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Acknowledgement

I would like to acknowledge and express my gratitude to Dr. Aashima

Sakia and Mr. R.P.Singh for guiding us throughout the trip .Special

mention must be given to teachers at Kumaun University who took out

time from their schedule and gave us a firsthand knowledge of geology of

areas,in and around Nainital .

I am grateful to my entire team members and classmates for their kind

co-operation and help in the field.

COMMON TERMINOLOGIES USED IN THE FIELD

STRIKE: - The direction of a line formed by the intersection of bedding

and a horizontal plane.

DIP: - It is the angle that it makes with a horizontal plane in a direction

perpendicular to the strike of the plane.

FAULT: - It is the plane along which the relative displacement of beds is

taking place.

JOINT: - Joints are opening or cracks in the rocks that join the simplest

fracture structure without involving displacement of the surface.

CLEAVAGE: - It is the formation of a set of fractures along closely

spaced, parallel surface in a rock by the alignment of various

mineralogical and structural elements during metamorphism and

deformation.

RIPPLE MARKS: - is another common sedimentary structure which is

frequently used to determine facing. Ripple marks may form on the

bottom of the water or by wind action at the surface of the Earth.

SYN-FORM: A fold that closes downward.

ANTI-FORM: A fold that closes upward.

CROSS BEDDING: - Cross bedding is a type of stratification in which

some sediment layers have an inclined attitude in relation to those

immediately above or below.

SLICKENSIDE:A lineation on a fault or bedding plane caused by the

frictional movement of rock body against another. The plane may be

coated by mineral often Quartz or Calcite, which itself shows striations in

the direction of movement.

Field Equipments & Procedures

BRUNTON COMPASS: - Designed by Canadian scientist/geologist

D.W. Brunton, it is used for field mapping of geological objects by

Geologists. It provides a precise sighting clinometers and hand level

capacity.

HAMMER: - A heavy hard steel geological hammer with one side blunt,

to crush and hence break the rock along fractures and partings. It should

preferable have a rubber grip.

HAND LENS:- A hard lens is used to magnify the textural feature of the

rock sample when held closely between the eye and the sample towards

the sources of light.

SATCHEL: - A cloth bag for carrying rock samples and field equipments,

with special pockets provided.

FIELD DIARY: - It is used to note down the data and observation,

including sketches observed or collected from the field.

MEASURING STRIKE:-Place the bottom edge of the brunton compass at

against the plane of intersect.Adjust the compass orientation, making

sure the bottom edge is always flat against the plane, until the air bubble

in the Bull is Eye level’ is centered.Read either end of the compass

needle to obtain the value of strike.

MEASURING DIP:-

After determining the strike, we rotate the compass 90.Place the side of

the compass flat against the plane.Adjust lever on the back of the

compass until the air bubble in the ‘clinometers level’ is centered.Read

the dip directly from the scale in the compass.

REGIONAL GEOLOGICAL SETTING

The Nainital hills represent the southeastern part of a strip of enechelon

basins of the Krol belt, which stretches southeastward from Solan

(Himachal) to Nainital (Uttarakhand).The southern limit of the Krol belt is

delineated by the highly tectonized rocks of the Amritpur granites which

have been brought up along Main Boundary Thrust (MBT).

The sedimentary succession of Krol belt in Nainital area begins with the Nagthat Formation of the Jaunsar Group, which is sharply overlain by the Blaini Formation, which in turn gives way to Krol and Tal formations. These outer Lesser Himalayan rocks are sandwiched between the Main Boundary Thrust (MBT) in the south, which separates them from the Neogene Siwalik and Ramgarh thrust in the north marking a faulted contact with crystallines rocks of the Almora Nappe. The rocks aredipping north to northeast at angles ranging 10° to 60°.

The Almora hills represent the central sector of the Almora Nappe,

stretching west from Dandeldhura (western Nepal) to Dudhatoli in

Garhwal, Geologists have recognized the Almora Nappe a thick pile of

metasedimentaries and granites, representing central crystallines

designated as Saryu Formation,Gwalikhet Formation and Champawat

granitoid as the Almora Group, and the lower Nathuwakhan Formation

and Ramgarh (Devguru) Porphyry as Ramgarh Group.

