Iyenger and Murthy, 1982), while

others suggested that they are older to SG (Dunn and Dey 1942; Sarkar and Saha, 1977,

1983). Subsequently, Saha et al. (1988) and Saha (1994), based on field observations

suggested that phase III of the SG is intrusive into the IOG rocks, while SG phases I and II

are older than it.

Another unresolved issue is whether the BIFs of the eastern, western and southern

IOG belts belong to the same age (Dunn 1940; Dunn and Dey 1942; Sarkar and Saha, 1977,

1983; Basu et al. 2008) or to different ages (Banerji, 1977; Iyenger and Murthy, 1982,

Acharya, 1984; Saha, 1994; Mukhopadhyay, 2001; Bose, 2009). Acharya (1984) proposed

that the BIF of eastern IOG belt is the oldest and is unconformably overlain by southern

BIFs of Malayagiri Hill area, which in turn, is unconformably overlain by the BIF of the

western belt. Structural analyses and other field studies, however, nullified presence of

angular unconformities as suggested by Acharya (vide Mukhopadhyay, 2001).

Lithological, mineralogical and geochemical characterizations of the BIFs of these three

belts were attempted to resolve this stratigraphic issue (Acharya 1984; Chakraborty and

Majumder, 1986; Saha 1994; Mukhopadhyay 2001; Bose, 2009).The lithological

association as well as their low grade greenschist facies metamorphism in all the IOG belts

remains largely similar while they differ characteristically in finer lithological and

geochemical aspects. Eastern IOG belt consists of phyllites, quartzites (BHJ, BHQ and

BMQ), mica schists, mafic lavas, tuff and sill-like epidiorite (Saha, 1994), while the

western IOG belt comprises of pellitic and psammitic detrital sediments, chemogenic

ferruginous sediments and cherts (including BHJ, BMJ, BHQ and banded grunerite

quartzite), mafic lavas, acid-intermediate tuffs, tuffeceous phyllites and characteristically

dolomite at the top. Southern IOG belt consists of bimodal volcanic-BIF and chromite-

bearing ultramafic rocks in Daitari-Tomka hill of Odisha (Prasad Rao et al., 1964;

Chakraborty et al., 1980; Acharyya, 1993; Banerjee, 1997; Acharya, 2002), which can be

classified into four lithostratigraphic units, viz., basalt, dacitic volcanic rocks, BIF, and

chromite-bearing ultramafics (Mukhopadhyay et al., 2008).

Metabasalts of western IOG belt exhibit calc-alkaline trend, whereas the eastern

IOG metavolcanic rocks show a tholeiitic trend (Sengupta et al., 1997). Unlike other

platformal greenstone belts the western IOG succession does not contain komatiites (Bose


P a g e | 4 2

2009, p. 15), while they are reported from the eastern IOG belt (Sahu and Mukherjee, 2001).

However, Bose (2009) disagreed their komatiitic nature on the basis of lack of diagnostic

trace elemental data. Acharyya (1993) considered volcanics-BIF association of IOG to be

analogous of Phanerozoic ophiolites and suggested that the eastern belt represents a

segment of the Archaean oceanic crust, while the western belt was floored by continental

crust which however, is argued against as Badampahar-Gorumahisani (eastern) belt

contains basal siliciclastic rocks not an oceanic crust (Chakraborty and Majumder, 1986).

Saha (1994), classified metalavas of southern IOG belt into low-magnesia (0.88-2.33%),

moderate-magnesia (4.51-11.48%) and high-magnesia (15.93-26.65%) lavas and

concluded that the high-magnesia lavas are not komatiitic in nature, do not exhibit spinifex

texture and are very low in CaO content compared to typical komatiite (Table 2.5) (Fig.

2.12d).Such variation in lavas suggested distinctive Fe-enrichment trend (Bose, 2009) (Fig.

2.17b). Plots of metalavas of southern IOG belt in MgO-FeO-Al2O3 diagram suggested that

high-Mg lavas represent ocean - floor basalt, moderate - Mg lavas belong to tholeiitic basalt

evolved from spreading centres and the low-Mg acid-intermediate flows are derived from

partial melting of mafic lower crust (Saha, 1994) (Fig. 2.12d). Sengupta et al. (1997)

utilized Cr, together with other immobile elements, Zr, Y and Ti, to recognize magma

trends of IOG volcanics by plotting them in a (Zr + Y)-(TiO2*100)-Cr triangular diagram

(after Davies et al., 1979).The plots suggest that the western IOG belt belongs to Archean

calc-alkaline trend while most of the samples from the eastern belt and a few from western

belt belong to Archaean tholeiitic-magnesian trend. The rest of the samples plot between

these two trends (Fig. 2.12e).This fact and the REE pattern studies (Fig.2.12f, g and h)

suggest three broad groups of basic volcanic rocks from the IOG belts of SC (Sengupta et

al., 1997). Detail geochemical evaluation of the dacitic, mafic and ultramafic volcanics of

the southern IOG belts based on relative abundances of LILE and HFSE and chondrite- and

MORB-normalised REE and tectonic discrimination diagrams using trace elements like Ta,

Nb, Yb, Th, Ti and Zr (after Pearce et al., 1984; Pearce and Peate, 1995; Knittel and Oles,

1995), Mukhopadhyay et al. (2012) demonstrated that the basic volcanics of SIOG belt

show characteristics of subduction zone volcanic rocks and picritic to boninitic mafic rocks

of oceanic arc setting without continental crustal overprints similar to Eoarchean Isua

Greenstone Belt (cf. Polat et al., 2008) (Fig. 2.13), while, the dacitic lavas exhibit the non-

plume source volcanic arc setting (Mukhopadhyay et al., 2008) (Fig. 2.14a, b and c).


P a g e | 4 3

Low-Magnesia

(n=7)

Moderate-

magnesia

(n=7)

High-

magnesia

(n=7)

Basic lavas

(data after Mukhopadhyay et al., 2012)

(data after Saha, 1994)

