Insights Into Landform Genesis Based on Lithological References Provenance Studies in the Western South Andersson, G

UNIVERSITY OF GOTHENBURG Department of Earth Sciences Geovetarcentrum/Earth Science Centre

PROVENANCE OF PEBBLE

CLASTS IN HUMMOCKS IN

THE EASTERN SOUTH SWEDISH

HIGHLANDS NEAR GULLASKRUV

Martin Thor Karin Grodzinsky

ISSN 1400-3821 B931 Bachelor of Science thesis Göteborg 2016

Mailing address Address Telephone Telefax Geovetarcentrum Geovetarcentrum Geovetarcentrum 031-786 19 56 031-786 19 86 Göteborg University S 405 30 Göteborg Guldhedsgatan 5A S-405 30 Göteborg SWEDEN

Table of contents Introduction ...... 3 Aim of study ...... 3 Research question ...... 3 Study site & geology ...... 3 Bedrock geology ...... 3 Deglaciation of southern Sweden ...... 7 Acquisition and transport of glacial debris ...... 7 Hummocks ...... 8 Hummocks in Gullaskruv ...... 9 Esker formation ...... 9 Methodology ...... 10 Field work ...... 10 Lab work ...... 10 Results ...... 12 Rock descriptions ...... 12 Provenance studies ...... 14 CHI2 test ...... 14 Provenance markers...... 14 Shape analysis ...... 15 Discussion...... 17 Provenance study ...... 17 CHI2-test ...... 18 Difference between eskers and hummocks ...... 18 Shape analysis ...... 20 Hummock formation ...... 20 Conclusions ...... 21 Further studies ...... 21 Acknowledgements ...... 22 References ...... 22 Appendices ...... 24

Abstract Hummocks occur in many forms in southern Sweden. However, the genesis of these landforms has not fully been understood. The new LiDAR dataset covering Sweden is a new source of information with large possibilities for giving further insight on the genesis of many glacial landforms, including hummocks. Provenance studies of sediment in hummocks on the south Swedish highlands, near Gullaskruv, suggest a very local provenance where granites, rhyolites and porphyries from the Transscandinavian Igneous Belt predominate. Some of the furthest transported clasts are inferred to come from the Vetlanda group and nearby basalt formations, 70 km away. Shape analysis on clasts from the hummocks imply that the sediment composing the hummocks is similar to sediment of known subglacial origin. Lithological provenance studies and shape analysis suggests that the clasts have been locally eroded, entrained and deposited with a maximum transportation distance of 70 km. The studied samples have been compared statistically and lithologically to samples with the same grain size from eskers in order to strengthen a possible transportation mechanism. The difference that was found between the hummocks and the eskers can probably be traced back to that the sediment in the two types of landforms had different transport routes and distances.

Sammanfattning Hummocks förekommer i många former i södra Sverige. Men bildningen av dessa landformer har inte helt förståtts. Den nya LiDAR-datan över Sverige är en ny källa till information med stora möjligheter att ge ytterligare insikt om uppkomsten av många glaciala landformer, bland annat hummocks. Provenansstudier av sediment från hummocks på Sydsvenska höglandet, nära Gullaskruv, föreslår en mycket lokal härkomst där graniter, ryoliter och porfyrer från Transskandinaviska magmatiska bältet dominerar. Några av de längst transporterade klasterna kan härledas att komma från Vetlandagruppen och närliggande basaltformationer, 70 km bort. Shape analys på klaster från dessa hummocks antyder att moränen som utgör dessa landformer liknar sediment av känt subglacialt ursprung. Litologiska provenansstudier och Shape analys tyder på att dessa klaster har blivit lokalt eroderade, transporterade och avsatta med en maximal transportsträcka på 70 km. De studerade proverna har blivit jämförda statistiskt och litologiskt med prover med samma kornstorlek från rullstensåsar för att stärka en möjlig transportmekanism. Skillnaden som påträffats mellan hummocksen och rullstensåsarna kan troligtvis spåras till att sedimentet i de två landformerna hade olika transportvägar och transportavstånd.