NAINITAL:

The lake district of the mountains,Nainital town was first discovered by an

English traveller P. Barren in 1842. The town witnessed a devastating

landslide in September 1880, which also created today’s playground, or

Flats on the northwestern corner of the lake. Set over 2000m above the

sea, the headquarter of Nainital rises around its large lake. Being a

touristic place, it is highly crowed during summer months of April to June.

DAY ONE(17.12.11)

LOCATION: Durham House near Sherwood College OBJECTIVES: To observe the rocks of the Upper Krol and their Biohermal structures. A thick succession of light to dark-grey dolomite of upper Krol succession characterizing development of 1000 to 900 m.y. old biohermal structures is well exposed at this site. The important bioherm (stromatolites) present in this rock unit are columnar, laminar, domal, oncoidal, plumose and irregular stromatolites. The bioherms are namely Baicalia baicalica, Kursinella, Minjaria, Colonella Columnaris . These bioherms suggest a shallow marine depositional environment in middle to late Proterozoic age.

1000 to 900 m.y. old biohermal structures (stromatolites) built by algae-bacteria are exposed in Sherwood College section

Elephant skin texture dolomite

Highly weathered

Taking out dip strike at durham

house.

2119m

N29.22.54

E79.27.24

Strike=N50E

Dip=56SE

Some shales & slate also seen

DAY TWO(18.12.11) LOCATION : Naina Devi OBJECTIVES: To observe the rocks of the Upper Krol

LOCATION: Bada patthar,Tiffin Top, OBJECTIVES: To observe phyllites

Intensely folded slates & shales

and some phyllites.

1936m

N29.23.16

E79.27.18

Strike=N62W

Dip=52NW

Striated rocks due to tectonic

activity

LOCATION :Lands End OBJECTIVE: To observe the rocks of Upper Krol - Tal succession, and P-c Boundary The lower part of the sequence characterizes interbeds of pyretic, carbonaceous shales and dolomite; however the upper part has grey and purple shales with local, isolated beds of fine to medium-grained sandstone. In the upper levels (Gairkhet Member), the Tal Formation becomes sandy with thick (1-3m thick) horizons of sandstone, silty shales and dolomite.

Flame structures

as seen on the

rock

Interbedding of pyritic

shale & dolomite

N29.22’48.3”

E79.26’10”

2027m

LOCATION: Narayan Nagar OBJECTIVES: To observe the rocks of Upper Krol - Tal succession, and

A thick succession of grey-black coloured, carbonaceous silty shales and dolomites marking the transition between the Krol and the Tal Formations. Corresponding sedimentary log

Succession of grey-black carbonaceous silty shales and dolomites marking the transition between the Krol and the Tal formations at

charkhet.

N29.23;6”

E79.25’50”

1849m

Strike=N10

Dip=21SE

This horizon marks the Precambrian-Cambrian boundary within the Lesser

Himalaya.

DAY THREE(19.12.11)

LOCATION: Pines Nala and OBJECTIVES: To observe Early- Proterozoic rocks of the Blaini Formation(Mussourie group) A thick succession (~1200m) of Blaini Formation is characterized by interbedded diamictite and quartzarenite sequence with subordinate representation of limestone,siltstone and shale horizons

Diamictite

1892m

N29.23’23”-

E79.28’40”

The diamictite units have sharp contacts with the quartz

arenites, and are mostly

matrix-supported

other secondary

structures visible are

hummocky

ripple,lamination etc

Plume structure

LOCATION: Bhowali (Cant) OBJECTIVES: To observe the rocks of Lower Krol Rocks of Lower Krol (Krol- A) are greenish grey gypsaceous silty shales characterizing fining upward cycles. The sequence shows small-scale parallel laminations, micro ripples, ripples cross-laminations and faintly developed large scale cross-beds. The bed transitions are sharp and sometimes even erosional.

