Master s thesis Linda Lundgren Supervisor: Charlotte Möller, Jenny Andersson, Mattias Göransson & Jan Erik Lindqvist

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1 Master s thesis Linda Lundgren Supervisor: Charlotte Möller, Jenny Andersson, Mattias Göransson & Jan Erik Lindqvist Department of Geology

2 Outline Introduction: aim, geological setting, domain descriptions Methods Results Conclusions 2

3 Introduction Natural gravel deposits Objectives Qualitative and quantitative analyses Qualitative results prospecting tools 3

4 Introduction -Regional geology Sveconorwegian Orogen -Accretion and continentcontinent collision c. 500 km wide orogenic belt -Consist of five segments -High grade metamorphism ( Ga) Modified from Bingen et al. (2008) 4

Introduction -Regional geology Eastern Segment - Three tectonic levels - Granitic to syenitoid gneisses (1.81-1.

5 Introduction -Regional geology Eastern Segment - Three tectonic levels - Granitic to syenitoid gneisses ( Ga) -Younger protholith rocks: -mafic dykes (1560 Ma) -felsic to mafic intrusions ( Ma) -granite to syenitoid intrusions ( Ma) - Affected by pre- Sveconorwegian high-grade metamorphism at Ga Data collected from the bedrock database at the Geological Survey of Sweden 5

6 Introduction -Geology of the Falkenberg area Varberg granulite gneiss domain: -High-T metamorphism and charnockitization (1.4 Ga) -Characteristics (in the field): -Dark color -Veins are sparse -Relict igneous textures -Lack metamorphic segregation -Characteristics (in thin section): -Low biotite content -Antiperthitic plagioclase -Red-brown biotite -Brown-green hornblende -Orthoclase occur as augen -Pyroxene are present -Titanite + tartan twinning are absent Data collected from the database at the Geological Survey of Sweden 6

K-feldspar augen relict coarse grained Lack lineation and distinct

7 Introduction -Geology of the Falkenberg area Varberg granulite gneiss domain Dark color (reddish grey) Veins are sparse and extensive Pink K-feldspar augen relict coarse grained Lack lineation and distinct metamorphic segregation Lithological layering Sample from Ljungby (LL1103) 7

Brown-green hornblende Titanite and tartan twinning are absent Orthoclase

8 Introduction -Geology of the Falkenberg area Varberg granulite gneiss domain Low content of biotite Antiperthitic plagioclase Red-brown biotite Brown-green hornblende Titanite and tartan twinning are absent Orthoclase occurs as augen Clinopyroxene Ljungby, thin section LL1103 F2 Red scale bar = 1mm 8

9 Introduction -Geology of the Falkenberg area Hallandia gneiss domain: -One or two vein generations (1.43 and 0.97 Ga) -Two generations of granite pegmatite dykes (1.40 and 1.45 Ga) -Polymetamorphic -Characteristics (in the field): -Reddish grey -Pronounced lineation and foliation -Extensively veined and folded -Characteristics (in thin section): -Antiperthitic plagioclase -Red-brown biotite -Brown-green hornblende -Orthoclase occurs occasionally -Pyroxene + tartan twinning are rare -Titanite is absent Data collected from the database at the Geological Survey of Sweden 9

10 Introduction -Geology of the Falkenberg area Reddish grey color Hallandia gneiss domain Pink augen and veins are common, the latter is folded The lineation is more pronounced than the foliation Sample from Knobesholm (LL1104) 10

and pyroxene are absent Tartan twinning is rare Hallandia

11 Introduction -Geology of the Falkenberg area Antiperthitic plagioclase Red-brown biotite Brown-green hornblende Titanite and pyroxene are absent Tartan twinning is rare Hallandia gneiss domain Knobesholm, thin section LL1104 PL Red scale bar = 1mm 11

12 Introduction -Geology of the Falkenberg area Skene migmatite gneiss domain: -Stromatic migmatitic gneisses -Characteristics (in the field): -Metamorphic segregation -Often lack relict igneous texture -Unstrained leucosome veins are abundant -Local folding of veins and layering -Characteristics (in thin section): -Tartan twinning is common and well developed -Dark brown biotite -Blue-green hornblende -Biotite occurs as aggregates, bands and individual grains -Titanite is present -Antiperthite, orthoclase +garnet are rare Data collected from the database at the Geological Survey of Sweden 12

mesosome) No primary igneous textures or folding Unstrained

13 Introduction -Geology of the Falkenberg area Skene migmatite gneiss domain Stromatic banding (segregation of leucosome and mesosome) No primary igneous textures or folding Unstrained leucosome veins (minerals show sugary texture) Sample from Töresjö (LL1109) 13

individual grains Titanite is present Garnet is rare Antiperthite and hornblende are absent

