bachelor thesis · 2018. 6. 8. · degree project in geology 15 hp bachelor thesis stockholm 2016...

Degree Project in Geology 15 hp

Bachelor Thesis

Stockholm 2016

Department of Geological SciencesStockholm UniversitySE-106 91 Stockholm

Sweden

Mineralogical characterisation of REE-bearing mineralisations in Knutsbo, Bergslagen

Karolina Mattsson

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Mineralogical characterisation of REE-bearing mineralisations in

Knutsbo, Bergslagen.

Karolina Mattsson

Abstract With a growing interest for rare earth elements (REE) and its industry, the EU has financed a project

called EUrare, regarding REE deposits in Europe with aim to safeguard and create a sustainable REE

industry. The Geological Survey of Sweden (SGU) has in relation to this project studied the so called

REE-line, located in west-central Bergslagen, along with other locations. Knutsbo lies at the northern

end of this extensive lens of 80 km of supracrustal rocks, with a bedrock of mainly granitoid-dioritoid-

gabbroid (GDG) mafic intrusive rocks. Previous studies and excursions have proved possibilities for

REE-bearing mineralisations in the area, which led to an undergraduate thesis with aim to further

investigate this cause. Through mineral observations in thin section collected from the area and SEM

analyses, the area proved to have mineralisations of mainly allanite, tremolite, quartz and actinolite.

A reoccurring mineral observed with pale brown-coloured pleochroism and high relief was of special

interest for analysis and proved to be REE-bearing. The REEs encountered in the samples were mainly

lanthanum (La) and cerium (Ce), with some traces of for instance yttrium (Y) which are more

uncertain. REE-bearing mineralisations are believed to be allanite, dollaseite törnebohmite and

västmanlandite. The analyses proves presence of REEs in the area and the results in this report will

hopefully encourage further studies regarding the subject.

Keywords: geology, rare earth elements, REE, mineralisations, ore deposits, volcanite, granites,

Fennoscandian Shield, Bergslagen, Knutsbo.

Supervisors: Joakim Mansfeld (Institution of Geology, Stockholm) and Magnus Ripa (SGU)

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Mineralogisk karaktärisering av sällsynta jordartsmetaller i

mineraliseringar i Knutsbo, Bergslagen.

Karolina Mattsson

AbstraktI samband med ett ökat intresse för sällsynta jordartsmetaller (REE) och dess industri har EU

finansierat ett projekt kallat EUrare, med syfte att skapa en säker och hållbar industri för sällsynta

jordartsmetaller i Europa. Sveriges Geologiska Undersökning (SGU) har i samband med detta projekt

studerat den så kallade REE-linjen i västcentrala Bergslagen, tillsammans med andra platser. Knutsbo

ligger på den norra änden av denna omfattande lins av 80 km ytbergarter, med en berggrund

bestående av huvudsakligen granitoid-dioritoid-gabbroid (GDG) mafisk, intrusiv berggrund. Tidigare

studier och exkursioner har bevisat möjliga REE-bärande mineraliseringar i området, vilket har lett till

möjligheten för ett examensarbete med syfte att studera detta område mer i detalj. Genom att

observera mineral i tunnslip från området och genomföra SEM-analys har området visat sig

framförallt innehålla mineral av allanit, tremolit, kvarts och aktinolit. Ett återkommande mineral med

svag brun pleochroism och hög relief observerades i proverna och var av speciellt intresse för analys,

som senare visade sig vara REE-bärande. De sällsynta jordartsmetallerna som upptäcktes i proverna

var framförallt lantan (La) och cerium (Ce), men även spår av yttrium (Y) som är mer osäkra. REE-

bärande mineraliseringar tros vara allanit, dollaseit, törnebohmit och västmanlandit. Analyserna

bevisar fyndigheter av sällsynta jordartsmetaller i området och resultaten i denna rapport

uppmuntrar förhoppningsvis vidare studier inom ämnet.

Nyckelord: geologi, sällsynta jordartsmetaller, REE, mineralisering, malmfyndigheter, vulkanit, granit,

Fennoskandiska skölden, Bergslagen, Knutsbo.

Handledare: Joakim Mansfeld (Geologiska institutionen, Stockholm) och Magnus Ripa (SGU).

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Table of Contents 1. Introduction ......................................................................................................................................... 2

1.1 Aims ............................................................................................................................................... 2

2. Background .......................................................................................................................................... 2

2.1 Regional geology ........................................................................................................................... 2

2.1.1 Fennoscandian Shield ............................................................................................................. 2

2.1.2 Bergslagen .............................................................................................................................. 4

2.2 Local geology ................................................................................................................................. 5

2.2.1 Knutsbo ................................................................................................................................... 5

3. Methods .............................................................................................................................................. 6

3.1 Field trip ......................................................................................................................................... 6

3.2 Rock samples ................................................................................................................................. 6

3.3 Thin sections studies ..................................................................................................................... 7

3.4 SEM analysis .................................................................................................................................. 7

3.5 Calculations of data ....................................................................................................................... 7

4. Results ................................................................................................................................................. 7

4.1 Mineralogy..................................................................................................................................... 7

4.1.1 Gruvhagen .............................................................................................................................. 7

4.1.2 Mörkens .................................................................................................................................. 8

4.1.3 Knutsbo ................................................................................................................................... 9

4.2 SEM analysis .................................................................................................................................. 9

5. Discussion .......................................................................................................................................... 10

5.1 Mineralogy................................................................................................................................... 10

5.2 SEM results .................................................................................................................................. 18

5.3 Local geology ............................................................................................................................... 19

6. Conclusions ........................................................................................................................................ 19

7. Acknowledgements ........................................................................................................................... 19

References ............................................................................................................................................. 20

Appendix ................................................................................................................................................ 21

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1. Introduction The bedrock of Sweden has gone through

several processes to eventually form the

geology present today. The composition and

age of the rocks differ from north to south but

are all part of the Fennoscandian Shield that

started to form around three billion years ago

(Andersson, 2004). As a result of the

geological processes that have occurred

during the formation of the Fennoscandian

shield in parts of Sweden, different rock types

have locally developed along with ore deposits

of various kinds. These deposits have been

explored and mined over a long period of time

and include important ore deposits like base

metal sulphide and iron oxide (e.g., SGA

Excursion Guidebook, 2013)

The area of Bergslagen in central Sweden has

been one of the regions where mining and

exploitation of mineral deposits have been of

great importance. The area is mainly rich in

iron oxides and base metals but also include

deposits of rare earth elements (REE) in west-

central Bergslagen (fig. 1). Because of this,

Sweden is included in the EURare project,

financed by the EU to set a basis for the

development of a European rare earth

element industry. The sectors of EU economy

deem it important to safeguard the supply of

REE materials and products to create a

sustainable, economically viable and

environmentally friendly industry of REEs in

Europe.

The exploration of REEs is done through

mapping in regions of interest, where the

Geological Survey of Sweden (SGU) has further

studied, among other areas, the REE-line in

Bergslagen (fig. 1). Through these previous

studies and collected samples, the Knutsbo

area have come of interest for REE deposits

that are to be further examined. In this report

its potential is reviewed in terms of samples

collected by the SGU.

1.1 Aims This report is an undergraduate (15 hp) thesis

in collaboration with the SGU and a part of the

EU-financed EURare project regarding REE

deposits in Sweden. The thesis aims to

investigate possible REE occurrences in the

Knutsbo area through already collected

samples (by SGU). Along with rock samples,

and analyses of thin sections and previously

gathered information from the SGU during

excursions and studies, the area of Knutsbo

have been described geologically and possible

REE-bearing mineralisations have been

identified. The framing of questions that are

examined and discussed in this report can be

summarised to the following bullet points:

Geologically describe the region of

Knutsbo.

Determine possible REE occurrences

in collected samples.

If present, what are the hosting

mineral(s) of the REEs?