%

SiO2 68.96 53.96 50.47 47.50 49.82 50.41 50.45 49.56 48.82 50.58 50.05

TiO2 0.31 0.52 0.87 0.82 0.87 0.84 0.87 0.89 0.49 0.44 0.47

Al2O3 16.60 13.60 11.88 7.09 10.27 9.99 10.25 10.51 10.28 9.15 9.19

Fe2O3 2.14 4.40 2.95 16.38 17.00 16.92 16.75 17.44 11.46 12.38 11.27

FeO 2.09 7.91 4.99

MnO 0.06 0.17 0.09 0.23 0.20 0.20 0.20 0.21 0.15 0.18 0.21

MgO 1.58 7.28 21.83 20.64 8.85 8.59 8.63 8.97 12.95 17.10 16.64

CaO 2.63 7.61 2.99 6.23 7.87 7.77 7.61 6.91 8.63 6.36 5.56

Na2O 2.90 2.45 0.55 0.21 1.97 1.88 1.89 2.02 1.87 1.65 1.19

K2O 1.65 0.53 0.31 0.02 0.12 0.16 0.14 0.09 0.16 0.41 0.57

P2O5 -- -- -- 0.08 0.08 0.08 0.08 0.08 0.67 0.06 0.05

LOI -- -- -- 2.20 3.00 3.20 3.20 3.40 5.30 2.10 4.90

ppm

Ba -- -- -- 10.9 18.2 27.2 25.0 17.3 79.6 160.5 231.4

Rb -- -- -- 0.9 3.0 5.3 4.0 2.2 3.5 11.8 15.0

Sr -- -- -- 11.8 171.9 181.4 175.6 174.9 315.7 106.8 41.9

Cs -- -- -- 0.1 0.1 0.1 0.1 0.1 0.1 0.2 0.1

Ga -- -- -- 7.0 11.4 11.9 11.9 12.3 10.3 11.1 13.5

Ta -- -- -- 0.3 0.4 0.4 0.6 0.3 0.7 0.3 0.5

Nb -- -- -- 3.0 3.6 3.5 3.9 3.3 3.3 2.7 3.4

Hf -- -- -- 0.9 0.7 0.7 0.7 0.8 0.7 0.7 1.0

Zr -- -- -- 36.2 23.7 26.1 25.3 26.1 28.6 31.0 38.7

Y -- -- -- 13.5 22.0 23.1 22.7 24.5 13.4 12.7 12.9

Th -- -- -- 0.5 0.3 0.3 0.3 0.4 0.9 0.9 1.0

U -- -- -- 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01

Cr -- -- -- 1185.1 129.7 131.2 142.0 170.4 417.5 721.4 886.5

Ni -- -- -- 319.8 50.3 48.9 47.3 46.4 91.7 155.5 158.6

Co -- -- -- 65.1 53.7 53.8 48.5 49.3 48.4 60.5 56.8

Sc -- -- -- 24.5 34.1 35.3 34.3 37.4 28.1 27.7 27.2

V -- -- -- 180.1 281.6 293.4 297.3 311.5 177.3 173.6 167.2

Cu -- -- -- 62.3 242.9 183.4 120.5 94.8 179.6 61.7 22.3

Pb -- -- -- 4.5 14.3 127.7 7.5 124.8 3.3 2.6 3.5

Zn -- -- -- 78.9 72.4 73.3 69.0 82.6 39.5 41.5 49.8

-- -- --

La -- -- -- 3.65 3.34 3.49 3.44 3.65 6.98 6.70 6.55

Ce -- -- -- 9.53 8.87 9.48 9.04 9.91 14.97 14.80 13.80

Pr -- -- -- 1.20 1.10 1.19 1.14 1.21 1.55 1.52 1.46

Nd -- -- -- 7.37 7.02 7.20 7.12 7.45 8.38 8.11 7.92

Sm -- -- -- 1.93 1.93 2.08 1.96 2.16 1.78 1.76 1.82

Eu -- -- -- 0.58 0.72 0.71 0.71 0.77 0.64 0.59 0.50

Gd -- -- -- 2.67 2.98 3.07 2.98 3.29 2.35 2.31 2.27

Tb -- -- -- 0.46 0.56 0.59 0.56 0.62 0.40 0.38 0.37

Dy -- -- -- 2.29 3.28 3.39 3.19 3.53 2.00 1.85 1.92

Ho -- -- -- 0.46 0.70 0.75 0.73 0.78 0.42 0.41 0.42

Er -- -- -- 1.35 2.32 2.39 2.30 2.45 1.43 1.36 1.31

Tm -- -- -- 0.20 0.38 0.38 0.39 0.41 0.22 0.23 0.22

Yb -- -- -- 1.07 2.15 2.18 2.17 2.39 1.32 1.21 1.24

Lu -- -- -- 0.14 0.31 0.31 0.33 0.34 0.19 0.18 0.19

∑REE -- -- -- 32.90 35.67 37.20 36.04 38.97 42.63 41.40 39.98

Eu/Eu* -- -- -- 0.78 0.86 0.86 0.88 0.95 0.95 0.90 0.75

(La/Yb)N -- -- -- 2.44 1.15 1.15 1.09 3.80 3.80 3.98 3.78

(Ce/Yb)N -- -- -- 2.47 1.21 1.21 1.15 3.15 3.15 3.40 3.09

(La/Sm)N -- -- -- 1.22 1.08 1.08 1.09 2.53 2.53 2.45 2.32

(Gd/Yb)N -- -- -- 2.06 1.17 1.17 1.14 1.48 1.48 1.58 1.51

La/Nb -- -- -- 1.22 0.92 1.01 0.89 1.10 2.13 2.48 1.92

Th/Nb -- -- -- 0.17 0.09 0.10 0.08 0.11 0.28 0.33 0.28

Th/La -- -- -- 0.14 0.10 0.10 0.09 0.10 0.13 0.13 0.15

Ba/La -- -- -- 3.00 5.44 7.80 7.27 4.75 11.41 23.95 35.33

Pb/Ce -- -- -- 0.47 1.61 13.47 0.83 12.60 0.22 0.18 0.25

Table 2.5. Chemical composition of mafic lavas of southern IOG belt (data after Saha,

1994; Mukhopadhyay et al., 2012)

Table 2.5. Chemical composition of mafic lavas of southern IOG belt (data after Saha,

1994; Mukhopadhyay et al., 2012)


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Fig. 2.12. Geochemical proxies of IOG basic volcanic rocks. a) Mg-A-(Fet+Ti) cation plot

diagram (after Jensen , 1976) showing two clusters for composition of EIOG and SIOG lavas,

viz., (High Mg- and high Fe-) tholeiitic basalt and Mg-rich basaltic komatiite, while WIOG

basic lavas showed basaltic to high-Mg tholeiitic basaltic composition. b) CaO-MgO-Al2O3

plots of SIOG metabasic lavas (after Saha, 1994). c) AFM diagram showing higher Al2O3

content for SIOG and WIOG basic volcanics (data Sengupta et al., 1997). d) MgO-FeO-Al2O3

diagram of SIOG metalavas showing high Mg lavas represent ocean-floor basalts, moderate-

Mg type represent spreading axis basalt and low-Mg type is of orogenic nature (after Saha,

1994). e) T-Y-C (TiO2 x 100, Y+Zr, Cr) plot for basic volcanic rocks of IOG belts (after Davies

et al.,1979) suggesting that the western belt plots belong to Archaean calc-alkaline trend while

most of the eastern belt and a few western belt samples show Archaean tholeiitic-magnesian

trend. The other samples plot between these two trends (data Sengupta et al., 1997). f) Flat

chondrite-normalized REE patterns of IOG basic volcanic samples of one group showing lowest

total REE abundance with [Ce/Yb]N and [La/Sm]N ratios around one (broadly unfractionated)

and positive Eu-anomaly. g) Differentiated REE pattern [significantly higher (Ce/Yb)N ratios]

with higher total REE abundance compared to group shown in f , higher (La/Sm)N ratio

indicating fractionated LREE with flat HREE patterns and strong negative Eu-anomaly for

another group of basic volcanics. h) the third group of basic volcanics of IOG showing REE

patterns intermediate between the two groups shown in fig. f and g (fig. e, f and g are redrawn

from Sengupta et al.,1997) .

Fig. 2.13. Geochemical proxies of IOG basic volcanic rocks. a) Mg-A-(Fet+Ti) cation plot

diagram (after Jensen , 1976) showing two clusters for composition of EIOG and SIOG lavas,

viz., (High Mg- and high Fe-) tholeiitic basalt and Mg-rich basaltic komatiite, while WIOG

basic lavas showed basaltic to high-Mg tholeiitic basaltic composition. b) CaO-MgO-Al2O3

plots of SIOG metabasic lavas (after Saha, 1994). c) AFM diagram showing higher Al2O3

content for SIOG and WIOG basic volcanics (data Sengupta et al., 1997). d) MgO-FeO-Al2O3


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Chondrite- and MORB-normalized trace element patterns and REE-patterns of

dacitic and basic volcanic rocks of SIOG belt show similar oceanic arc volcanic signatures

(enrichment of LILE like Th, Ba, U over HFSE like Nb and Ta; strong enrichment of LREE

and HREE depletion with very low Eu/Eu*cn anomaly depicting limited plagioclase

fractionation in the melt) (Mukhopadhyay et al., 2012) (Fig. 2.14d, e, f, g and 2.15d, e, f

and g).

Mukhopadhyay et al. (2012) also suggested that chromiferous ultramafic rocks of

SIOG belt show ophiolitic affinity reflected by: 1) more enrichment of LILE over N-MORB

compared to the basic and dacitic lavas, b) flat LILE and HFSE Primitive Mantle- and

MORB-normalised patterns with negative Nb-anomaly, slight positive Ti-anomaly, and c)

enrichment of Th over La (Fig. 2.15a and b). U-shaped chondrite- and N-MORB-

normalized REE pattern of ultramafic rocks reflects enrichment of LREE and HREE with

respect to the MREE, characteristic to many Phanerozoic ophiolitic peridotites (Bodinier

and Godard, 2003 in Mukhopadhyay, 2012) (Fig. 2.15c and d). Nb and Ta retention in

residual rutile phase during partial melting of the subducting oceanic crust was indicated

Fig. 2.13. Geochemical behaviour of southern IOG basalts. a) Nb/Y vs. Zr/Ti diagram (after Pearce,

1996) shows plots of metabasic volcanics in basalt field. b) Nb/Yb vs. Th/Yb tectonic

discrimination diagram (Pearce and Peate, 1995) and c) Ti/Zr vs Zr plots (Knittel and Oles, 1995)

exhibit field of modern subduction zone for SIOG volcanics. Note similarity in composition with

basic volcanics of Isua Greenstone Belt (compositional fields for the Isua Greenstone Belt after

Polat et al., 2008). d) Chondrite-normalized (Sun and McDonough, 1989) and e) Normal-MORB

normalized trace element spider diagram of basalt showing Nb, Zr and Ti-troughs, sub-chondritic

Nb/Ta and Zr/Nb values suggestive of oceanic arc setting without continental crustal overprints. f)

Chondrite-normalized (Sun and McDonough, 1989) and, g) N-MORB normalized REE pattern of

basic volcanics show LREE enrichment and HREE depletion with very low Eu/Eu*anomaly (data

after Mukhopadhyay et al., 2012) Fig. 2.14. Geochemical behaviour of southern IOG basalts. a) Nb/Y vs. Zr/Ti diagram (after Pearce,

1996) shows plots of metabasic volcanics in basalt field. b) Nb/Yb vs. Th/Yb tectonic

discrimination diagram (Pearce and Peate, 1995) and c) Ti/Zr vs Zr plots (Knittel and Oles, 1995)

exhibit field of modern subduction zone for SIOG volcanics. Note similarity in composition with

basic volcanics of Isua Greenstone Belt (compositional fields for the Isua Greenstone Belt after

Polat et al., 2008). d) Chondrite-normalized (Sun and McDonough, 1989) and e) Normal-MORB

normalized trace element spider diagram of basalt showing Nb, Zr and Ti-troughs, sub-chondritic

Nb/Ta and Zr/Nb values suggestive of oceanic arc setting without continental crustal overprints. f)

Chondrite-normalized (Sun and McDonough, 1989) and, g) N-MORB normalized REE pattern of

basic volcanics show LREE enrichment and HREE depletion with very low Eu/Eu*anomaly (data

after Mukhopadhyay et al., 2012)


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by low (subchondritic) Nb/Ta ratio and negative Nb-anomaly in ultramafics of southern

IOG belt.

Fig. 2.14. Geochemical behaviour of the southern IOG dacitic rocks. a) Nb/Y vs. Zr/TiO2

diagram (after Pearce, 1996) showing cluster of plots of southern IOG dacite. b) Nb, Y, Ta,

Rb and Yb tectonic discriminant diagrams (after Pearce et al., 1984) suggests volcanic arc

setting for the southern IOG dacite. c) Nb/Y vs Zr/Y diagram (fields after Condie, 2005) for

the dacitic volcanics showing plots lying in the non-plume source arc field. d) Chondrite-

normalized (Sun and McDonough, 1989) and e) MORB-normalized (Pearce, 1983) trace

element spider diagram, suggesting enrichment of LILE (e.g. Th, Ba, U) over HSFE (e.g. Nb

and Ta). f) Chondrite normalized and g) N-MORB normalized REE patterns show strong

enrichment of LREE and HREE depletion with low Eu/Eu* anomaly depicting limited

plagioclase fractionation in the melt (redrawn after Mukhopadhyay et al., 2012).

Fig. 2.15. Geochemical behaviour of the southern IOG dacitic rocks. a) Nb/Y vs. Zr/TiO2

diagram (after Pearce, 1996) showing cluster of plots of southern IOG dacite. b) Nb, Y, Ta,

Rb and Yb tectonic discriminant diagrams (after Pearce et al., 1984) suggests volcanic arc

setting for the southern IOG dacite. c) Nb/Y vs Zr/Y diagram (fields after Condie, 2005) for

the dacitic volcanics showing plots lying in the non-plume source arc field. d) Chondrite-

normalized (Sun and McDonough, 1989) and e) MORB-normalized (Pearce, 1983) trace

element spider diagram, suggesting enrichment of LILE (e.g. Th, Ba, U) over HSFE (e.g. Nb

and Ta). f) Chondrite normalized and g) N-MORB normalized REE patterns show strong

enrichment of LREE and HREE depletion with low Eu/Eu* anomaly depicting limited

plagioclase fractionation in the melt (redrawn after Mukhopadhyay et al., 2012).