strike=N203

dip=26SE

purple phyllite overlaying

diamictite overlaying

grey-green gypsaceous

silty shales

LOCATION: Bhimtal OBJECTICES: To observe Paleo-Proterozoic Bhimtal Volcanic suit The Palaeo-Proterozoic volcanism has been found in abundance in the region of the Kumaun Himalaya that led the stretching and partings of the floor of the Lesser Himalayan Sea. The Bhimtal Volcanics are vesicular, amygdaloidal, cut by dolerite dykes and sills and are associated with spilitic lavas.

N29.20’15”

E79.33’36”

1342m

Strike=N25

Dip=35SE

Highly weathered

basalt(greenish

hornblende basalt)

LOCATION: Amritpur OBJECTIVES: To observe ~1800my old Amritpur granite & deformation along MBT The Amritpur granites is Pre Himalayan, Precambrian granite of porphyritic and equigranular nature. The mineralogical and geochemical characteristics are consistent with those of S-type granites; however the melt produced by anatexis has intruded into the Precambrian Bhimtal-Bhowali litho succession.

942m

N29.18’37”

E79.33’26”

Thin section was made of

samples taken from here

Gorge section enroute Amritpur

Various coloured granite

samples were seen (purple to

leucocratic)

Dyke intrusion assumed due to

change in colours &

lithology.LEFT.

Gola river section near Amritpur is the most critical section that exposes a ~100m thick deformation zone, namely the MBT Zone. This zone consists several subzones each showing a characteristic style of deformation. This section clearly shows that the leucratic component of Amritpur granite overlies a well foliated and intensely kinked metabasalt green schist.

The section showing different deformation zones in Main Boundary Thrust

DAY FOUR(20.12.11)

LOCATION: Niglat (Bhowali Gaon)(10 KM stone) OBJECTIVES: To observe the Lowe-Proterozoic rocks of the Nagthat Formation The Nagthat Formation, made up of a thick succession (~1400m) of quartzarenite associated with penecontemporaneous lava flows, constitutes the lowest siliciclastic litho unit of the Krol-Belt. The basaltic flows are interbedded with the quartzarenite horizons. It is overlain by the Blaini Formation with a distinct sharp contact. The quartzarenites sequence of the Nagthat Formation comprising fine to coarse-grained quartzarenite interbedded with siltstone and grey to pink silty shales, shows coarsening upwards.

Very hard basalt

found pene-

contemporaeous

with Krol.

Blini & Krol Fm

contact seen

Lava & quartz

arenite seen

LOCATION:ENROUTE RATI GHAT

Pyrite leaching also seen

trough the rocks.

(golden in colour)

All types of tectonic folds

seen in road cut section

Folding,chevron folding

etc

LOCATION: Ratighat OBJECTIVES: To observe the Garampani Fault The Lesser Himalayan tear faults and fractures are oriented predominantly in the NW/NNW –SE/SSE directions, along them the streams and rivers have carved wide and straight valleys. The most important fault is the one which follows the north – south courses of the Garampani fault, established as a tear fault, follows the north-south courses of the Khairna and Kuch Gad streams, and is traceable through Ratighat and Garampani to Bamsyu on Bhowali – Ranikhet road section. Offsetting of Ramgarh lithounit by 700m, faulted quartz veins, fault breccia, slickensides, striations, faulting of fluvial terraces suggest a brittle nature of the Garampani fault.

CLOCKWISE presence of fault breccias suggests brittle nature of the fault, and mylonitized rocks relative movement of walls along the fault has produces slickensides with high angle & The trace of this fault is characterizes by fault scarp, cone and facets and straight sediment filled valley.

LOCATION: Lohai- Bhujan OBJECTIVES: To observe the Ramgarh Thrust and mylonitized Ramgarh Porphyry An assemblage of low-grade metamorphics, comprising of porphyritic granite, metaflysch, carbonaceous phyllites and marble, thrust over the Nagthat quartzites has been recognized as the Ramgarh Nappe. The marginal parts of these granitic rocks are mylonitic to ultramylonite/pseudo trachyte and finegrained streaky banded mylonites found in a wide zone.