2. Background

2.1 Regional geology 2.1.1 Fennoscandian Shield The following description is largely based on

the SGA Excursion Guidebook (2013). The

Fennoscandian Shield is one of planet Earth’s

ancient continental nuclei. It consists of a

collage of an Archean craton in the north-east

and towards the present day south-west

accreted magmatic domains. The major part is

composed of the Palaeoproterozoic

Svecokarelian orogeny (Stephens et al. 2009).

Large parts of the Shield are overlain by

platformal rocks which formed as sedimentary

basinal material in the south-east. The

magmatic domains amalgamated

progressively over time for more than one

billion years.

Juvenile crust was formed at 2.1-1.9 Ga in

numerous arc systems around the Archean

craton in the south-west which lead to

‘microcontinents’ in some regions, such as the

Bergslagen area (Andersson, 2004). The early

Svecokarelian rock-forming phase at 1.9-1.86

Ga resulted in thorough reworking, partly

including rift-related volcanism, of the earlier

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Fig. 1. Geological map of the Bergslagen area (modified from Kampmann, 2015). The approximate extent of the REE line and position of Knutsbo are indicated.

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arc systems in addition to the major formation

of newly formed juvenile crust between

microcontinents. Once accretion was

completed, subsequent east- and northward

subduction lead to reworking of the newly

formed crust during the late Svecokarelian

orogeny (1.85-1.75 Ga). In Bergslagen, this

resulted in granitoid magmatism and regional

metamorphism in the area (Andersson, 2004).

The Svecokarelian orogen hosts the largest

orogenic system. The bedrock was affected by

ductile deformation, metamorphism and

associated magmatic activity around 2.0-1.8

Ga, and started to react to crustal

deformation in a brittle manner around 1.8-

1.7 Ga. In addition to the Svecokarelian

orogeny, the part of the Fennoscandian Shield

located in Sweden is mainly composed of two

younger and spatially distinct orogens; the

Blekinge-Bornholm and Sveconorwegian

orogenies.

The orogenic processes locally lead to the

formation of an abundance of mineral

resources, and several ore districts in the

Fennoscandian Shield, where in particular the

Palaeoproterozoic assemblages are hosts to

many major mineral deposits of various types

(SGA Excursion Guidebook, 2013). All currently

active operating mines in Sweden are located

within the 2.0-1.8 Ga accretionary

Svecokarelian orogen (SGA Excursion

Guidebook, 2013).

Sweden has had an extensive mining and

mineral prospecting industry for centuries

where the most important types of ore

deposits include: volcanogenic massive

sulphide deposits; volcanic- and carbonate- or

skarn-hosted, replacement-type Zn-Pb-Ag-(Cu-

Au) sulphide and Fe oxide deposits, Cu-Au

deposits hosted by intrusive rock; and

orogenic gold deposits (SGA Excursion

Guidebook, 2013). Along with these well-

documented deposits, new types of deposits

are being explored, including Fe oxide-Cu-Au

deposits and REE, Li, Te deposits (SGA

Excursion Guidebook, 2013). No major or

economic mineral deposit has been found in

the Archean rocks in Sweden.

There are occurrences of other metals within

the borders of Sweden, including REE, Li, Mo,

Sn, W and U. In later years, a global interest

for rare earth element (REE) mineralisations

has surfaced which has ensued in rather

intense exploration for these metals also in

Sweden (SGA Excursion Guidebook, 2013).

Evidence of REE-bearing minerals have for

instance been found at numerous places in

Bergslagen, forming a line following an ore

belt hereby known as the “REE-line” (fig. 1).

2.1.2 Bergslagen The region of Bergslagen is located in the

south-western part of the Svecokarelian

orogen in the Fennoscandian Shield (fig. 1).

The rocks are of Palaeoproterozoic origin and

were formed and metamorphosed between

1.9 and 1.8 Ga. The rocks of the westernmost

part of the area were also affected by

deformation and metamorphism by a

Sveconorwegian tectonic overprint between

1.0 and 0.9 Ga (Stephens et al. 2009).The

region is rich in metallic mineral deposits with

three currently operating mines at base metal

sulphide deposits. These metallic mineral

deposits of Bergslagen can be found in the

hosting metamorphosed and hydrothermally

altered felsic volcanic rock and associated

skarn or crystalline carbonate rock (Stephens

et al. 2009).

Geijer & Magnusson (1944) mentioned two

types of rock that make up the bedrock of

Bergslagen; the supra-crustal so-called leptite

formation and contemporaneous and younger

granites. Mafic rocks and amphibolites occur

subordinately. In modern descriptions of

Bergslagen geology, the leptite formation

corresponds to Svecofennian felsic

metavolcanic rocks and the younger granite

correspond to granite-dioritoid-gabbroid

(GDG), granite-pegmatite (GP) and granite-

syenitoid-dioritoid-gabbroid (GSDG) intrusive

rock suites (Stephens et al. 2009). The volcanic

rocks were in places transformed into gneisses

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due to Svecokarelian metamorphism, but in

general they were only affected by

amphibolite, locally even greenschist, facies

conditions. The similarity in chemical

character between the older granites and

volcanic rocks indicates some sort of common

lineage according to Geijer & Magnusson

(1944).

Virtually all iron and sulphide ore deposits in

the Bergslagen region are found in, and were

largely formed at the same time or slightly

later than the supracrustal rocks (Geijer &

Magnusson 1944; Stephens et al. 2009). Iron

dominates the oxide deposits in the

Bergslagen region. They contain various

amounts of manganese in associated skarn

and crystalline carbonate rocks. There is also a

presence of iron sulphides and base metal

sulphides as well as rarities like uranium,

tungsten and rare earth elements (REE).

Manganese-poor skarn or crystalline

carbonate rock hosting iron oxide deposits are

the most common type of iron oxide

mineralisation in the region (Stephens et al.

2009).

The iron deposits in Bergslagen can be divided

into the following types: quartz-banded (BIF)

ores, skarn and lime ores and apatite-bearing

ores. Geijer & Magnusson (1944) interpreted

the banded iron formation as a product of

chemical sedimentation, where the material

probably surfaced onto the palaeoseafloor

through hot springs or similar forms of

emanations from the same magma masses

that fed surface eruptions. The skarn and lime

ores are formed from variably altered and

metamorphosed limestone.

The Bergslagen ore district contains several

thousands of Fe oxides and polymetallic base

metal sulphide deposits. There are three

deposits that are currently being mined in this

district: a Zn-Pb-Ag-(Cu-Au) sulphide deposits

at Garpenberg, a Zn-Pb-Ag sulphide deposit in

Zinkgruvan with subordinate Cu, and a Zn-Pb-

Ag sulphide at Lovisagruvan (SGA Excursion

Guidebook, 2013).

Bastnäs, located in the central of the REE-line

in Bergslagen, is one of best known REE-

bearing occurrences in Bergslagen. The

dominant country rock is an altered and

metamorphosed volcanic rock. The

surrounding area hosts numerous iron oxide

and base metal sulphide deposits (Andersson,

2004). The REE occurrences can be divided

into two subtypes according to Holtstam et al.

(2014): those enriched in light REEs (LREEs)

and Fe, and those enriched in heavy REEs

(HREEs), Y, Mg, Ca and F. The deposits in

Bastnäs are considered rich in LREE while the

district of Norberg further north is richer in

HREEs. Ferriallanite-(Ce), also known as

“cerine” or iron-rich “allanite”, and cerite-(Ce)

are the most common lanthanide mineral in

Bastnäs (Holtstam et al. 2003).

2.2 Local geology

2.2.1 Knutsbo Knutsbo is located just at the northern end of

the extensive lens of 80 km of supracrustal

rocks, known as the Nora-Riddarhyttan-

Norberg area, together forming the “REE-line”

(fig. 1). Intrusive rocks surround this region to

the east and intrusive and supracrustal rocks

in the west (Andersson, 2004).