14 Introduction -Geology of the Falkenberg area Skene migmatite gneiss domain Tartan twinning is common and well developed Dark brown biotite Biotite occurs as aggregates, bands and individual grains Titanite is present Garnet is rare Antiperthite and hornblende are absent Orthoclase occurs as core in few microcline augen Red scale bar = 1mm Töresjö, thin section LL1109 F1 14

15 Introduction -Geology of the Falkenberg area Svarten gneiss domain: -Roughly N-S trending structure -Characteristics (in the field): -Heterogeneous -Pronounced lineation -Commonly veined -Relict igneous textures occur locally -Characteristics (in thin section): -Antiperthite is common -Albite twins poorly developed -Red-brown biotite -Brown-green hornblende -Clinopyroxene + garnet are present -Titanite + tartan twinning are absent Data collected from the database at the Geological Survey of Sweden 15

16 Introduction -Geology of the Falkenberg area Svarten gneiss domain Stretching lineation and relict igneous textures are present Lack migmatitic structures and veins Gneissic layering Sample from Köinge (LL1112) 16

biotite Brown-green hornblende Tartan twinning and titanite are absent

17 Introduction -Geology of the Falkenberg area Svarten gneiss domain Antiperthitic plagioclase Albite twins are poorly developed Red-brown biotite Brown-green hornblende Tartan twinning and titanite are absent Clinopyroxene and garnet are present Red scale bar = 1mm Köinge, thin section LL1112 TL 17

18 Methods - Technical analyses Studded tyre test (A N, SS-EN ) - Resistance to abrasion MicoDeval test (M DE, SS-EN ) - Resistance to abrasion Los Angeles test (LA, SS-EN ) - Resistance to fragmentation High values poor rock quality 18

19 Methods -Water absorption analysis Standard EN 13755: - A b = ((m s -m d )/m d ) g accuracy - High A b indicates high amount of fractures mechanical behavior of the rock 19

20 Methods -Preparation of thin sections Two thin sections per sample (24 solid rock thin sections) Cut parallel and perpendicular to the lineation (PL and TL respectively) and perpendicular to the foliation (F1 and F2) Minoprep (Hunnebostrand): - Impregnated with flourescent dye - Polishing 20

21 Methods - Micro analyses Image analysis: - Carl Zeiss Vision KS400 image analyzing software mosaic images Microcrack analysis: - Combined images with traverse lines - Intragranular, transgranular and grain boundary cracks - Cavities are excluded Mineral grain size analysis : - Polarized images with traverse lines, 200 grains were counted - Minimum, maximum and mean mineral grain size Mineral grain size distribution analysis : - Cumulative distribution curves for each sample (programmed excel sheet according to NT BUILD 486) 21

22 Methods - Micro analyses Perimeter analysis: - More fine grained material has a higher perimeter - NIS Element BR 3.10 software - Objects are classified into group of phases Foliation index (FIX): - Define the degree of foliation - Polarized images and traverse lines - FIX = (P L ) / (P L ) // - Anisotropic rocks have a FIX value >

23 Methods -Chemical analyses Fridhemsberg (LL1108) and Töresjö (LL1109) were exluded Acme Analytical Laboratories (method 4A and 4B) - Major elements (Si, Al, Fe 3+, Mg, Ca, Na, K, Ti, P, Mn and Cr), REE and refractory elements TriPlot software plot normative mineralogy: - QAP diagram GCD toolkit 2.3 software plot bulk chemical mineralogy: - R1-R2 diagram - Total Alkali Silica (TAS) diagram - P-Q diagram No point counting 23

24 Results -Technical properties LL1101= Dagsås LL1103= Ljungby LL1105= Hallandssten LL1107= Abild LL1109= Töresjö LL1111= Vräk LL1102= Stavsjö LL1104= Knobesholm LL1106= Mokrik LL1108= Fridhemsberg LL1110= Toppeberg LL1112= Köinge 24