Mylonitic to ultramylonite and fine- grained streaky banded mylonite.

Quart z vein intrusions in rocks of Ramgarh.& quartz Vein in 2D

Micro hydro electric project,Ramgarh

LOCATION :Kakrighat OBJECTIVE:to view Garnet Mica schist At Kakrighat quartz-mica-schist (garnetiferous) of the Saryu Formation of Almora Group are thrust over fine grained sericitic quartzites and metasiltstone of the Nathuwakhan Formation of Ramgarh Group along the South Almora Thrust (SAT). Increase in grade of metamorphism and deformation has been observed from base (green schist facies) to top (amphibolite facies) across the SAT.

Garnet mica schist from

Kakrighat.

LAB WORK

THE THIN SECTION AND SEM-EDS WERE MADE OF THE FOLLOWING:

Basalt

Trachytic texture

Granite

Garnet mica Schist

HORNEBLEND BASALT FROM

BHIMTAL

MINERALS PRESENT: p-clase,

Quartz,Hornblende,pyroxene

Amritpur granite

Minerals present:

quartz,plagioclase,

biotite, muscovite

GMS from kakrighat

Augen structure, mica fish, garnet,

biotite, quartz, muscovite

Scanning Electron Microscope

granite

Spectrum processing :

Peak possibly omitted : 2.142 keV

Processing option : Oxygen by stoichiometry (Normalised)

Number of iterations = 2

Element Weight% Atomic% Compd% Formula

Na K 1.26 1.15 1.69 Na2O

Mg K 0.51 0.44 0.85 MgO

Al K 11.41 8.87 21.55 Al2O3

Si K 30.30 22.63 64.81 SiO2

K K 5.11 2.74 6.16 K2O

Ti K 1.02 0.45 1.71 TiO2

Fe K 2.51 0.94 3.22 FeO

O 47.88 62.78

Totals 100.00

Garnet Mica Schist

Spectrum processing :

Peaks possibly omitted : 2.140, 9.720 keV

Processing option : Oxygen by stoichiometry (Normalised)

Number of iterations = 2

Element Weight% Atomic% Compd% Formula

Na K 2.17 1.96 2.92 Na2O

Al K 9.68 7.46 18.29 Al2O3

Si K 32.73 24.23 70.02 SiO2

K K 4.16 2.21 5.01 K2O

Ti K 0.67 0.29 1.13 TiO2

Fe K 2.04 0.76 2.63 FeO

O 48.54 63.08

Totals 100.00

GARNET MICA SCHIST

Spectrum processing :

Peaks possibly omitted : 2.143, 4.450 keV

Processing option : Oxygen by stoichiometry (Normalised)

Number of iterations = 3

Element Weight% Atomic% Compd% Formula

Na K 0.81 0.75 1.09 Na2O

Mg K 1.87 1.65 3.10 MgO

Al K 9.23 7.32 17.43 Al2O3

Si K 29.03 22.14 62.11 SiO2

K K 9.73 5.33 11.72 K2O

Ca K 0.61 0.32 0.85 CaO

Fe K 2.87 1.10 3.69 FeO

O 45.85 61.38

Totals 100.00

Basalt

Comment:bhimtal basalt

Conclusion

Our second field trip to Uttrakhand (Nainital) was a success and an

enthralling experience in all ways. It enhanced our knowledge about

various aspects of geology from structural to stratigraphy.

We were made familiar with geology of Uttrakhand in general&

Nainital in particular. We also got to know about the various textural

varieties of rock and their identification. We have observed various

kinds of folds and different kinds of intrusion. We learnt various

aspects of sedimentational environment through ripples and cross-

bedding.

We are thankful to our department for providing this opportunity to

us. We are also thankful to our professors for their guidance during

this field.

Bibliography

• Field guide by P.D. Pant