As shown in figure 2, the bedrock at Knutsbo

consists of granitoid-dioritoid-gabbroid (GDG)

mafic intrusive rocks with GDG-type granite

and granodiorite to the south and GDG-type

granodiorite in the west. The mineralisations

at Knutsbo which host the REE-bearing

minerals, in turn, presumably occur as

supracrustal xenoliths in the GDG-rocks

(Persson, 1997)

Just like in the majority of Bergslagen rocks,

have the rocks around Knutsbo been affected

by amphibolite facies metamorphism.

Geophysical and topographic data indicate

several lineaments in the area, which could be

possible faults. The mineral lineations plunge

around 40 degrees north-east while tectonic

foliation strike around 290 degrees and dips

40 to 70 degrees north to north-northwest.

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There are occurrences of quartz rich iron oxide

deposits in the area, including banded iron

formation (BIF).

3. Methods

3.1 Field trip

A fieldtrip guided by Per Nysten and Magnus

Ripa from SGU to the area of Knutsbo was

conducted during the 14th of April, where the

aim was to get a further understanding for the

region regarding rock types and other

geological features of importance for the

project. Four pits in the Knutsbo area were

visited where the samples previously collected

by the SGU had been taken. Strike and dip

were measured in areas displaying foliation

patterns (fig. 3) and a few new rock samples

were collected for further studies.

During the 21st and 22nd of April, a second

fieldtrip guided by Magnus Ripa (SGU) and

accompanied by Joakim Mansfeld (Stockholm

University) to the REE-line was conducted. The

aim was to get an overlook of the so called

REE-line in perspective of geology and

mineralogy. Previously mapped areas by the

SGU were visited. The outcrops displayed

certain foliations or other geological features

of interest. Places like Bastnäs were visited,

where evidence of mining is clearly shown. In

addition, Stora Malmkärra, Plåtängsgruvan,

Bojmossfältet and Östanmossa were visited.

3.2 Rock samples As mentioned in the introduction, a number of

rock samples collected by the SGU during a

national inventory of possible REE occurrences

in Sweden (the EU-financed EURare project).

Some of these samples were taken at Knutsbo

since this deposit was mentioned as

Fig. 2. Extract from the bedrock map of the Geological Survey of Sweden (Persson 1997). Green colour denotes GDG-type mafic intrusive rocks, brown colour denotes GDG-type granite to granodiorite, brown colour with green dots denotes GDG-type granodiorite. Brown colour with red dots denotes porphyritic textures. The view is c. 3.2 km wide, north is up.

Figure 3. Foliation patterns in the Knutsbo area.

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potentially REE-bearing already by Geijer &

Magnusson (1944). Chemical analyses of the

samples revealed enrichment in particularly

light REEs (LREEs).

3.3 Thin sections studies A total of nine thin sections were produced

from samples collected by the SGU in the

Knutsbo region. These samples have been

studied in microscope, where they have been

viewed in magnifications from 2.5 to 40x. The

mineral assemblages in each sample have

been examined through parallel and crossed

polars to determine their characteristics, and

have been classified accordingly. Opaque

phases like ore minerals have been studied in

reflected light.

The nine thin sections derive from three

different areas within the Knutsbo region. Two

samples have been taken at Gruvhagen, three

samples at Mörkens and four samples at

Knutsbo. Out of these samples, four were

selected for further analysis with SEM to

detect the plausible site(s) of REEs.

3.4 SEM analysis A scanning electron microscope (SEM) was

used to determine the chemical composition

of selected minerals in the thin section

samples. A SEM is a type of electron

microscope that produces images of a sample

by scanning it with a focused beam of

electrons. The electrons interact with atoms in

the sample, producing various signals that

contain information about the surface

topography and composition of the sample.

The model used for SEM analysis was a FEI

Quanta FEG 650, where the samples were

scanned in low vacuum with a backscatter

detector. The additional software used for EDS

analysis was AZtec.

3.5 Calculations of data The results from the SEM analyses gave data

in form of weight percent (wt %). In order to

present this in an easily understandable way,

the data from each analysis were recalculated

to mineral compositions. The mole ratio was

calculated from the weight percent and

afterwards normalised according to the

amount of cations in the different minerals to

produce a more accurate result. There was

also a correction made for the sulphide, where

0.5 mole ratio of iron was removed for every

mole ratio of sulphide, giving a better end

result.

4. Results

4.1 Mineralogy

4.1.1 Gruvhagen The two thin sections from Gruvhagen are

both fibrous actinolite skarn, containing a

mineral assemblage of allanite, quartz,

actinolite and calcite. Both samples show

mainly a matrix of actinolite and quartz

crystals in ranging size (fig. 4) with some

elongated allanite crystals appearing

throughout. The remaining minerals are less

abundant and appear as minor crystals.

Both samples contain ore minerals which

show as opaque phases. Through studies in

reflected light, the samples demonstrate

presence of magnetite and hematite

throughout the thin section in minor amounts.

No sulphides are present.

No minerals in the samples from Gruvhagen

showed any significant potential for being

REE-bearing and have therefore been

excluded from SEM analysis.

Figure 4. Matrix of colourful actinolite in XPL (right) meeting with darker allanite and ore minerals (left).

8

4.1.2 Mörkens The three thin sections from Mörkens

differentiate from each other in terms of

mineral assemblages and compositions. All of

the samples show interesting characteristics

for potential REEs.

One sample from Mörkens is defined as

tremolite skarn, and contains allanite,

tremolite and quartz. Tremolite is the

abundant mineral with long and fairly large

crystals with varying sizes, while smaller

crystals of allanite and quartz occurs in a

lesser amounts. The opaque phases are ore

minerals like pyrite and some chalcopyrite.

A mineral we were unable to identify through

sheer observation occurs frequently, often

close to allanite crystals (fig. 5). It shows

similar characteristics as allanite but has

weakly brown-coloured pleochroism,

compared to allanite which has strong colours

of brown or red. Due to these observations it

is believed to have possible relations to REEs.

Another thin section sample from Mörkens is

defined as a copper-bearing quartz skarn. It

has a mineral assemblage of muscovite, quartz

and allanite. The sample consists of a mass of

quartz crystals in similar size, with muscovite

appearing throughout the sample as long

crystals in different sizes. The opaque phases

are ore minerals of chalcopyrite and possibly

iron, the latter which might occasionally

reacting to form magnetite.

The mineral allanite show similar

characteristics as in the other sample with

some weaker brown to grey pleochroistic

crystals (fig. 6). It appears abundantly in the

sample and is believed to have a relation with

REEs.

The last thin section from Mörkens in defined

as a copper-bearing amphibole skarn. It

contains minerals of amphiboles, tremolite

and quartz, along with an unknown mineral

showing the same characteristics of pale

brown pleochroism as in the previous samples

from the area. The mineral also appears as

pale brown in crossed polar, similar to the

mineral titanite and is believed to be REE-

bearing (fig. 7). The tremolite crystals are large

and abundant in the sample, their colours and

shape appearing somewhat distorted. Quartz

appear as small crystals within the matrix.

The opaque phases are mainly ore minerals of

converted pyrrhotite, shown by bird eye

Figure 7. Crystal with light to darker brown pleochroism and strong relief.

Figure 5. Mineral of pale brown pleochroism, occurring as small crystals throughout the sample.

Figure 6. Mineral appearing grey to colourless in PPL, with possible relation to REEs.

9

texture in reflected light. The sample also

contains some chalcopyrite, possibly related

to REEs.

4.1.3 Knutsbo Each of the four samples from Knutsbo differ

in mineralogy and opaque phases. One of the

samples has a matrix of quartz and biotite, the

latter often containing abundant haloes (fig.

8). Calcite is a less abundant component and

there are small occurrences of a mineral with

pale brown pleochroism, believed to be

related to REEs. The sample contains no

observed opaque phases.

Another sample from Knutsbo is defined as

quartz-banded hematite ore, seen clearly

across the thin section (fig. 9). It is abundant in

quartz along with some smaller crystals of

amphiboles like actinolite. Some possible

crystals of calcite were also observed but to a

smaller amount. The opaque phases are ore

minerals of mainly hematite, revealing some

twinning textures, along with some signs of

magnetite present in the sample.