25 Results -Water absorption A b < 0.5 wt % rock material is frost resistant (SS-EN A1) A b 1 wt % rock material is suitable as aggregates for railway (SS-EN ) No correlation to the technical properties 25

26 Results - Microcracks LL1101= Dagsås LL1103= Ljungby LL1105= Hallandssten LL1107= Abild LL1109= Töresjö LL1111= Vräk LL1102= Stavsjö LL1104= Knobesholm LL1106= Mokrik LL1108= Fridhemsberg LL1110= Toppeberg LL1112= Köinge 26

27 Results -Mineral grain size and mineral grain size distribution LL1101= Dagsås LL1103= Ljungby LL1105= Hallandssten LL1107= Abild LL1109= Töresjö LL1111= Vräk LL1102= Stavsjö LL1104= Knobesholm LL1106= Mokrik LL1108= Fridhemsberg LL1110= Toppeberg LL1112= Köinge 27

28 Results -Perimeter -Perimeter LL1101= Dagsås, LL1102= Stavsjö, LL1103= Ljungby, LL1104= Knobesholm, LL1105= Hallandssten, LL1106= Mokrik, LL1107= Abild, LL1108= Fridhemsberg, LL1109= Töresjö, LL1110= Toppeberg, LL1111= Vräk and LL1112= Köinge 28

29 Results -Foliation index (FIX) Anisotropic rocks have a FIX value > 1.10 No correlation to the technical properties 29

30 Results -Chemistry Modified from Le Maitre (1989) LL1101= Dagsås LL1103= Ljungby LL1105= Hallandssten LL1107= Abild LL1111= Vräk LL1102= Stavsjö LL1104= Knobesholm LL1106= Mokrik LL1110= Toppeberg LL1112= Köinge Modified from De La Roche et al. (1980) 30

31 Results -Chemistry Modified from Middlemost (1985) Modified from Debon & Le Fort (1983) LL1101= Dagsås LL1102= Stavsjö LL1103= Ljungby LL1104= Knobesholm Correlates to density and LL1105= Hallandssten LL1106= Mokrik LL1107= Abild LL1110= Toppeberg the LA/A N ratio LL1111= Vräk LL1112= Köinge 31

32 Conclusions Samples from Dagsås (LL1101) and Ljungby (LL1103), located in the Varberg granulite gneiss domain, are the most suitable materials as aggregates for roads (bounded road layers) and railways, while samples from Fridhemsberg (LL1108) and Töresjö (LL1109), located in the Skene migmatite gneiss domain, are the least suitable. Knobesholm (LL1104) and Vräk (LL1111) are suitable as aggregates for bounded road layers. Features in the field that can be used as prospecting tools for rocks with good technical properties are: the absence of 1) a pronounced stretching lineation 2) high grade metamorphic banding (segregation of light and dark minerals) and 3) abundant veining. Features, on a microscopic scale, which indicate a high-t (granulite) metamorphism and result in good technical properties are: 1) low biotite content, 2) reddish brown biotite, 3) brownish green hornblende, 4) antiperthitic feldspars, 5) pyroxene, and 6) the absence of titanite and tartan twinning in feldspars. A high content of biotite and the occurrence of biotite as individual grains, aggregates and/or bands parallel to present foliation correlate with poor technical values. 32

33 Conclusions Low mean grain size and high perimeter (total, amphibole + pyroxene and opaque minerals + garnet) show a good correlation to low LA values. A high proportion of very fine (c. 40 % < 0.5 mm) or fine grained materials (80 % < 1mm) seem to contribute to good LA values. The frequency of fractures has limited influence on the LA value where less fractures often result in better technical values. Samples with high density tend to have a lower LA/A N ratio. 33

34 Acknowledgement Supervisor: Charlotte Möller (LU) Co-supervisors: Jenny Andersson (SGU) Mattias Göransson (SGU) Jan Erik Lindqvist (CBI) Karin Appelquist (CBI) & Björn Schouenborg (CBI) 34

35 Thank you for listening 35

9/4/2015. Feldspars White, pink, variable Clays White perfect Quartz Colourless, white, red, None

9/4/2015. Feldspars White, pink, variable Clays White perfect Quartz Colourless, white, red, None ENGINEERING GEOLOGY Chapter 1.0: Introduction to engineering geology Chapter 2.0: Rock classification Igneous rocks Sedimentary rocks Metamorphic rocks Chapter 3.0: Weathering & soils Chapter 4.0: Geological