Fig. 2.15. Geochemical

characteristics of

chromiferous ultramafic

rocks of southern IOG

belt. a) Primitive mantle

normalized (Sun and

McDonough, 1989) and

b) MORB-normalized

(Pearce, 1983) trace

element spider diagram

shows flat LILE, HFSE

with pronounced negative

Nb-anomaly, positive Ti-

anomaly and a slight

enrichment of Th relative

to La akin to the patterns

of Phanerozoic ophiolitic

peridotites and supra-subduction zone fore arcs. c) Chondrite normalized and d) N-MORB

normalized REE patterns shows a shallow ‘U’-shaped pattern with subtle enrichments for

LREE and HREE with respect to MREE. Such U-shaped patterns are characteristically

reported from many Phanerozoic ophiolitic peridotites (data Mukhopadhyay et al., 2012).


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Pelitic members of the western IOG belt were classified into lower shale formation

(LSF), shale interbedded within BIF (MSF) and upper shale formation (USF). LSF contains

more SiO2, while MSF is enriched in Fe2O3 and the USF contains comparable Al2O3 and

lower SiO2 and Fe2O3 than the MSF. Associated volcanic tuffs show chemistry similar to

LSF attributing volcanic origin to the latter, while enrichment in Al2O3, TiO2, Ni and Co in

USF suggests their lateritisation in the continental source area (Fig. 2.16a). Major and trace

elemental studies on BIFs of eastern and southern IOG belts revealed broad similarity with

the Lake Superior oxide facies BIF but differ in lower trace element content in BIFs of IOG

succession (Table 2.6) (Majumder et al., 1982) and lends support to the primary

sedimentary origin of magnetite in eastern and southern BIFs. Preliminary REE studies

suggested similar REE patterns as those of BIFs of other parts of the world and their low

total REE content indicated negligible contribution of clastic components (Majumder et al.,

1982). High Eu/Sm ratios of BMQ and BMJ of the IOG belts are (0.64 and 0.53

respectively) comparable to the range of pre-2.5Ga BIF (0.40-1.22) (Fryer, 1977) and again

1 2 3 4 5 6

(data after Majumder et al., 1982) (data after Mukhopadhyay et al., 2012)

SiO2 47.02 47.20 50.50 36.67 41.11 35.66

TiO2 -- -- -- 0.02 0.01 0.02

Al2O3 0.70 1.39 3.00 0.25 0.03 0.24

Fe2O3 44.16 35.40 26.90 61.38 56.67 62.22

FeO 8.28 8.20 13.00 -- -- --

MnO 0.06 0.73 0.22 0.01 0.01 0.02

MgO 0.13 1.24 1.53 0.03 0.05 0.01

CaO 0.17 1.58 1.51 0.20 0.17 0.21

Na2O 0.10 0.00 0.31 0.02 0.00 0.03

K2O 0.13 0.14 0.58 0.02 0.01 0.03

P2O5 0.07 0.06 0.21 0.01 0.01 0.01

LOI -- -- -- 0.98 0.56 1.20

Total 99.59 98.63 99.65

Ba -- 180 170 19.10 18.8 27.2

Rb -- -- -- 0.4 0.2 0.3

Sr -- 42 98 6.8 7.3 10.2

Cs -- -- -- 0.2 0.1 0.2

Ga -- -- -- 0.8 0.6 0.9

Ta -- -- -- 5.3 1.8 8.6

Nb -- -- -- 0.9 0.9 1.2

Hf -- -- -- 0.1 0.0 0.1

Zr -- 56 84 1.1 0.4 1.4

Y -- -- -- 2.8 1.4 5.0

Th -- -- -- 0.1 0.1 0.2

U -- -- -- 0.12 0.08 0.16

Cr -- 122 78 1.4 2.4 2.0

Ni -- 92 83 3.4 2.5 4.4

Co -- 27 38 99.5 134.2 163.0

Table 2.6. Chemical composition of BIF of IOG belts of Singhbhum craton (data after

Majumder et al., 1982; Mukhopadhyay et al., 2012).1 – av. of Odisha BIF, 2 – Lake Superior

oxide facies BIF, 3- Algoma oxide facies BIF. 4, 5 and 6 – representative analyses of southern

BIF. Table 2.6. Chemical composition of BIF of IOG belts of Singhbhum craton (data after

Majumder et al., 1982; Mukhopadhyay et al., 2012).1 – av. of Odisha BIF, 2 – Lake Superior

oxide facies BIF, 3- Algoma oxide facies BIF. 4, 5 and 6 – representative analyses of southern

BIF.


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Sc -- -- -- 0.7 0.6 0.7

V -- 30 97 10.3 8.2 7.3

Cu -- 10 96 11.7 11.0 20.6

Pb -- -- -- Bdl Bdl Bdl

Zn -- -- -- 245.2 16.5 235.6

La -- -- -- 4.52 2.31 5.58

Ce -- -- -- 5.26 2.56 7.02

Pr -- -- -- 0.50 0.25 0.69

Nd -- -- -- 2.77 1.36 3.78

Sm -- -- -- 0.48 0.27 0.75

Eu -- -- -- 0.22 0.13 0.33

Gd -- -- -- 0.40 0.17 0.66

Tb -- -- -- 0.04 0.02 0.07

Dy -- -- -- 0.32 0.14 0.63

Ho -- -- -- 0.07 0.03 0.14

Er -- -- -- 0.20 0.08 0.36

Tm -- -- -- 0.04 0.02 0.07

Yb -- -- -- 0.26 0.08 0.46

Lu -- -- -- 0.05 0.02 0.09

∑REE -- -- -- 15.15 7.42 20.61

Ce/Ce* -- -- -- 0.59 0.55 0.61

Eu/Eu* -- -- -- 2.33 2.74 2.21

Y/Ho -- -- -- 38.25 40.12 36.27

supported absence of detrital/extrabasinal contribution to the BIFs (Saha, 1994) (Fig.

2.16b). Mukhopadhyay et al. (2012) demonstrated that PAAS-normalised REE patterns

(Fig. 2.16c) of the southern BIFs resemble typical Archean and Paleoproterozoic BIFs of

the world and simulates the oldest BIFs from Isua Greenstone belt (Bolhar et al., 2004; Frei

and Polat, 2007).

A minimum age of ~3.1 Ga was postulated for the IOG from granitoids (SG Phase

III ) intrusive into the three IOG belts ( cf. Paul et al., 1991 ; Misra et al., 1999 ). Recent

Fig. 2.16. a) Al2O3-SiO2-Fe2O3 diagram showing distinct clusters for different pelitic

formations of the western IOG belt (After Saha, 1994). b) REE patterns of banded iron

formation (BIF) and associated rocks of Western IOG belt (after Majumder et al., 1982). Note

the positive Eu-anomaly of Fe-ore, BMQ and BMJ samples while the quartzites show negative

Eu-anomaly. High Eu/Sm ratios of BMQ and BMJ is comparable with Precambrian BIF older

than 2.5Ga (cf. Fryer, 1977) and low Eu/Sm ratio of quartzite suggests its derivation from

clastic sedimentation. c) REE composition pattern of the BIF (normalization values of PAAS

after McLennan, 1989) from southern IOG belt (data after Mukhopadhyay et al., 2012) showing

prominent positive Eu-anomaly, suprachondritic Y/Ho ratios nearer to the seawater value (~

44) exhibited oxygen-deficient marine signature of bottom water where reduction of Eu3+ to

Eu2+ takes place due to hydrothermal activity of the MORB near the spreading centre.

Fig. 2.17. a) Al2O3-SiO2-Fe2O3 diagram showing distinct clusters for different pelitic

formations of the western IOG belt (After Saha, 1994). b) REE patterns of banded iron

formation (BIF) and associated rocks of Western IOG belt (after Majumder et al., 1982). Note


P a g e | 4 9

precise geochronological data obtained from the dacitic lava occurring just below the BIFs

of southern IOG around Daitari yielded 3506.8 ± 2.3 Ma precision U–Pb SHRIMP zircon

age (Mukhopadhyay et al., 2008). Basu et al., (2008) reported ca.3.4 Ga U–Pb zircon LA-

ICPMS age of volcanic rocks of the western IOG belt and opined that all the three IOG

belts are of same age. These two recently obtained precise ages warrant major modifications

in the Precambrian stratigraphy of SC (Mukhopadhyay et al., 2008) and suggest that the

greenstone successions of southern and western IOGs are older than the OMTG and

Singhbhum Granitoids. Acharyya, (1993; 2010a and b) suggested that IOGs are probably

equivalent to smaller enclaves of metasedimentary and metavolcanic rocks of OMG, based

on similar lithologies and low grade metamorphism.

2.3.4 Basic volcanics: Jagannathpur Lava, Malangtoli Lava, Ongarbira and Simlipal

metavolcanics, Dalma and Dhanjori metavolcanics

The western part of the SC was exposed to two extensive basic volcanisms, viz., the

Jagannathpur and the Malangtoli Lavas (Sarkar and Saha 1962; Banerjee 1982; Saha 1994)

which are otherwise known as Dangoaposi lava (Dunn, 1942 and Banerjee, 1982) or

Nuakot volcanic (Iyengar and Murthy, 1982), respectively. They occur close to the western

BIF-bearing IOG belt as flat lying, apparently undeformed lavas (Fig. 2.17a). They are

basaltic andesite in composition (Bose, 2000) and are distinctly younger to SG and overlain

by undeformed clastic and carbonate succession of Kolhan Group or equivalent sediments

and suffered low grade metamorphism (Saha, 1994). Malangtoli lavas show partly altered

plagioclase, both ortho- and clino-pyroxenes in association with interstitial quartz. They

were classified as basalts and basaltic andesite having Mg-numbers range from 51 to 65

(Bose, 2000) and are comparable to high P2O5-TiO2 (HPT) type evolved continental basalts

(Wilson, 1989; Saha, 1994; Bose, 2000) (Fig. 2.17c). Jagannathpur Lava comprises about

30 flows and show relatively wider compositional spread (Alvi and Raza,1992) with Mg #

spreading from 33.5 to 63.7 (Bose, 2000). Malangtoli lavas are believed to be less evolved

than Jagannathpur lavas and pillowed picritic lava occurrence was reported from Namira

lying between these two lava fields.