One of the thin section samples from Knutsbo

is defined as actinolite-magnetite skarn with

pyrite. The sample has a mineral assemblage

of allanite and actinolite with large crystals of

allanite in the sample compared to the

surrounding matrix, some showing twinning

textures (fig. 10). The opaque phases are ore

minerals of pyrite along with magnetite.

Also in this sample the pale brown-coloured

pleochroistic mineral occurs, similar to that of

allanite but weaker in colour. This mineral or

the allanite itself is believed to be REE-

bearing.

The final sample from Knutsbo is defined as

quartz- and amphibole-mixed magnetite rock.

It contains minerals of quartz, amphiboles and

biotite as well as the unknown mineral

believed to be REE-bearing, appearing as pale

brown in parallel polars, much like in previous

samples. The opaque phases are ore minerals

of magnetite and hematite. No sulphides are

observed.

4.2 SEM analysis

Four thin section samples were selected for

SEM analysis, including one sample from

Knutsbo and three from Mörkens. The

minerals chosen for analysis were mainly the

crystals of lighter brown pleochroism seen in

several of the samples, as well as their closest

surroundings.

Figure 8. Biotite viewed in XPL, displaying haloes across the crystal.

Figure 10. Large crystals of what is believed to be allanite related, with brown to yellow pleochroism.

Figure 9. Quartz bands with hematite ore (opaque).

10

Through review and calculations of the SEM

results, several REEs were encountered in the

mineral assemblages in the analysed samples.

With the majority of the analyses done of the

samples from Mörkens, they reveal a variety

in REEs and their hosting mineral assemblages.

However, the mineral classifications are very

uncertain as the SEM data have been difficult

to interpret.

The samples from Mörkens revealed higher

amounts of REEs than that of Knutsbo. The

sample from Knutsbo mainly contains

tremolite-actinolite but also contains large

allanite crystals, generally poor in REEs, with

traces of for instance lanthanum (La), cerium

(Ce) and neodymium (Nd) in the allanite

crystals (tables 1 and 2).

As seen in tables 2 and 3, all three samples

from Mörkens contain dollaseite with REEs

like cerium (Ce), neodymium (Nd) and even

minor traces of praseodymium (Pr). One of

the samples from the Mörkens area contained

the mineral törnebohmite (table 4), slightly

richer in cerium (Ce) and lanthanum (La) while

another contain minerals of västmanlandite,

some being Fe-analogue and slightly richer in

iron (table 5).

Some of the more questionable results are the

presence of britholite-Y, rich in yttrium (Y) and

cerite, rich in cerium (Ce), both appearing in

the same sample (table 6). Talc was possibly

also encountered in one of the sample from

Mörkens. In addition, other possible REE-

minerals encountered in the samples could be

flourcerite, monazite, magnesiorowlandite,

and gadolinite but are all very uncertain

results and estimates (table 7).

Some of the opaque phases were also

analysed in the SEM, a majority being ore

minerals of pyrite. However, the results also

revealed presence of chalcopyrite and

pyrrhotite. The amount of REEs present in the

sulphides are low, only with some traces of

cerium (Ce) and lanthanum (La).

5. Discussion

5.1 Mineralogy The nine thin section samples previously

collected from the Knutsbo area show both

differences and similarities. They differ in their

overall appearance, the sizes of crystals, the

amount of minerals and their composition.

However, they share common mineralogy as

most of the samples contain allanite,

tremolite, quartz and actinolite. The opaque

phases in the samples are generally pyrite or

magnetite and hematite.

More importantly, almost all the samples

share an unidentifiable mineral with pale

brown pleochroism that appear as smaller

crystals in the samples. Both the samples from

Knutsbo and Mörkens show several examples

of this unknown mineral, however it seems to

be in insignificant amount or even be lacking

completely in the samples from Gruvhagen as

none more than allanite (REE-bearing) were

observed during microscopy.

As to why Gruvhagen is low on this mineral,

while Knutsbo and Mörkens have several

crystals of, is most likely a result of location as

to where the samples were collected.

Although in largely the same area, their

mineralogy and composition is slightly

different and the Gruvhagen samples may

have been collected from a generally REE-poor

location.

Since the unidentifiable mineral share

common characteristics with that of allanite,

like high relief and fairly strong, brown

pleochroism, it is believed to be related to

allanite in most of the thin sections. Although

still uncertain to say this is crystals of allanite,

since it contains a significant amount of REEs,

it can be considered to be one of REE-bearing

minerals in the samples.

As for the mineralogy itself, the observations

made are suggest metamorphism of

amphibolite facies, and possibly even

greenschist facies. With conditions of medium

11

Table 1. Recalculated data from SEM analyses of Knutsbo sample.

Weight%

Sample knut 3 knut 3 knut 3 knut 3 knut 3 knut 3

Mineral REE-poor allanite

REE-poor allanite

REE-poor allanite

REE-poor allanite

REE-poor allanite

REE-poor allanite

Analysis Spectrum 3

Spectrum 6 Spectrum 8 Spectrum 9 Spectrum 10

Spectrum 11

C 2,6 2,5 2,9 2,9 3,1 2,4

O 39,7 39,3 40,9 41,6 39,7 39,3

S 0,2

Si 16,5 17,4 17,7 17,8 17,2 17,3

Al 8,6 9,3 9,2 9,4 8,5 8,6

Fe 8,2 8 7,8 7,3 7,3 7,1

Mg 2,8 2,6 3 2,9 3,4 3,5

Ca 10 11,2 11,7 11,8 10,4 10,3

Na

K

Ti

Mn

P

Y

La 3,2 1,8 2,1 1,5 2,7 2,5

Ce 5,7 4,2 3,4 3,4 5,3 5,4

Pr 0,8 0,6

Nd 2,6 2,2 1,4 1,4 2,5 2,3

Sm 0,7 0,6

Eu

Gd

Tb

Co

Cu

Br

F

Mo

Ni

Total 100,1 100 100,1 100 100,1 99,9

12

Table 2. Recalculated data from SEM analyses of Knutsbo and Mörkens samples.

Weight%

Sample knut 3 knut 3 knut 3 knut 3 mork 3 mork 3

Mineral Allanite Allanite Allanite Allanite Dollaseite Dollaseite

Analysis Spectrum 19

Spectrum 20

Spectrum 25

Spectrum 26

Spectrum 51

Spectrum 53

C 3 1,8 3,4 3 3,1 3,2

O 36,5 37,2 37,6 36,4 36,5 35,5

S 0,3 0,2 0,6 0,5

Si 14,6 15,9 14,9 14,6 15,8 15,7

Al 7,7 9,5 9,7 8 5,6 5,6

Fe 7,3 9,1 8,6 7,6 8,4 8,3

Mg 2,5 1,3 1,5 2,2 4,8 4,9

Ca 7,4 10,4 10 7,8 5,9 5,7

Na

K

Ti

Mn

P

Y

La 4,8 3,1 2,9 4,2 3,2 3,4

Ce 10,6 6,6 6,3 9,8 9,5 9,3

Pr 1,1 0,9 0,9 1,3 1,1 1,4

Nd 4,5 3,4 3,1 4,2 5,5 5,6

Sm 0,7 0,8 0,8 0,9

Eu

Gd

Tb

Co

Cu

Br

F

Mo

Ni

Total 100 99,9 100 100,1 100 100

13

Table 3. Recalculated data from SEM analyses of Mörkens samples.

Weight%

Sample mork 3 mork1 mork1 mork 2 mork3

Mineral Dollaseite Dollaseite Dollaseite Dollaseite Dollaseite

Analysis Spectrum 50 Spectrum 71 Spectrum 76 Spectrum 83 Spectrum 36

C 3,3 5,1 5 4,6 6,2

O 34,3 34,1 34,4 33,9 32,8

S 1,1 3,8

Si 14,8 15,4 15,7 16,4 13,2

Al 5,8 3,9 3,6 3,1 5

Fe 9,5 12,8 12,4 14,7 10,5

Mg 3,8 3,5 4 1,7 3,2

Ca 5,9 6,7 6,6 5,4 5,9

Na

K

Ti

Mn

P

Y

La 3,4 3,6 3,7 4,8 3,3

Ce 9,8 10 9,6 11,2 8,9

Pr 1,5 0,9 0,9 0,9 1,2

Nd 5,9 4 4,2 3 5,1

Sm 0,8 0,8

Eu

Gd

Tb

Co

Cu

Br

F

Mo

Ni 0,1

Total 99,9 100 100,1 99,8 99,9

14


Weight%

Sample mork2 mork2 mork2 mork2

Mineral Törnebohmite Törnebohmite Törnebohmite Törnebohmite

Analysis Spectrum 63 Spectrum 68 Spectrum 78 Spectrum 84

C 5 6,6 3,5 4

O 27,8 28,5 29,6 29,3

S 2,1 0,7 0,3

Si 11,9 12,4 13,6 12,7

Al 3,9 4,2 4,4 4,6

Fe 2,5 0,8

Mg 0,6 0,5 0,5 0,8

Ca

Na

K

Ti

Mn

P

Y 1,1

La 8,9 9 7,2 6,5

Ce 21,8 22,4 23,4 20,7

Pr 2,4 2,7 2,9 2,7

Nd 10,5 11 13,1 12,6

Sm 1,5 1,3 1,6 3,1

Eu

Gd 0,9 1,9

Tb

Co

Cu

Br

F

Mo

Ni

Total 99,8 100,1 100,1 100

15


Weight%

Sample mork 3 mork 2 mork3 mork3 mork2 mork2 mork2

Mineral

Västmanlandite

Västmanlandite

Västmanlandite

Västmanlandite

Västmanlandite

Västmanlandite

Västmanlandite

Analysis

Spectrum 52

Spectrum 80

Spectrum 28

Spectrum 43

Spectrum 64

Spectrum 65

Spectrum 81

C 3,6 3,6 2,7 4,2 5,5 6,4 3,2

O 32,1 32,7 32,2 31,6 30,5 31,4 30,8

S 1,1 0,2 1,4 2,4 3,5 1,1 0,5

Si 13,2 14,3 13,8 13,2 12,8 14,3 13,9

Al 5,1 5,5 4,9 4,7 4,4 4,5 5,2

Fe 4,6 8,6 4,7 5,1 6,8 3,8 2,2

Mg 3,3 0,9 3,3 3,1 1,8 1,9 1,8

Ca 3,6 4,9 3,8 3,7 2,6 2,7 2

Na

K

Ti

Mn

P

Y

La 5,2 5,4 5,3 4,4 6 6,2 5,8

Ce 15,2 14,1 15 14,2 15,3 16,3 18,2

Pr 2 1,6 1,9 2 1,9 2 2,8

Nd 9,2 6,9 9,4 9,2 7,9 8,2 10,3

Sm 1,1 1,1 1,4 1,6 1,2 1 2

Eu

Gd 1,3

Tb

Co

Cu 0,7 0,5

Br

F

Mo

Ni

Total 100 99,8 99,8 99,9 100,2 99,8 100

16


Weight%

Sample mork1 mork1 mork1 mork1 mork1

Mineral Britholite-Y? Britholite-Y? Britholite-Y? Cerite? Cerite?

Analysis Spectrum 60 Spectrum 61 Spectrum 59 Spectrum 72 Spectrum 74

C 4,1 5,2 4,2 6,9 8

O 37 38,7 43,2 28,6 28,4

S

Si 16,9 16 16,3 13,5 11,5

Al 0,8

Fe 0,4 0,6 3,6 1,1

Mg 1,2 1,3 4,8 4,1 5,3

Ca 11,1 10,7 9,4 3,8 3,3

Na

K

Ti

Mn

P

Y 18,8 18,3 15,2 2,5

La 1 3,2 9

Ce 1,9 1,6 0,5 12,4 18

Pr 2 1,6

Nd 1,6 1,5 1 11,9 9,8

Sm 0,8 3,8 1,6

Eu

Gd 2,1 2,6 1,7 2,8

Tb

Co

Cu

Br

F 2,4

Mo

Ni

Total 100,1 100 99,9 99,9 100

17

Table 7. Recalculated data from SEM analyses of Knutsbo and Mörkens samples.

Weight%

Sample mork3

mork3

mork1

knut 3 mork1 mork1 mork3

mork3

Mineral Fluorcerite?

Monazite?

Fluorcerite?

Altered allanite?

Magnesiorowlandite?

Dollaseite+tremolite?

Gadolinite?

Dollaseite+quartz?

Analysis Spectrum 42

Spectrum 44

Spectrum 57

Spectrum 24

Spectrum 62

Spectrum 73

Spectrum 27

Spectrum 40

C 10,7 3,6 8,1 6,4 2,3 8,2 6,6 12,6

O 21,2 27,8 26,2 42,8 26 38,3 29,8 37,3

S 5 1,4 0,3 4,2 1,3

Si 2,8 5,9 5,8 13,2 11,4 17,6 10,1 20,3

Al 0,8 7,3 2,9 2,7

Fe 3,9 2,3 14,2 0,5 8,6 8,6 6,8

Mg 1,3 2,4 2,3 5,3 2,3 5,6 1,1 2,3

Ca 0,6 1,5 1,1 4,8 2,4 7,3 0,4 4,5

Na

K

Ti

Mn

P 8,3

Y 2,3 1,3 3

La 9,5 5,7 15,8 1,3 9,7 2,1 1,8 1,9

Ce 20,4 20,6 24,4 3,2 23,6 6,1 9,6 6,5

Pr 2,9 3 2,8 0,8 2,1 0,8

Nd 12,3 14,4 8 1,3 13 2,5 14 2,9

Sm 2,4 2,3 2,6 4,9

Eu

Gd 0,8 1,3 3,8

Tb

Co

Cu

Br

F 6,1 5,5 0,8

Mo 0,5

Ni

Total 99,9 100 100 100,1 100 100 100 99,9

18

temperature and pressure, mafic and calc-

silicate mineral assemblages are common,

which is evident in the samples with minerals

like biotite, calcite, quartz and tremolite. The

high amount of allanite in the samples can be

considered an indication of REE presence in

the samples.

With most of the mineralogy in the samples

determined by observations through

microscopy, there is an uncertainty to be

considered. Although most mineral

assemblages can be determined through their

characteristics in parallel and crossed polars of

the microscope, some are harder to classify

only from this method. Some minerals might

have gone through reactions or contain more

information that requires further studies,

which therefore have not been detected

through the observations made of these

samples.

Also the classification of opaque phases

should be considered slightly uncertain as

they were only determined from observations

in reflected light in microscope. Even here,

some characteristics could have been missed

or even disregarded if irrelevant to the

project.

5.2 SEM results The SEM results are based on a backscatter

detector with low vacuum, which was chosen

due to absence of coal coating on the

samples. The four samples chosen for analyses

showed most potential for REE-bearing

mineralisations in microscopy and the

unidentifiable mineral were the main aim for

analysis, along with its surroundings.

As rather expected, REE mineralisations were

detected in several of the samples at variable

amounts, and most of them related to

minerals of the epidote family. The minerals

with pale brown pleochroism revealed REEs

like lanthanum (La) and cerium (Ce), and REE

mineralisations like törnebohmite and

västmanlandite were discovered in two of the

samples. Dollaseite was also detected in

several of the samples.

There are some rare mineralisations that have

possibly occurred in the samples but they are

very uncertain. These include britholite-Y,

yttrium, flourcerite, monazite,

magnesiorowlandite, and gadolinite. Many of

these mineralisations are very unusual and the

calculations of their chemical formulae are

very uncertain and can therefore be

considered more as guesses than actual

classifications.

As shown in the original data from the SEM

results, the samples contain coal. Since the

samples were not coal-coated, it could be a

result of inclusions of carbonate rocks or some

carbonates in the samples.