A few geochemical comparisons between western IOG belt basalts and

Jagannathpur lavas were attempted. Jagannathpur Lava is higher in total REE (132 ppm)

and exhibits more fractionated pattern [(Ce/Yb)N of 8.3] than that of western IOG basalts

[mean total REE 65 ppm and (Ce/Yb)N range 3.2 - 4.1]. Significantly higher LREE


P a g e | 5 0

enrichment and higher Th content (av. 6.7 ppm) compared to western IOG belt basalt (Th:

1.30-2.60 ppm) suggest that the Jagannathpur Lava (and also Malangtoli Lava) is more

enriched than western IOG belt lavas (Bose, 2009) (Fig. 2.17d).

Saha (1994) believed that the Jagannathpur and Malangtoli volcanics are

Paleoproterozoic in age and equivalent to the Dalma Volcanics. Sengupta et al. (1997),

however, included the Jagannathpur and Malangtoli volcanics as the extension of the

western IOG belt mafic volcanics. Geochronological data suggest that the Jagannathpur

Lava (~2.25 Ga Rb-Sr whole rock Pb-Pb isochron age) are much younger than the IOG

(~3.30 to 3.16 Ga; 3.51Ga) and their undeformed nature, absence of pyroclastics, no

evidence of sub-marine eruption and continental tholeiitic nature suggest an anorogenic

setting (Saha, 1994; Misra and Johnson, 2005). However, having no age data available for

Malangtoli Lavas, it was considered equivalent to the Jagannathpur Lava on the basis of

the Kolhan sediments having unconformable common basement-contact with Jagannathpur

Lava in the north and Malangtoli lava in the south (Saha, 1994) (Fig. 2.17a). Saha (1964,

1994) also demonstrated flat-lying gentle warping of the Malangtoli lavas over the highly

folded IOG supracrustal rocks in favour of his conclusion. However, lack of

geochronological data, presence of highly asymmetric folding observed in Malangtoli

flows at places and physical proximity of the basic lavas of western IOG belt without

observable unconformity contact in its southern end need further study to ascertain the

stratigraphic constraints of Malangtoli Lavas. Our Recent geochronologic data from the

siliciclastics overlying the Malangtoli Lava clearly indicate a >3.0 Ga age of the

unconformity (Mukhopadhyay et al., 2014) and thus strongly support that the Malangtoli

Lava to be stratigraphic equivalent of the southern and western IOG basic lava.

Simlipal volcano-sedimentary basin representing a large oval-shaped undeformed

basin (Iyengar and Banerjee, 1964) at the eastern part of the SC overlies the SG, IOG and

Nilgiri Granite and intruded by a gabbro-norite-anorthosite-ultramafic body and the

Mayurbhanj Granite (Saha, 1994) (Fig. 2.3). The sequence begins with a basal arkosic

orthoquartzite (locally conglomerate), followed by three alternate bands of basic volcanics,

separated by two intertrappean orthoquartzite bands. The volcanics are spilitic lavas and

tuffs are intruded by sills and dykes of quartz dolerite with a centrally occurring

differentiated sill, named as Amjori Sill (Iyengar and Banerjee, 1964; Saha, 1994).

In the northwestern part of the SC, another volcano-sedimentary succession namely,

the Ongarbira volcani-sedimentary metamorphosed rocks exist which unconformably

overlie the Chakradharpur Granite and the SG (Fig. 2.18a). Mafic (tholeiitic basalts–


P a g e | 5 1

ultramafic pyroxenites) volcanic rocks, felsic volcaniclastics (tuffaceous metasediments)

and low-grade pelites constitute the Ongarbira volcano-sedimentary succession

(Mukhopadhyay et al. 1990; Blackburn and Srivastava, 1994). The succession thought to

be in comparable structural continuity with the Dalma–Chandil succession at the immediate

north, whose continuity is disrupted by the attenuation and faulting on an intervening fold

limb (Mukhopadhyay et al. 1990; see also Acharyya 2003, pp. 22–23 and Mazumder,

2012). Compositionally, part of Ongarbira volcanics is comparable to MORB-like Dalma

basalt with depleted ocean-ridge type signature but other members are considerably

evolved and remarkably iron enriched. Ongarbira lavas are suggested to be the part of

Dalma volcanism developed under the same regional extensional tectonic setting (Bose,

2009) and lack of calc-alkaline character suggests absence of island arc setting (Raza et al.,

1995).

In the northern and northeastern part of the SC, two major volcano-sedimentary

successions are exposed, viz., Dalma Group and Dhanjori Group. Dalma metavolcanic

succession in the north of the craton overlies Singhbhum Group (Fig.2.18a) and begins with

shale-phyllite, carbon phyllite - tuff with interlayered volcanics, followed upward by

extensive ultramafic volcanoclastics, basic agglomerates and intrusives of komatiite with

some intertrappean beds within Dalma basic volcanics and some felsic volcanic (Bose,

1994; Gupta and Basu, 2000; Saha, 1994). Saha ( 1994 ) suggested Dalma as an

intracratonic riftogenic volcanism which divided the earlier deposited supracrustals of a

single continuous marine basin into two sectors, on either side of this belt, as two

Formations (viz., a lower Chaibasa Formation and upper Dhalbhum Formation) of

Singhbhum Group, while, others considered it as a suture zone and the supracrustals to the

north and south of the volcanic belt belong to different provenances ( Sarkar, 1988 ).

Gupta et al. (1980) considered it as volcano-sedimentary greenstone belt deposited in a

graben formed due to stretching of Archean Proto-continental crust. Dalma volcanic suite

ia also viewed as ophiolitic assemblage marking the collisional zone between Singhbhum

microplate in the south and Chotanagapur block in the north (A. N. Sarkar, 1982 and 1988).

REE pattern with a resultant convex upward chondrite normalized pattern suggests typical

of asthenospheric source for komatiitic lava (Cattell and Taylor, 1990; Das et al. 2001)

(Fig. 2.18c), while the pillow basaltic lavas of Dalma subaqueous volcanic above

(Chakraborti and Bose, 1985) exhibit REE-depleted type pattern typical of modern K-poor

midoceanic ridge basalts (MORB) with considerable Th-enrichment suggestive of a rift

magmatism formed in suprasubduction zone environment (Bose, 1994) ( Fig.2.18b and c).


P a g e | 5 2

Fig. 2.17. a) Geological Map of the western part of Singhbhum Craton showing distribution of

volcanic successions of Malangtoli lavas, Jagannathpur lava and western IOG basin lavas

(modified after Saha, 1994). b) MgO-FeO(t)-(Na2O+K2O) diagram shows plots of Jagannathpur

Lava, Malangtoli Lava and basic volcanics of eastern, western and southern IOG belts. Note

that the plots of basic volcanics of WIOG and SIOG belts are completely overlapping and cluster

in a separate field showing distinctly lower FeO and MgO content than those of eastern IOG

belt. Jagannathpur Lava show somewhat dispersed plots yet distinct Fe-enrichment with a

considerable overlap with basic volcanics of WIOG and SIOG belts. Malangtoli lava show clear

tholeiitic trend. c) Plots in TiO2-K2O-P2O5 diagram (after Pearce et al., 1977) show continental

tholeiitic character for both Jagannathpur and Malangtoli Lavas. However, Malangtoli Lavas

are slightly higher in TiO2 content than normal continental tholeiite. d) Chondrite-normalised

[Taylor and McLennan (1987)] REE patterns of mafic lavas of WIOG belt (green line) and

Jagannathpur Lava (blue line). LREE enrichment and higher REE fractionation for Jagannathpur

Lava than those of WIOG mafic lavas (data Bose, 2009).

Fig. 2.18. a) Geological Map of the western part of Singhbhum Craton showing distribution of

volcanic successions of Malangtoli lavas, Jagannathpur lava and western IOG basin lavas

(modified after Saha, 1994). b) MgO-FeO(t)-(Na2O+K2O) diagram shows plots of Jagannathpur


P a g e | 5 3

In the northeastern part of the craton, adjacent to the south of the SSZ, Dhanjori Group

volcano-sedimentary succession overlie the Archean SG and IOG rocks (Sarkar and Saha,

1962, 1963; Sarkar et al.,1977; Saha, 1994) (Fig. 2.18a). Dhanjori Group includes quartzite

and metapelite in the lower horizon, followed by mafic and ultramafic tuffs and intrusives,

and tholeiitic lavas upward (Dunn and Dey, 1942; Gupta et al. 1985; Saha, 1994). Dhanjori

volcanics follow a Komatiite-Tholeiite trend of Viljoen and Viljoen (1969) and suggested

to be derived from upper mantle where undepleted mantle material were present (Saha,

1994) (Fig.2.19d). The lower ultramafics have distinct komatiitic affinity with definitive

spinifex textures (Viswanathan and Sankaran, 1973; Gupta et al. 1985; Majumder, 1996)

which is, however, disagreed by Bose (2009). Dhanjori lavas are tholeiites (Dunn and Dey,

1942), basalt to basaltic andesite (Alvi and Raza, 1992), with spilitic affinity (Iyengar and

Alwar, 1965) with minor normative nepheline in some flows (Bose, 2000). Saha (1994)

considered the Dhanjori group as older than the Mayurbhanj Granite, without any reported

intrusive relationship of Mayurbhanj Granite into Dhanjori volcanic (Misra, 2006).

Dhanjori Group is considered younger than Chaibasa Formation of the Singhbhum Group

with overthrusted contact ( Dunn and Dey, 1942; Sarkar and Saha, 1977), while the others

believe in normal northward younging of Dhanjori Group with Singhbhum Group and

Dalma rocks, thus Dhanjori is older than Chaibasa Formation (Sarkar and Deb, 1974;

Mukhopadhyay, 1976; Mazumder et al., 2012). The sediments of Dhanjori formation are

considered terrestrial alluvial-fan deposit, known as Dhanjori Formation and are

conformably overlain by the marine Chaibasa Formation further northward marking a

sequence boundary (Mazumder 2005; Mazumder et al. 2012).