There are quite a few uncertainties regarding

the SEM analyses and their results. The

analyses of the different samples in general

suggest plenty of impurities and therefore

made it hard to calculate and determine the

compositions of the REE minerals. This issue

could be a result of the instrument itself, not

working correctly or having the wrong settings

adapted, the thin sections themselves could

have been soiled or simply the mineralisations

in the samples themselves have gone through

alteration.

It is not possible to determine where the error

lies for these impurities only from the data

collected, and the results should therefore be

reviewed with this in mind as they are rather

uncertain. SEM analyses are not the best

method of measuring REE in general, because

of their overall low contents close to detection

limits and their energy lines partially overlap.

The presented compositions of the REE-

bearing minerals are based of recalculations of

the values from the SEM analyses, normalised

to the mole ratio of the number of cations for

the different minerals. Quite a few

assumptions have been made during these

calculations, e.g. minor elements have been

excluded and all sulphide have been assumed

to be chalcopyrite or pyrite. This did not

change the results drastically but gave a better

end result for the somewhat inferior analyses.

19

5.3 Local geology As seen in figure 1, Knutsbo is not located

directly in the extensive lens of the REE-line,

but just at the northern end of it. Due to this,

it might not show all the same geological

features as that of the rest of the REE-line.

This can be considered by overviewing a

magnetic anomaly map of the region, where

Knutsbo might as well be a continuation of the

REE-line, only dislocated.

Although not a part of this work, figure 1 as

well as 2 show a possible fault stretching

between Knutsbo and the REE-line, which

could have displaced the bedrock of Knutsbo.

If that is the case, there should be similarities

between geology and mineralogy of that of

the REE-line, which is evident in some of the

result from this report.

The general mineral assemblages in the REE-

line resembles much of those in the Knutsbo

samples. The REE mineralisations are also

similar to those of the REE-line and a

connection between them seem apparent. It is

therefore reasonable to assume Knutsbo is

related to the REE-line, based on mineralogy

and REEs.

6. Conclusions The bedrock of Knutsbo consists of granitoid-

dioritoid-gabbroid (GDG) mafic intrusive rocks,

surrounded by GDG-type granite and

granodiorite to the south and GDG-type

granodiorite in the west. The rocks have been

affected by amphibolite facies metamorphism,

and there are occurrences, probably as

xenoliths, of iron oxide deposits in the area,

including banded iron formations (BIF).

The samples collected from the Knutsbo area

have a mineralogy mainly consisting of

allanite, tremolite, quartz and actinolite. There

is a presence of a pale brown-coloured

pleochroistic mineral that has proven to be

REE-bearing. The samples contain REEs like

lanthanum, cerium and neodymium, and

appear in mineralisations like dollaseite,

törnebohmite and västmanlandite. There is

traces of yttrium, monazite, gadolinite and

other rare mineralisations but their

classifications are very uncertain. Allanite is

abundant in the samples and also one of the

REE-bearing minerals.

Out of the nine thin sections that were

studied, the samples from Mörkens proved to

be richest in REEs, while REEs were generally

low in Gruvhagen. Results of the SEM analyses

can be found in appendix.

7. Acknowledgements First and foremost, I send my greatest

gratitude to my two supervisors during this

project. Joakim Mansfeld at Stockholm

University (SU) for good guidance and great

assistance in calculations and interpretation of

the results, and to Magnus Ripa at the

Geological Survey of Sweden (SGU) for good

supervision and very helpful guidance

throughout the project. Without their advice

and constructive feedback, this report would

not have been possible.

I would also like to thank the people at the

SGU for providing me with this project and the

material necessary in form of thin sections,

maps and literature. I thank the people

involved from that department, including Per

Nysten with his help with mineral

interpretations.

Lastly, I want to thank Marianne Ahlbom at SU

for assistance during the SEM analyses, as well

as Stockholm University and the Swedish

Museum of National History in Stockholm for

allowing me to use the SEM.

20

References Andersson, U. (2004). The Bastnäs-type REE-

mineralisations in north-western

Bergslagen, Sweden. The Geological

Survey of Sweden (SGU). Östervåla:

Elanders Tofters.

Geijer, P., & Magnusson, N. (1944). De

mellansvenska järnmalmernas

geologi. Stockholm: Kungl.

Boktryckeriet.

Holtstam, D., Andersson, U., & Mansfeld, J.

(2003). Ferriallanite-(Ce) from the

Bastnäs deposit, Västmanland,

Sweden. The Canadian Mineralogist,

41, 1233-1240.

Holtstam, D., Andersson, U., Broman, C., &

Mansfeld, J. (2014). Origin of REE

mineralisation in the Bastnäs-type Fe-

REE-(Cu-Mo-Bi-Au) deposits,

Bergslagen, Sweden. Mineralium

Deposita, 933-966.

Kampmann, T. (2015). structural framework

and constraints on the timing of

hydrothermal alteration and ore

formation at the Falun Zn.Pb-Cu-(Au-

Ag) sulphide deposit, Bergslagen,

Sweden. Licentiate thesis, Luleå

Technical University.

Persson, L. (1997). Berggrundskarta 12G

Avesta SO. Sveriges geologiska

undersökning Af 189.

SGA Excursion Guidebook. (2013). Bergslagen:

Geology of the volcanic- and

limestone-hosted base metal and iron

oxide deposits. Uppsala: 12th Biennial

SGA Meeting, Excursion Guidebook

SWE4.

Stephens, M., Ripa, M., Lundström, I., Persson,

L., Bergman, T., Ahl, M., Wahlgren,

C.H., Persson, P.O. & Wickström.

(2009). Synthesis of the bedrock

geology in the Bergslagen region,

Fennoscandian Shield, south-central

Sweden. The Geological Survey of

Sweden (SGU). Ba 58, 259 p.

21

Appendix

in Wt% Spectrum 2 Spectrum 3 Spectrum 4 Spectrum 5 Spectrum 6 Spectrum 7 Spectrum 8

S 41,3 0,2 38,7 24,8 0,1

Fe 36,6 8,2 35,1 23,8 8,0 11,9 7,8

C 8,7 2,6 9,2 11,9 2,5 4,4 2,9

O 7,9 39,7 10,5 8,8 39,3 42,7 40,9

Si 2,0 16,5 3,1 3,5 17,4 23,1 17,7

Ca 1,1 10,0 1,3 1,2 11,2 7,9 11,7

Al 0,9 8,6 0,6 9,3 0,9 9,2

Co 0,8

Mg 0,7 2,8 1,5 2,6 9,0 3,0

Ce 5,7 4,2 3,4

La 3,2 1,8 2,1

Nd 2,6 2,2 1,4

Cu 24,4

Br 1,5

Tb 0,1

Pr 0,8

Sm 0,7

Mn

Table 8. Result from SEM analysis of Knutsbo sample in wt%.

22

in Wt% Spectrum 9 Spectrum 10 Spectrum 11 Spectrum 12 Spectrum 19 Spectrum 20 Spectrum 21

S 26,2

Fe 7,3 7,3 7,1 6,2 7,3 9,1 24,6

C 2,9 3,1 2,4 2,4 3,0 1,8 6,7

O 41,6 39,7 39,3 43,7 36,5 37,2 8,4

Si 17,8 17,2 17,3 25,3 14,6 15,9 2,9

Ca 11,8 10,4 10,3 9,4 7,4 10,4 1,7

Al 9,4 8,5 8,6 1,4 7,7 9,5 1,7

Co

Mg 2,9 3,4 3,5 11,4 2,5 1,3 0,8

Ce 3,4 5,3 5,4 10,6 6,6 1,0

La 1,5 2,7 2,5 4,8 3,1

Nd 1,4 2,5 2,3 4,5 3,4

Cu 26

Br

Tb

Pr 0,6 1,1 0,9

Sm 0,6 0,7

Mn 0,2

Table 9. Result from SEM analysis of Knutsbo sample in wt%.

23

in Wt%

Spectrum 57

Spectrum 58

Spectrum 59

Spectrum 60

Spectrum 61

Spectrum 62

Spectrum 71

Spectrum 72

Spectrum 73

Spectrum 74

Spectrum 75

Spectrum 76

S 41,5

Fe 34,3 0,6 0,4 0,5 12,8 3,6 8,6 1,1 3,1 12,4

C 8,1 6,7 4,2 4,1 5,2 2,3 5,1 6,9 8,2 8,0 8,5 5,0

O 26,2 8,8 43,2 37,0 38,7 26,0 34,1 28,6 38,3 28,4 42,3 34,4

Si 5,8 3,4 16,3 16,9 16,0 11,4 15,4 13,5 17,6 11,5 24,8 15,7

Ca 1,1 1,2 9,4 11,1 10,7 2,4 6,7 3,8 7,3 3,3 8,9 6,6

Al 3,9 0,8 2,9 3,6

Co 2,1

Mg 2,3 1,9 4,8 1,2 1,3 2,3 3,5 4,1 5,6 5,3 12,4 4,0

Ce 24,4 0,5 1,9 1,6 23,6 10,0 12,4 6,1 18,0 9,6

La 15,8 1,0 9,7 3,6 3,2 2,1 9,0 3,7

Nd 8,0 1,0 1,6 1,5 13,0 4,0 11,9 2,5 9,8 4,2

Pr 2,8 0,9 2,0 0,8 1,6 0,9

Sm 0,8 2,6 3,8 1,6

Y 2,3 15,2 18,8 18,3 1,3 2,5

F 5,5 0,8 2,4

Mo 0,5

Dy 2,2 2,6 2,7

Gd 1,7 2,1 2,6 1,3 2,8

Er 1,4 1,4

Table 10. Result from SEM analysis of Mörkens sample in wt%.

24

in Wt% Spectrum 77 Spectrum 78 Spectrum 79 Spectrum 80 Spectrum 81 Spectrum 82 Spectrum 83 Spectrum 84

S 24,1 0,3 33,5 0,2 0,5 31,3

Fe 21,4 27,1 8,6 2,2 24,4 14,7

C 6,3 3,5 7,8 3,6 3,2 22,6 4,6 4,0

O 11,4 29,6 13,7 32,7 30,8 14,4 33,9 29,3

Si 4,7 13,6 4,0 14,3 13,9 3,9 16,4 12,7

Ca 0,1 0,1 4,9 2,0 5,4

Al 0,8 4,4 0,6 5,5 5,2 0,3 3,1 4,6

Mg 0,6 0,5 0,5 0,9 1,8 0,5 1,7 0,8

Ce 4,2 23,4 3,8 14,1 18,2 1,3 11,2 20,7

La 1,6 7,2 1,7 5,4 5,8 0,5 4,8 6,5

Nd 2,0 13,1 1,8 6,9 10,3 0,8 3,0 12,6

Pr 2,9 1,6 0,9 2,7

Sm 1,6 1,1 2,0 3,1

Cu 22,8 5,2

Gd 1,3 1,9

Ni 0,1

Y 1,1


25

in Wt%

Spectrum 27

Spectrum 28

Spectrum 29

Spectrum 30

Spectrum 31

Spectrum 32

Spectrum 33

Spectrum 34

Spectrum 35

Spectrum 36

Spectrum 37

Spectrum 38

S 4,2 1,4 39,2 20,8 37,7 3,6 30,5 17,9 27,4 3,8 1,4 0,9

Fe 8,6 4,7 34,1 21,0 32,0 2,9 26,8 20,0 24,9 10,5 4,1 10,8

C 6,6 2,7 14,2 34,4 19,0 20,9 24,9 31,8 27,8 6,2 4,0 2,3

O 29,8 32,2 9,6 17,1 8,4 38,5 13,6 25,2 14,2 32,8 42,1 42,5

Si 10,1 13,8 1,5 2,7 1,3 21,2 1,5 2,2 2,2 13,2 25,1 25,3

Ca 0,4 3,8 0,8 1,1 0,5 3,7 0,7 0,8 1,0 5,9 8,8 8,7

Al 4,9 0,5 0,6 0,2 0,3 0,3 5,0 0,4

Mg 1,1 3,3 0,7 1,3 0,5 2,0 0,7 1,0 1,1 3,2 12,6 9,6

Ce 9,6 15,0 0,5 0,6 8,9

La 1,8 5,3 3,3

Nd 14,0 9,4 5,1

Pr 2,1 1,9 1,2

Sm 4,9 1,4 0,8

Gd 3,8

K 0,1 0,1 0,2 0,2 0,2

Y 3,0

Na 0,1 0,2

F 1,4

Co 0,4 0,6 0,4 0,6 1,0


26

in Wt% Spectrum 39 Spectrum 40 Spectrum 41 Spectrum 42 Spectrum 43 Spectrum 44 Spectrum 45 Spectrum 46 Spectrum 47

S 0,6 1,3 2,7 5,0 2,4 1,4 41,2 5,2 4,6

Fe 2,8 6,8 3,1 3,9 5,1 2,3 34,7 6,6 6,3

C 2,6 12,6 15,5 10,7 4,2 3,6 15,5 7,4 8,2

O 45,5 37,3 44,7 21,2 31,6 27,8 6,1 39,4 39,1

Si 28,1 20,3 29,5 2,8 13,2 5,9 1,3 21,5 21,2

Ca 0,8 4,5 0,2 0,6 3,7 1,5 0,3 7,7 7,4

Al 2,7 0,3 4,7 0,8 0,6

Mg 17,2 2,3 0,7 1,3 3,1 2,4 0,4 11,1 11,1

Ce 6,5 0,9 20,4 14,2 20,6

La 1,9 9,5 4,4 5,7

Nd 2,9 1,4 12,3 9,2 14,4

Pr 0,8 2,9 2,0 3,0

Sm 0,5 2,4 1,6 2,3

Gd 0,5 0,5

K 0,8

Y 0,1

Na 0,3

F 2,4 6,1 1,1 1,2

Co 8,3


27

in Wt% Spectrum 48 Spectrum 49 Spectrum 50 Spectrum 51 Spectrum 52 Spectrum 53 Spectrum 54 Spectrum 55 Spectrum 56

S 3,4 2,3 1,1 0,6 1,1 0,5 1,3 30,7 1,2

Fe 5,6 10,1 9,5 8,4 4,6 8,3 3,3 29,1 4,5

C 10,0 5,9 3,3 3,1 3,6 3,2 3,6 8,8 3,3

O 40,2 40,7 34,3 36,5 32,1 35,5 45,2 20,6 41,6

Si 21,5 23,4 14,8 15,8 13,2 15,7 26,9 4,6 24,6

Ca 7,7 8,6 5,9 5,9 3,6 5,7 0,7 2,4 8,2

Al 0,5 5,8 5,6 5,1 5,6 0,3 0,7 0,7

Mg 11,0 9,1 3,8 4,8 3,3 4,9 16,6 2,8 12,5

Ce 9,8 9,5 15,2 9,3 8,2

La 3,4 3,2 5,2 3,4

Nd 5,9 5,5 9,2 5,6

Pr 1,5 1,1 2,0 1,4

Sm 0,8 1,1 0,9

Gd 0,7 0,6

K 0,3

Y 0,2

Na 2,2 1,6

F

Co


28

Weight% oxides

Sample knut 3 knut 3 knut 3 knut 3 knut 3 knut 3 knut 3 knut 3 knut 3 knut 3

Mineral REE-poor allanite REE-poor allanite REE-poor allanite REE-poor allanite REE-poor allanite REE-poor allanite Allanite Allanite Allanite Allanite

SiO2 35,29903818 37,22444026 37,86624096 38,08017452 36,79657313 37,0105067 31,2343005 34,0154368 31,8761011 31,2343005

TiO2

Al2O3 16,24939046 17,57201527 17,38306887 17,76096167 16,06044406 16,24939046 14,5488729 17,9499081 18,3278009 15,1157121