Geochemical similarities between the Dalma and the Dhanjori Lavas and structural

studies prompted Saha (1994) to suggest that the Dhanjori Group is nearly

contemporaneous with the Dalma Volcanics and therefore, younger than the Chaibasa

Formation. Bose (2000) inferred that they are geochemically dissimilar yet stratigraphically

equivalent. Sinha et al. (1997) drew equivalence between the IOG and the Dhanjori Group,

on the basis of the occurrence of the Quartz-Pebble Conglomerate (QPC) containing detrital

uraninite and pyrite and inferred that both the supracrustals overlie the SG with an erosional

unconformity and are overlain by the Singhbhum Group. This stratigraphic modification

contradicts the intrusive field relationships of the SG III into the IOG supracrustals (cf.

Saha, 1994). Moreover, radiometric age data also disproves such contention which

indicates that the Dhanjori supracrustals (~ 2.80 Ga, Misra and Johnson, 2005, 2.6–2.1 Ga,


P a g e | 5 4

Fig. 2.18. a) Geological Map of northern part

of Singhbhum cratonic province showing

disposition of Dalma lavas, Dhanjori lavas,

Ongarbira volcanics and northern tip of

Jagannathpur lavas (modified after Bose,

1994). b) Primary mantle-normalised (Sun &

McDonough, 1989) multi-elemental spider

diagram shows depleted nature of Proterozoic

Dalma volcanics compared to Archean OMG

amphibolite. OMG amphibolite is remarkably

enriched in LILE with flat HFSE (Saha, 1994).

Dalma basalts are characteristically Th-

enriched. Spider diagram of >3.0Ga basalts (after Condie, 1990) also shown for comparison (after Bose, 2009). c) Chondrite-

normalised (Taylor & McLennan,1987) REE pattern for Dalma volcanics show LREE

depletion and convex upward pattern suggesting asthenospheric source for komatiitic

lava (Cattell and Taylor, 1990; Das et al., 2001), while basaltic lavas show REE-

depleted type typical of K-poor MORB. d) CaO-MgO-Al2O3 ternary plots of Dhanjori

volcanics show Komatiite-Tholeiite trend of Viljoen and Viljoen (1969) (data after

Saha, 1994).


P a g e | 5 5

Acharyya et al., 2010) are younger than the IOG (~3.30-3.16 Ga, Misra,

2006;3.4Ga, Basu et al., 2008, or up to 3.51 Ga, Mukhopadhyay et al., 2008). There is no

consensus on the age of the Dhanjori siliciclastics. Recent geochronology data from detrital

zircon and from zircons from the granites intruded on the lower parts of the Dhanjori Group

it has been suggested that Dhanjori sedimentation dates back to >2.8 Ga (Acharyya et al.

2010b) and might have extended into Paleoproterozoic.

The Simlipal and Jagannathpur successions (and Malangtoli Lavas) were correlated

with the Proterozoic Dhanjori succession, based on lithostratigraphy alone (Sarkar and

Saha, 1962; 1977; Goodwin, 1996). Precise geochronological studies, detailed

sedimentological and stratigraphic analyses are critical to resolve the controversy over the

depositional and tectonic setting of Jagannathpur, Malangtoli, Simlipal successions of

southern part of the craton and their correlation with the northern volcano-sedimentary

successions like Dhanjori and Dalma successions.

2.3.5 North Singhbhum Mobile Belt and associated supracrustals: Singhbhum Group,

Darjing Group, Kunjar basin and Gangpur Group

Over the Archean greenstone-granitoid cratonic terrain, the North Singhbhum Mobile Belt

(NSMB) supracrustals (known as Singhbhum Group) was deposited with an erosional

unconformity with SG in the north and Bonai Granite in west, Nilgiri Granite in the

southeast and the older member of Chakradharpur Granite Gneiss in the northwestern part

of the SC (Bandyopadhyay and Sengupta, 1984; Saha, 1994; Sengupta et al. 1991) (Fig.

2.3 and 2.18a). The boundary of the NSMB supracrustal belt with the SC to the south is

marked by about 200 km long linear Singhbhum Shear Zone (SSZ). The shear zone

gradually grades into a high angle gravity fault towards west and northwest and continues

further to the western margin of the Bonai Granite where the supracrustals lie over older

IOG rocks along the faulted contact (Saha, 1994; Mukhopadhyay, 2001). Another shear

zone, known as the Northern Shear Zone, occurs sub-parallel to the northern boundary of

the NSMB.

The stratigraphic relationships between different units within NSMB is extensively

obliterated by the crustal scale lineament, known as Singhbhum Shear Zone (SSZ). The

lower part of the NSMB includes the Dhanjori Group with Dhanjori siliciclastics and

Dhanjori volcanics. The upper part includes the Singhbhum Group and the Dalma

Volcanics. The Singhbhum Group includes mainly pelitic and semipelitic schists, quartzites

and locally para-amphibolites, metamorphosed felsic to intermediate tuffs and mafic sills.


P a g e | 5 6

The stratigraphic relationship between the Singhbhum and Dhanjori Groups remains

debatable due to the deformation in the SSZ. The Singhbhum Group is divided into lower

Chaibasa Formation and upper Dhalbhum Formation (Sarkar and Saha, 1962). Chaibasa

Formation contains marginal marine fine-grained sandstone, sandstones-shale heterolithic

units and shales (Bhattacharya, 1991; Bose et al., 1997; Bhattacharya and Bandyopadhyay

1998). The sandstones were interpreted to be formed in a subtidal setting, whereas the

heterolithic units and the shales were deposited in a shelf setting below and above storm

wavebase respectively (Bose et al., 1997; Mazumder, 2005; Mazumder et al., 2009). In

contrast, the overlying Dhalbhum Formation represents fluvial sedimentation displayed by

medium to coarse, ill-sorted, mineralogically immature sandstones with fining upward

cycle (Mazumder 2003, 2005; Mazumder et al., 2012). There is no unequivocal age data

for the NSMB supracrustals. Based on the age of the acid volcanic in the Dalma Volcanics

a Mesoproterozoic age has been suggested (Saha, 1994).

In further west of the western IOG and the Bonai Granite, the SC is extended by

geosynclinal successions of Darjing Groups and Gangpur Group (Mahalik, 1987) (Fig. 2.3).

An approximately 200 m thick siliciclastic succession, called Birtola Formation (Mahalik

1987) overlies the western IOG rocks of 3.4 Ga age (Basu et al., 2008) and the Bonai

Granite of 3163 Ma age (Sengupta et al. 1991). Mazumder (1996) in his Geological Map

of SC grouped these rocks as IOG metasediments of ‘Iron Ore Barren Province’, as they

are devoid of major iron ore formation (Fig 2.3). The Birtola Formation forms the

lowermost lithostratigraphic unit of the three-tier Darjing Group. The Birtola Formation

comprises basal and interlayered polymictic conglomerate with clasts of granites, rafts of

BIF and other IOG components and arkosic sandstones. The middle Kumakela Formation

characterizes carbonaceous phyllites and minor quartzite units and upper Jalda Formation

displays dominantly metamorphosed thick calc-argillaceous sediments and quartzite

(Mahalik 1987; Kundu and Matin 2007) (Fig. 2.19a). Prasad Rao et al.(1964) recognised

six sequences out of which rocks lying between Gangpur Group and the Bonai Granite are

subdivided into three sequences. Ramachandran and Raju (1982) grouped the rocks

between Rourkela and Bonai, into four groups (Group I, II, III and IV) of which Group II

corresponds to the Birtola Formation of Mahalik (1987) and Group III to the upper two

formations of Darjing Group (Kumakela and Jalda Formations) of Mahalik (1987). Later,

rocks constituted by Sequence I and V of Prasada Rao et al. (1964) and corresponding

Groups I and II of Ramachandran and Raju (1982) and parts of IOG and Birtola Formation

of Mahalik (1987) were grouped together as Chandiposh Group with six formations (Naik,


P a g e | 5 7

2001) ( Table 2.7). Birtola Formation have been intruded by the 2809±12 Ma Tamperkola

Granite (207Pb/206Pb age of zircons) hence, inferring Birtola Formation older than 2800 Ma

(Bandyopadhyay et al. 2001). Saha et al. (2004) provided Sm-Nd model age of ~3.6 to 4.0

Ga for Birtola sandstone and demonstrated that the sandstone represents bimodal

mechanical mixture of OMG and OMTG and strong Nb-Ta depletion relative to primitive

mantle, low Nb/Ta and high Zr/Sm ratios and REE patterns suggestive of subduction-

related magmatic arc sources identical to Archean tonalite-trondhjemite sources (Fig.

2.19d).

The sub-circular basin-shaped quartzite outcrops, named as the Kunjar Group,

(Sequence VI of Parsada Rao et al., 1964) exposed to the southwest of Darjing Group of

rocks are considered as the youngest sequence in the Rourkela-Bonai area and is considered

equivalent to Kolhan Group (Iyengar and Murthy, 1982; Mahalik, 1995) (Table 2.7). The

Kunjar Group includes immature to mature arenaceous rocks, minor phyllites with a few

intervening basic volcanic and the sequence overlies the Tamperkola Granite (with a

faulted contact) and unclassified granite (locally called as Bamra Granite, by Chaki et al.,

2005) in the south while in the north near Tamra village, it overlies the Darjing Group of

rocks (Mahalik, 1987) (Fig. 2.19a). However, no age data is available for these rocks to

support its stratigraphic status. Moreover , lithological similarities, effect of at least two

phases of deformation and physical continuity of these rocks in the northeastern part of the

basin (Near Hatichappar area) with the Birtola Formation of Darjing Group raises question

on the conclusion of Kunjar rocks to be equivalent to Kolhan equivalent as postulated by

Ramchandran and Raju (1982).