FeO** 10,54926638 10,2919672 10,03466802 9,391420071 9,391420071 9,134120891 9,39142007 11,7071127 11,0638647 9,77736884

MnO

MgO 4,643169662 4,311514686 4,974824638 4,80899715 5,63813459 5,803962078 4,1456872 2,15575734 2,48741232 3,64820473

CaO 13,99206446 15,67111219 16,37071542 16,51063606 14,55174704 14,41182639 10,3541277 14,551747 13,9920645 10,9138103

Na2O

K2O

P2O5

NiO

Y2O3

La2O3 3,2 1,8 2,1 1,5 2,7 2,5 4,8 3,1 2,9 4,2

Ce2O3 6,676299459 4,919378549 3,982354063 3,982354063 6,207787216 6,324915277 12,4155744 7,73045201 7,37906782 11,4785499

Pr2O3 0,936254383 0,702190787 1,28734978 1,05328618 1,05328618 1,52141337

Nd2O3 3,032591436 2,566038908 1,63293385 1,63293385 2,915953304 2,68267704 5,24871595 3,96569649 3,6157821 4,89880155

Sm2O3 0,811722965 0,695762542 0,81172297 0,92768339 0,92768339

Eu2O3

Gd2O3

Tb2O3

CoO

CuO

MoO2

F

Table 16. Calculated oxide values for Knutsbo sample, in wt%

29

Weight% oxides

Sample mork 3 mork 3 mork 3 mork1 mork1 mork 2 mork3

Mineral Dollaseite Dollaseite Dollaseite Dollaseite Dollaseite Dollaseite Dollaseite

SiO2 33,8015032 33,5875697 31,6621676 32,94577 33,58757 35,0851 28,23923

TiO2

Al2O3 10,5809984 10,5809984 10,9588912 7,36891 6,80207 5,857338 9,44732

FeO** 10,8065656 10,677916 12,2217111 16,46715 15,95255 18,91149 13,50821

MnO

MgO 7,95971942 8,12554691 6,30144454 5,803962 6,6331 2,819067 5,30648

CaO 8,25531803 7,97547674 8,25531803 9,374683 9,234763 7,555715 8,255318

Na2O

K2O

P2O5

NiO 0,127259

Y2O3

La2O3 3,2 3,4 3,4 3,6 3,7 4,8 3,3

Ce2O3 11,1271658 10,8929096 11,4785499 11,71281 11,24429 13,11834 10,4244

Pr2O3 1,28734978 1,63844517 1,75547697 1,053286 1,053286 1,053286 1,404382

Nd2O3 6,41509727 6,5317354 6,8816498 4,665525 4,898802 3,499144 5,948545

Sm2O3 1,04364381 0,92768339 0,927683

Eu2O3

Gd2O3

Tb2O3

CoO

CuO

MoO2

F

Table 17. Calculated oxide values for Mörkens samples, in wt%

30

Weight% oxides

Sample mork 3 mork 2 mork3 mork3 mork2 mork2 mork2 mork2 mork2 mork2 mork2

Mineral Västmanlandite

Västmanlandite

Västmanlandite

Västmanlandite

Törnebohmite

Törnebohmite

Törnebohmite

Törnebohmite

Västmanlandite

Västmanlandite

Västmanlandite

SiO2 28,23923 30,5925 29,52283 28,23923 25,45809 26,52776 29,09496 27,16956 27,3835 30,5925 29,73677

TiO2

Al2O3 9,636266 10,39205 9,258374 8,880481 7,36891 7,935749 8,313642 8,691534 8,313642 8,502588 9,825213

FeO** 5,917881 11,06386 6,046531 6,561129 3,21624 1,029197 8,748172 4,888684 2,830291

MnO

MgO 5,472307 1,492447 5,472307 5,140652 0,994965 0,829137 0,829137 1,32662 2,984895 3,150722 2,984895

CaO 5,037143 6,856112 5,316984 5,177064 3,637937 3,777857 2,798413

Na2O

K2O

P2O5

NiO

Y2O3 1,396932

La2O3 5,2 5,4 5,3 4,4 8,9 9 7,2 6,5 6 6,2 5,8

Ce2O3 17,80347 16,51506 17,56921 16,63218 25,53392 26,23669 27,40797 24,24551 17,92059 19,09187 21,31731

Pr2O3 2,340636 1,872509 2,223604 2,340636 2,808763 3,159859 3,393922 3,159859 2,223604 2,340636 3,27689

Nd2O3 10,73071 8,048031 10,96398 10,73071 12,247 12,83019 15,2796 14,6964 9,214412 9,564327 12,01373

Sm2O3 1,275565 1,275565 1,623446 1,855367 1,739406 1,507486 1,855367 3,594773 1,391525 1,159604 2,319208

Eu2O3

Gd2O3 1,037354 2,189969 1,4984

Tb2O3

CoO

CuO 0,876244 0,625888

MoO2

F


31

Weight% oxides

Sample mork1 mork1 mork1 mork1 mork1

Mineral Britholite-Y? Britholite-Y? Britholite-Y? Cerite? Cerite?

SiO2 36,15477244 34,22937036 34,87117105 28,88103124 24,60235994

TiO2

Al2O3 1,511571206

FeO** 0,51459836 0,77189754 4,631385241 1,41514549

MnO

MgO 1,989929855 2,155757343 7,959719421 6,798927006 8,788856861

CaO 15,53119155 14,97150897 13,15254059 5,316984494 4,617381271

Na2O

K2O

P2O5

NiO

Y2O3 23,87484342 23,23987418 19,30306489 3,1748462

La2O3 1 3,2 9

Ce2O3 2,225433153 1,874048971 0,585640303 14,52387952 21,08305092

Pr2O3 2,340635957 1,872508765

Nd2O3 1,866210115 1,749571982 1,166381322 13,87993773 11,43053695

Sm2O3 0,927683389 4,406496098 1,855366778

Eu2O3

Gd2O3 2,420492481 2,996800215 1,959446294 3,227323308

Tb2O3

CoO

CuO

MoO2

F 2,4


32

Weight% oxides

Sample mork3 mork3 mork1 knut 3 mork1 mork1 mork3 mork3

Mineral Fluorcerite? Monazite? Fluorcerite? Altered allanite? Maggnesiorowlandite? Dollaseite+tremolite? Gadolinite? Dollaseite+quartz?

SiO2 5,99013981 12,6220803 12,4081468 28,23923 24,38843 37,6523074 21,60729 43,4285136

TiO2

Al2O3 1,51157121 13,79309 5,47944562 5,10155282

FeO** 5,01733401 2,95894057 18,26824 0,643248 11,0638647 11,0638647 8,74817212

MnO

MgO 2,15575734 3,97985971 3,81403222 8,788857 3,814032 9,28633932 1,82410237 3,81403222

CaO 0,83952387 2,09880967 1,53912709 6,716191 3,358095 10,2142071 0,55968258 6,29642901

Na2O

K2O

P2O5 19,018351

NiO

Y2O3 2,9208585 1,65092 3,80981544

La2O3 9,5 5,7 15,8 1,3 9,7 2,1 1,8 1,9

Ce2O3 23,8941244 24,1283805 28,5792468 3,748098 27,64222 7,1448117 11,2442938 7,61332394

Pr2O3 3,39392214 3,51095394 3,27689 0,93625438 2,45766775 0,93625438

Nd2O3 14,3464903 16,795891 9,33105057 1,516296 15,16296 2,9159533 16,3293385 3,38250583

Sm2O3 2,78305017 2,66708974 3,014971 5,68206076

Eu2O3

Gd2O3 0,92209237 1,4984 4,37993878

Tb2O3

CoO

CuO

MoO2 0,66673031

F 6,1 5,5 0,8


2016 - Karolina Mattsson - BSc - Geology 15hpKarolina Report

bachelor thesis · 2018. 6. 8. · degree project in geology 15 hp bachelor thesis stockholm 2016...

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