To the further north of Darjing Group, Gangpur Group of pelitic, psammitic and

calcareous metasediments in a geosynclinal basinal setting occur to the north of Rourkela

over ENE-WSW trending elongated stretch of 144 km by 15 km area and is bounded by

IOG rocks in the east and southeast and Gondwana sediments to the south (Fig. 2.3 and

2.19a). Krishnan (1937) considered that the Gangpur sediments to be older than adjoining

IOG, while Dunn and Dey (1942) inferred that they are occurring between ‘Iron Ore Series’

and the Chaibasa Formations. Banerjee (1967) interpreted a regional refolded reclined fold

with an inverted stratigraphy in the upper tectonic level. Kanungo and Mahalik (1975)

revised the stratigraphy suggesting a conglomerate (Raghunathpalli Stage) at the base of

Gangpur Group with the IOG rocks unconformably lying below it. Sarkar et al. (1996)


P a g e | 5 8

d) Birtola sandstone plots in Nb/Ta vs. Zr/Sm diagram cluster in Archean TTGs, away from

modern day IAB. Birtola plot (red dots) away from the modern continental crust field possibly

due to higher concentration of heavy minerals like zircon in the sandstone (Saha et al., 2004).

Fig. 2.19. a) Geological Map of Darjing Group,

Kunjar succession and Gangpur Group, west of

Bonai Granite (redrawn after Mahalik, 1987).

Tamperkola Granite has partly tectonized contact

with Kunjar rocks. b) Modal QFL and QmFLt

diagram suggests Birtola sandstones are derived

from continental block provenance. Dashed

arrow indicate potential positions of the

sandstones in recycled orogen field if

pseudomatrix is recalculated in lithic fragments

(data Saha et al., 2004). c) REE patterns of Birtola

sandstones (Dark red lines) displaying LREE

enrichment, flat HREE with absence of Eu-

anomaly identical to Archean sandstones and 3.3

Ga old tonalites and amphibolites (in inset).


P a g e | 5 9

suggested 850 Ma as the age of Gangpur Orogeny and metamorphism based on intrusive

800- 900Ma old (whole rock Rb-Sr isochron age) peraluminous monzogranites from the

southwestern part of the Gangpur metasediments (viz., at Ekma, Itma and Timna areas).The

age of Gangpur orogeny are tectonically equated with the Satpura Orogeny (900 Ma)

although Gangpur rocks are spatially separated from the latter (Mookerjee et al., 2000).

2.3.6 Younger Granites: Kuilapal Granite, Arkasani Granophyre, Soda Granite,

Chakradharpur Granite, Mayurbhanj Granite, Ekma, Itma and Timna Granites

The Kuilapal Granite (KG) occurring over 80 sq km area with an elliptical outline and lies

in the northeastern part of the NSMB. It is a medium to coarse grained gneissic rock with

injection gneiss containing extensive assimilation of surrounding schists of Singhbhum

Group (cf. Dunn and Dey, 1942). The granite gneiss is largely granodioritic in composition

Jones

(1934)

Krishnan

(1937)

Prasada

Rao

et al.

(1964)

Sarkar,

Saha and

Miller

(1969)

Ramchandran

and Raju

(1982)

Mahalik

(1987)

Chaudhuri

and

Pal (1983)

After Naik

(2001)

Iron Ore ‘Series’

(Group)

Gangpur

‘series’

(Group)

unconformity

Sequence

VI

Gangpur

Group

unconformity

Group-IV

(Gangpur Group

≡ Kunjar Group ≡ Kolhan group)

unconformity

Gangpur Group

unconformity

Gangpur

Group

Conformable (gradational)

Tamra

Formation

(Gangpur Group)

Tamperkola

Granite

Iron Ore

‘Series’

(Group)

Dhalbhum

Formation of

Singhbhum Group

Group III

unconformity

D

A R

J

I

N

G

G R

O

U

P

Jalda

Formation

Kumakela

Formation

Lower part of

Gangpur

Group

Bhaliyadihi

Formation

Soldega

formation

Madhupur

Formation

Sequence V

Group II

(equivalent to Dhanjori Group)

unconformity

Birtola

Formation

unconformity

Birtola

Formation

Nalghati

Formation

Gurundia

Formation

Bonai Granite

Sequence I

(older than

IOG) –

enclaves in Bonai

Granite

Group I (part of

IOG) – intruded

by Bonai

Granite

Rocks intruded by

Bonai Granite

(part of IOG)

Lahunipara

Formation

(all units are

intruded by Grey Bonai

Granite)

Sequence

IV (IOG)

IOG

Table 2.7. A comparison of stratigraphic successions proposed by different authors for

supracrustal belts exposed to the west and north of Bonai Granite. Table 2.8. A comparison of stratigraphic successions proposed by different authors for supracrustal

belts exposed to the west and north of Bonai Granite.


P a g e | 6 0

with oligoclase-andesine (An20-An40) as the dominant feldspar. However, the composition

of the gneiss ranges widely from trondhjemite through granodiorite, adamellite to granite

proper (Dunn and Dey, 1942).

The Arkasani Granophyre lies in E-W elongated zone north of Chakradharpur

Granite intrusive within the NSMB and occurs as seven small isolated granitic bodies by

Dunn (1929) (Fig. 2.18a). It is a medium to coarse grained rock with euhedral phenocrysts

of plagioclase (An22-An35) within the groundmass of more sodic plagioclase (An2-An15),

K-feldspar, biotite and muscovite. The accessory minerals include tourmaline, zircon,

epidote, apatite, magnetite and sphene. Modal and normative Or-Ab-An diagram plots

compositionally lie Granite field close to younger pegmatitic granodiorite-granite

component of Chakradharpur Granite (CKPG-II) (Chottopadhyay, 1990) with strong Sr-

depletion (Rb/Sr ranges from 0.95 to 7.56, av. 2.6) and abnormally high Ba content (Table

2.8). Slightly fractionated REE pattern (CeN/YbN: 1.52-9.49), with moderate to large

negative Eu-anomaly (Eu/Eu*: 0.34-0.58; av. 0.465) and HREE enrichment (TbN/LuN :

23.3-48.9) (Sengupta et al., 1983). Petrographic and geochemical similarities of Kuilapal

Granite and Arkasani Granophyre situated at the north and south of Dalma volcanics

respectively prompted authors to infer an origin from a shallow-level fractional

crystallisation of a crustally-derived granodiorite melt. Dominance of xenoliths in the

Kuilapal granite suggests large-scale assimilation of crustal rocks (Sengupta et al., 1994).

A number of small bodies of feldspathic schist and Soda Granite occur along and at

the close vicinity of SSZ in the eastern and central part (Dunn, 1937; Dunn and Dey, 1942;

Saha, 1994). Feldspathic schists are highly cleaved, mylonite containing K-feldspar,

plagioclase phenocrysts and quartz grains granulated and highly strained with biotite flakes.

Soda granites are inequigranular rock with quartz and plagioclase (An9-An15) together with

minor minerals like chlorite, biotite, epidote, tourmaline, muscovite, magnetite, amphibole,

apatite and zircon. Rock exhibits porphyroblastic to granoblastic texture. Normative plots

display trondhjemitic to granitic nature. REE pattern of Soda Granite simulates those of

Arkasani Granophyre with a general depletion in total REE for soda granite and suggests

an overall crustal source (Saha, 1994). Different hypotheses were put forward for the origin

of Soda Granite which include magmatic origin from late magmatic soda-rich residual

liquid (Dunn, 1937; Viswanathan, 1961; S. C. Sarkar, 1964), sodic residual magma

replacing a partially recrystallized potassic granite (Dunn and Dey, 1942), migmatitic

origin by progressive replacement of Shear zone schists (Banerji and Talapatra, 1966;

Banerji et al., 1972) and metasomatic or mixed origin (Sarkar et al., 1986). Similar REE


P a g e | 6 1

patterns of Soda Granite, Arkasani Granophyre and CKPG-II, lying along the Singhbhum

Shear Zone, indicate similar origin of Soda Granite by partial melting of crustal rocks in

the subducting sub-plate at the intraplate subducting zone with varying degree of country

rock assimilation (Saha, 1994).

The Chakradharpur Granite Gneiss (CKPG) (Dunn, 1929; Sarkar and Saha, 1962;

Saha et al., 1984; Bandyopadhyay, 1981, 1983; Bandyopadhyay and Sengupta, 1984;

Sengupta et al., 1983) occurs as isolated body intrusive into Singhbhum Group and is

exposed along the northern, eastern and northwestern margins of the craton (Fig. 2.3 and

2.18a). CKPG is outlined by the two bifurcated arms of SSZ running in E-W direction along

the northern and southern boundaries of CKPG. This granite gneiss comprises an older

trondhjemite gneiss (CKPG-I) forming basement to the overlying Singhbhum Group and a

younger pegmatitic granodiorite-granite unit (CKPG-II), intrusive into the older gneiss as

well as enveloping supracrustals. Geochemically, the older trondhjemite gneiss is

considered equivalent to the SG-I or II, whereas CKPG-II is equivalent to the younger

granite plutons (e.g. Arkasani Granite and Mayurbhanj Granite) occurring within the

Singhbhum Group (Saha, 1994). On geochemical observations, CKPG-I is considered

comparable with OMTG and CKPG-II with SG Type-B by Sengupta et al. (1988) which

Saha (1994), however, disagreed on the basis of modal composition, major oxide and REE

patterns.

Rb-Sr isotopic data on Soda Granite provided isochron ages of 1677±11Ma (with

initial Sri = 0.7314±0.003), 1633±6 Ma (with initial Sri = 0.7449±0.009) (Sarkar et al.,

1986) and Pb-Pb isochron two-stage model age provided 2220Ma and 2017 Ma. While

those of Kuilapal Granite are 1638 ± 38 Ma (with Sri= 0.72173 ± 0.00156 (MSWD=11.3)

and Arkasani Granophyre 1052±84 Ma (Sengupta et al., 1994). The older data indicate

emplacement age of 2220 Ma followed by a younger event of evolution around 2017 Ma.

The wide spread Rb-Sr age of 1633-1677 Ma suggestive of main metamorphic episode in

the belt. High Sr-initial values indicated partial melting of either older crustal rocks or pre-

existing sediments.

The irregular, rough crescent-shaped granitic batholiths exposed in the south of

Dhanjori basin and the southern periphery of Simlipal area in the eastern margin of the SC

is named as Mayurbhanj Granite (MG) by Saha (1975). It is situated east of SG and

intrusive into the latter. MG comprises of three units, 1) fine-grained granophyric biotite-

hornblende-alkali feldspar granite, 2) coarse grained well foliated ferruhastingsite-biotite

granite , intrusive into the above unit and, 3 ) biotite aplogranite intrusive into the unit 2


P a g e | 6 2

(Saha et al., 1977) whose mean chemical values are given in Table 2.9. It is a K-rich granite

whose REE pattern shows LREE enrichment, flat HREE with conspicuous negative Eu-

anomaly indicating low degree of fractionation (CeN/YbN =4.95).

Average

Kuilapal

Granite

(n=1)

(after Dunn

& Dey,

1942)

Chakradharpur Granite

(after Sengupta et al., 1983)

Mean of Arkasani

Granophyre

(n=10)

(after Sengupta et

al., 1983)

Soda Granite

(n =15)

(after Saha et al.,

1968; compilation by

Saha, 1994)

CKPG –I

(n= 6)

CKPG-II

(n=4)

%

SiO2 73.40 69.22-73.88

(71.38)

71.80-74.42

(72.62) 68.94

68.96-74.24 (71.97)

TiO2 Trace 0.05-0.18 (0.22) 0.19-0.38 (0.32) 0.74 0.50-1.24 (0.68)

Al2O3 12.83 12.92-15.88

(14.80)

12.53-14.89

(13.69) 14.17

9.66-13.89 (12.88)

Fe2O3 1.25 0.42-4.36 (1.99) 1.04-3.36 (2.15) 4.03 0.82-3.61 (2.06)

FeO 2.12 -- -- -- 0.77-6.46 ( 3.02)

MnO 0.09 0.01-0.08 (0.03) 0.03-0.04 (0.035) 0.06 Trace-0.14 (0.06)

MgO 0.14 0.16-1.19 (0.82) 0.19-0.76 (0.46) 1.61 0.50-1.58 (0.77)

CaO 0.91 0.80-2.14 (1.35) 0.96-1.68 (1.23) 1.32 0.22-2.84 (1.42)

Na2O 3.70 4.92-8.41 (6.07) 3.80-5.15 (4.51) 3.77 2.12-5.51 (4.46)

K2O 4.80 0.52-2.62 (1.64) 2.80-4.20 (3.6) 4.65 0.36-3.68 (1.50)

P2O5 0.01 0.03-0.16 (0.10) 0.06-0.16 (0.10) 0.09 0.03-0.33 (0.15)

LOI 0.69 -- -- -- --

ppm

Ba -- 64-790 (311) 200-560 (338) 1104 60-405 (244)

Rb -- 15-43 (33) 64-119 (87) 83 50-510 (156)

Sr -- 119-386 (280) 58-181 (118) 31.8 135-235 (184)

Ga -- -- -- -- 10-21 (15)

Zr -- -- -- -- 98-525 (243)

Y -- -- -- -- 40-112 (71)

Th -- -- -- -- --

U -- -- -- -- 5-9 (7.5)

Cr -- -- -- -- 1-15 (6)

Ni -- -- -- -- 12-71 (32)

Co -- -- -- -- 6-16 (11)

V -- -- -- -- 17-67 (37)

Cu -- -- -- -- 4-122 (29)

Pb -- -- -- -- 10 (10)

La -- 5.10-86.00

(41.18)

16.50-250.00

(89.25) 54.6

--

Ce -- 7.70-108.00

(55.12) 27.90-113.00 (53)

102 --

Pr -- -- -- -- --

Nd -- 11-44 (27.5) 13-51 (28) -- --

Sm -- 0.40-5.30 (3.03) 2.20-8.50 (4.06) 9.5 --

Eu -- 0.27-1.69 (1.12) 0.296-1.25 (0.75) 1.20 --

Gd -- -- -- -- --

Tb -- 0.12-0.34 (0.22) 0.431-0.93 (0.58) 1.48 --

Yb -- 0.09-0.76 (0.39) 1.23-5.70 (2.39) 5.68 --

Lu -- 0.036-0.67

(0.165)

0.199-1.06 (0.434) 0.9

--

∑REE -- -- -- -- --

Eu/Eu* -- 1.12-2.42 (1.80) 0.39-1.20 (0.695) 0.465 --

(Ce/Yb)N -- 14.66-48.07

(28.86)

4.05-7.11 (4.97) 1.52 - 9.49

--

(Tb/Lu)N -- -- -- 23.3-48.9

Table 2.8. Major oxide and trace elemental chemical analysis data of younger granites

exposed in Singhbhum cratonic area and in North Singhbhum Mobile Belt. Numbers in

parentheses are the mean values.

Table 2.9. Major oxide and trace elemental chemical analysis data of younger granites

exposed in Singhbhum cratonic area and in North Singhbhum Mobile Belt. Numbers in

parentheses are the mean values.


P a g e | 6 3

Geochemically, it is similar to the youngest components of both SG and Bonai

Granite and correlatable with the two small plutons exposed near Nilgiri and Romapahari

area. Mayurbhanj Granite displays typical characteristics of A-type granite (Misra and

Sarkar, 1991) and within-plate Granite tectonic setting (Saha, 1994) which is very rare for

Proterozoic granite (cf. Whalen et al., 1987). On the basis of 2084 ±70 Ma Rb-Sr whole-

rock isochron date (Iyengar et al., 1981), Mayurbhanj Granite is considered as

Paleoproterozoic in age (Saha et al., 1984; Saha, 1994). The granites from Nilgiri yielded

2366 ± 126 Ma Rb-Sr age and highly deformed granite from Romapahari area yielded 1895

±46 Ma Rb-Sr age (Vohra et al., 1991). High initial 87Sr/86Sr ratios of these granites suggest

long crustal residence time. Isotopic studies on zircon grains (207Pb/206Pb dating) yielded

two groups of zircon population with 3080±8 Ma and 3092±5 Ma ages indicating coeval

emplacement of Mayurbhanj Granite with SG Phase III (Mishra et al., 1998). Based on this

fact Mukhopadhyay (2001) conjectured that Mayurbhanj Granite is an Archaean unit

involved in the Proterozoic deformation and metamorphism due to its proximity to the

Proterozoic fold belt. The stratigraphic status of Mayurbhanj Granite, thus, remains

uncertain till date.

At the extreme western part of the Gangpur basin, small plutons of undeformed

granitoids near Ekma, Itma and Timna areas intruded into the deformed metasediments of

Average Mayurbhanj Granite(after Saha, 1994)

Granophyric

Microgranite

(n=13)

Coarse

ferrohastingsite

granite

(n=14)

Biotite

ophio-granite

(n=11)

SiO2 74.91 73.74 74.44

TiO2 0.22 0.28 0.37

Al2O3 13.53 13.44 12.48

Fe2O3 1.45 1.31 2.43

FeO 0.83 1.32 1.23

MnO 0.02 0.02 0.04

MgO 0.06 0.19 0.07

CaO 0.45 0.61 0.72

Na2O 3.40 3.70 3.62

K2O 4.39 4.47 4.02

P2O5 0.18 0.16 0.12

LOI -- -- --

Rb 147 113.5 108.9

Sr 34.1 32.5 44.6

Ga 17.6 18.1 17.5

Zr 496.5 351.8 388.2

Y 39.7 40.5 35.0

Th 23.4 28.9 17.0

U 6.4 4.4 4.8

Nb 37.7 42.5 32.2

Cu 12.9 11.2 12.5

Zn 75.3 118.4 103.9

Pb 28.5 31.5 26.5

Rb/Sr 4.31 3.49 2.44

Table 2.9. Mean chemical composition of three units of Mayurbhanj Granite.

Table 2.10. Mean chemical composition of three units of Mayurbhanj Granite.


P a g e | 6 4

Gangpur Group. These meso- to leucocratic granitic plutons represent, beyond doubt, the

youngest thermal event with no imprint of deformation and metamorphism exhibited by

non-foliated granites with hypidiomorphic granular texture. These granites yielded

803±116 to 966±32 Ma Rb-Sr whole rock age reflecting culmination of Gangpur Orogeny

(Mookerjee et al., 2000) correlatable with Satpura Orogeny. The emplacement of these

granitoids mark the end of Precambrian thermal activity in SC.

2.3.7 Intrusive bodies: Newer Dolerite and other ultramafic and gabbro-anorthosite

A set of reticulating basic dyke swarm, called as Newer Doleritic Dykes (NDD) (Dunn and

Dey 1942) traverse the SG pluton, Bonai Granite, Nilgiri Granite, Chakradharpur Granite

gneiss, Arkasani Granophyre and Mayurbhanj Granite. These NNE–SSW to NE–SW, NW–

SE to E–W trending dyke systems intruded granitic plutons and other supracrustals (Dunn

and Dey 1942; Saha 1949, 1994; Saha et al. 1973; Mukhopadhyay 2001; Bose 2008;

Mazumder and Saha 2009), viz., IOG (Saha, 1994) and the OMG rocks (cf. Iyer, 1932;

Saha, 1949). They are mainly quartz dolerite with minor occurrences of norite, microgranite

and syenodiorite (Saha 1994; Mukhopadhyay 2001) and associated ultramafic dykes (Bose

and Goles, 1971; Saha et al. 1973; Saha 1994; Bose 2000, 2008). The dyke swarm marks

the end of cratonization processes in the Singhbhum crustal province when the continental

crust was sufficiently cooled down and became rigid fractured body (Mukhopadhyay 2001;

Bose 2009). Precise geochronological data are inadequate with K–Ar ages yielding a range

from 923 to 2144 Ma age (see Saha 1994 and Mukhopadhyay 2001 for references). Mallick

and Sarkar (1994) suggested three pulses of mafic intrusion for NDD, during 2100±100

Ma, 1500±100 Ma and 1100±200 Ma. Ultramafic members of the dyke swarm yielded

2613±177 Ma Rb-Sr isochron age suggesting the oldest stabilization event of the cratonic

blocks of India (Roy et al., 2004). The genetic relation of the mafic and ultramafic magmas

is not established and requires more studies on petrography and trace element

geochemistry.

A few titaniferous and vanadiferous magnetite bearing intrusive gabbro–anorthosite

ultramafic bodies occur along the eastern margin of the SG pluton from Butgora in the

north to Nausahi in the south (Saha 1994). Their stratigraphic status, petrology and

geochemistry were studied by many workers (Dun and Dey, 1942; Chatterjee, 1945; Saha,

1959; Dasgupta, 1969; Iyengar and Alwar, 1965; Chakraborty et al.,1980; Banerjee,1984)

and found to be older than SG in age and grouped under the basic rocks of the Iron Ore

‘Stage’ ( Dunn and Dey (1942), while others showed that they are intrusive into the SG and


P a g e | 6 5

co-magmatic with granophyres of Mayurbhanj Granite, (Chatterjee, 1945; Sarkar and

Saha, 1962,1963; Iyengar and Alwar, 1965). Saha et al. (1977) further revised that the

gabbros are older than the granophyres. Two petrogenetically different magmas were

envisaged, one related to the ultramafic products and the other to gabbro–anorthosite

emplacements (Deb and Chakraborty 1960; Mondal et al. 2006).

2.3.7 Siliciclastic Successions: Kolhan Group and other unclassified siliciclastic belts

Over the cratonised greenstone-granitoid rocks and the dominantly basaltic flows of

Jagannathpur-Malangtoli Lavas, a Mesoproterozoic succession of epicontinental basinal

sediments, called the Kolhan Group, was deposited in the western flank of the Singhbhum

granitic batholith between Chaibasa and Noamundi area, extending for about 60 km strike

length with an average width of 10-12 km (Saha, 1948; Ghosh and Chatterjee 1994; Saha

1994; Mukhopadhyay et al., 2006; Ghosh et al., 2015) (Fig. 2.3 and 2.20). The Kolhan

Group is largely undeformed and unmetamorphosed with basal purple sandstone-

conglomerate and upper argillaceous limestone with greyish yellow shales unconformably

overlies the SG and the IOG rocks (Saha 1994; Mukhopadhyay, 2001). The eastern margin

of Kolhan sediments has unconformable contact with SG and western faulted contact with

the IOG rocks. The intercalated conglomerate–sandstone units, sheet sandstones and

sandstone–siltstone alternations of the lower part of the Kolhan Group suggests a braided

stream, on a beach and on a wave-dominated shelf environment (Ghosh and Chatterjee,

1994; Bandopadhyay and Sengupta, 2004; Bandopadhyay et al. 2010). Mukhopadhyay et

al. (2006) suggested a Mesoproterozoic age for Kolhan Group for Chaibasa–Jagannathpur

tract on the basis of lithostratigraphic studies. A deep water cratonic palaeogeography for

the type area has also been interpreted. No well-constrained age data is available for

Kolhans. Singh (1998) suggested an age of ~1.0 Ga for the Kolhan Group, while, Saha

(1994) provided K-Ar whole-rock age of ~980 Ma on a poorly metamorphosed Kolhan

shale and ~1.56 - 1.14 Ga for IOG phyllite, overlain by Kolhan sediments thus, constraining

the maximum age of Kolhans to be around ~1.14 Ga.

The stratigraphic status of the poorly sorted clast-supported deformed conglomerate

bodies within pelitic and mafic schists, and directly overlying the Chakradharpur Granite

Gneiss in Rajkharsawan–Chakradharpur area (Bandyopadhyay, 1981; Sarkar, 1984;

Mazumder et al., 2000) is not known. They contain BIF lithoclasts indicating an age

younger than BIF of IOG but whether they belong to Mesoarchean or Paleoproterozoic age

is not well-understood (Mazumder et al., 2012). Another mildly metamorphosed and less


P a g e | 6 6

deformed siliciclastic succession, Nayadih Formation, exposed at the western flank of the

SG, was also assigned post-Archean IOG age based on presence of IOG chert pebbles in

basal conglomerate horizon (Bhattacharya and Mahapatra, 2008). However, its actual age

and correlatibility with other siliciclastic successions of the craton is unknown and warrants

detailed sedimentological, geochronological and stratigraphic studies.

In the southern part of the SC, the stratigraphically ill-defined siliciclastic belts are

exposed along the Chamakpur-Namira-Keonjhar tract of Keonjhar district, Mankarchua

area, situated at the north of Pal Lahara town of Angul district and further southeastern

extension occurring as detached outliers continues along the southern margin of the

southern IOG belt of Jajpur district as Mahagiri Quartzite (Saha, 1994) (Fig. 2.20). The N-

S trending 50 km long succession along Chamakpur-Namira-Keonjhar tract unconformably

overlie the SG and Malangtoli Lavas in the east and has faulted contact with western IOG

belt in the west. The detached siliciclastic outliers in Mankarchua area are vaguely

correlated with the Kolhan Group based on gross lithological similarities (cf. Saha, 1994).

No detail studies on stratigraphy and geochronology for these siliciclastic intervals was

taken up until very recently Mukhopadhyay et al. (2014) reported ~3.01 Ga detrital zircon

U-Pb ages for maximum sedimentation age of these sandstones.

The Singhbhum crustal province portrays almost extensive stratigraphic record

through the Archaean–Proterozoic boundary (Mukhopadhyay, 2001) and thus provides

invaluable information for understanding the Earth’s evolution across this significant

transition (Reddy and Evans 2009). Although some global events show uniform

evolutionary history among the ancient crustal blocks of the world, each Archean cratonic

block followed unique path during its evolution across Archean-Proterozoic boundary

(Eriksson et al., 2011). Based on the available geochronological data, a compilation of the

major geodynamic processes that were responsible for the crustal evolution of the

Singhbhum cratonic province is summarized in chronostratigraphic framework in Table

2.10.


P a g e | 6 7

Event Age and data source Geochronological method

Youngest Thermal events (800-900 Ma) 803±116 to 966±32 Ma : Mookerjee (2000) Rb-Sr WR age (emplacement of Ekma, Itma and

Timna Granite; culmination of

Gangpur Orogeny related to Satpura Orogeny ?)

Thermal events (1200-1000Ma) 1080 to 1290 Ma: Sarkar et al. (1969); Sarkar & Saha (1977) K-Ar WR age (third phase of Newer Dolerite dyke,

Reactivation of SSZ, Metamorphism

of mobile belts )

Thermal events (1500–1400 Ma) 1487±34 Ma: Sengupta et al. (2000) Rb–Sr age

(Second phase of Newer Dolerite Dyke) 1547±20 Ma: Saha (1994) K–Ar age

Crystallization of Chandil 1628.5±4.3 Ma: Reddy et al. (2009) U–Pb SHRIMP concordant age

Rhyolite and c. 1600 Ma 1619±38 Ma: Roy et al. (2002b) Rb–SrWR Events (reactivation of SSZ, c. 1580 Ma: Krishna Rao et al. (1979) Pb/Pb age

Emplacement of Kuilapal Granite, 1677±11 Ma: Sarkar et al. (1986) Rb–Sr, Pb/Pb ages

Mafic intrusives north of Dalma) 1638±38 Ma: Sengupta et al. (1994) Rb–Sr age

Thermal events (2100–2000 Ma) 2072±106 Ma: Roy et al. (2002a, b) Sm–Nd age

(first phase of Newer Dolerite Dykes) c. 2008 Ma: Iyenger et al. (1981) Rb–Sr age c. 1960 Ma: Vohra et al. (1991) Rb–Sr age

Thermal events (c. 2200 Ma) 2250±81 Ma: Misra & Johnson (2005) 207Pb/206Pb age

(Jagannathpur Lava, Possibly Malangtoli lava; emplacement

of Soda granite etc along re-

activated SSZ)

Thermal events c. 2800 Ma c. 2800 Ma: Bandyopadhyay et al.(2001) 207Pb/206Pb age (emplacement of Temperkola c. 2800 Ma: Acharyya et al.(2010a, b) U–Pb zircon age

Granite; emplacement of the 2858±17 Ma : Misra & Johnson (2005) 207Pb/206Pb age

main phase of Mayurbhanj Granite, Dhanjori Volcanics)

Metamorphic event 3241±7 Ma: Mishra et al. (1999) 207Pb/206Pb age Emplacement of Singhbhum 3288±8 Ma: Reddy et al. (2009) U–Pb SHRIMP

concordant age Granitoid phase III

Emplacement of Singhbhum 3328±7 Ma: Mishra et al. (1999) 207Pb/206Pb age

Granitoid phase II concordant age 3290±8.6 Ma: Tait et al. (2010) U–Pb SHRIMP

Thermal Pb-loss event c. 3350 Ma: Basu et al. (1996) U–Pb age

Emplacement of OMTG–IOG 3437±9 Ma: Mishra et al. (1999) 207Pb/206Pb age

Sedimentation age 3448±19 Ma: Basu et al. (2008), Acharyya et al. (2010a, b) U–Pb zircon

OMG sedimentation age 3500 Ma: Mishra et al. 1999 207Pb/206Pb age

Southern IOG 3506.8±2.3 Ma: Mukhopadhyay et al. (2008) U–Pb age (oldest Indian greenstone succession) SHRIMP age

Crust formation including 3.35 and 3.33 Ga (Hofmann and Mazumder, 2015) U-Pb zircon

significant granitoid component c. 3600 Ma: Mishra et al. (1999) 207Pb/206Pb age

(detrital OMG zircons) ~3.55 Ga (Goswami et al., 1995)

Table 2.10. The compilation of some recent and available geochronological data showing major

geodynamic events that took place during the crustal evolution of Singhbhum Craton (modified

after Mazumder et al., 2012).

Table 2.11. The compilation of some recent and available geochronological data showing major

geodynamic events that took place during the crustal evolution of Singhbhum Craton (modified

after Mazumder et al., 2012).


P a g e | 6 8

Fig. 2.20. Geological Map of Singhbhum craton showing the distribution of unclassified siliciclastic rocks (deep yellow in colour) in southern and western

part of the craton (map modified and redrawn after, Saha, 1992). Red dots are the locations of radioactive conglomerate occurrences.

Fig. 2.23. Geological Map of Singhbhum craton showing the distribution of unclassified siliciclastic rocks (yellow in colour) in southern and western part

of the craton (map modified and redrawn after, Saha, 1992). Red dots are the locations of radioactive conglomerate occurrences.

chapter 2 review on the precambrian stratigraphy of the ...€¦ · important for understanding...

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