Keywords: hummocky terrain, esker, South Swedish Highlands, provenance, glacial geomorphology, LIDAR

Introduction Research question What is the provenance of the sediment in Hummocks and associated landforms occur these “fish scale” hummocks? widely on the south Swedish highlands. They are a type of glacial landform which are Is there a significant statistical difference enigmatic and widely discussed. Many between the clasts in the studied hummocks different theories have been presented and eskers in the area? If so, can this help in regarding their genesis, and it is likely that determining the genesis of the hummocks? similar forms can be made by more than one These two groups of samples will be examined process. To simplify, there are a few different separately and compared to each other in theories on their formation: One theory order to establish whether or not a significant suggests that debris-rich ice is thrusted at the statistical difference can be found between top of the glacier and later on deposited as hills them. when the glacier melts (Johnson & Clayton, 2003). Another where they are interpreted as Study site & geology supraglacial and, or subglacial deposits, where The area studied in this thesis lies on the south till is melted out from a stagnant ice (Johnson Swedish highlands in Småland, Kalmar län, et al., 1995). Still another is one where the approximately halfway between Växjö and hummocks are interpreted to form when Kalmar in Nybro municipality (Fig. 1). The study subglacial debris is thrusted to a en- or area lies within an area bounded by supraglacial position. This debris is then 56°54'33.5"N, 15°39'17.8"E and 56°51'15.3"N, collapsed down when the ice melts, in an active 15°40'49.1"E. Sampling was made at three ice setting, creating hummocks (Hambrey et hummocks and three eskers, in the study area al., 1997). Previously, the hummocks in the which is shown in Fig. 1. The studied hummocks south Swedish highlands have been considered are highlighted in Fig. 2. stagnant ice deposits, for example by Andersson (1998), Möller (2010) and Möller & Dowling (2015). The New National Elevation Model (NNH) consists of LiDAR (Light Detection and Ranging) data with complete coverage over southern Sweden. This data is utilized by Gustaf Peterson, PhD student at Gothenburg University and SGU (Swedish Geological Survey), with the purpose of shedding light on how these hummocks are formed. The LiDAR data has revealed hummocks in many previously unknown forms, whose origin and Figure 1. Map over southern Sweden. The black dot marks genesis are to be investigated. the study area in this thesis.

Aim of study Bedrock geology This thesis will examine if lithological The descriptions of the bedrock in the study provenance studies and clast shape analysis area will be focused on western Småland, pre- can help provide insight into and help identify dominantly the Jönköping province and parts the genesis of the “fish scale” (a working term) of Kronoberg and Kalmar provinces (Fig. 3). hummocks studied by Peterson at a site called Gullaskruv, se Fig. 1.

The bedrock in the study area is part of the Transscandinavian Igneous Belt (TIB), which started to form in the Paleoproterozoic era between 1,8 -1,9Ga BP. It was formed when the Eurasian plate collided with the North American plate (Högdahl et al, 2004). It is one of the larger structural units that constitute the Baltic shield, the large craton that holds Scandinavia, Finland and the Baltic countries. The TIB reaches north from Småland up through Värmland and Dalarna, with a few occurrences in the Scandinavian mountains, see Fig. 4.

Figure 2. LiDAR Hillshade DEM over the study area. The studied hummocks are highlighted by the red square. The eskers are highlighted with blue lines.

Figure 3. Map over the study area showing the different bedrock classes found in the studied hummocks. The black star marks the location of the study area. Modified after Bergman et al. (2012).

commonly gray to reddish gray. The granites and rhyolites in this area often carry phenocrysts and are porphyritic in their texture (Wik et al., 2007). The rhyolites in the area are commonly slightly younger than the granitic rocks, but often dated to 1,8 Ga (Lundqvist et al., 2011). Porphyry is often considered a subvolcanic rock and often occur in contact zones between intrusive and extrusive rocks. Their grain size can often be somewhere between the fine grained granites and the rhyolites (Thomas Eliasson, personal communication)

Close to the Protogine zone, which separates the Eastern segment in the west from the TIB in the east (Fig. 4), rocks are commonly deformed and metamorphosed (Wik et al., 2006). These deformed rocks also occur in the Oskarshamn-Jönköping belt (OJB), outside of Jönköping (Lundqvist et al., 2011).

According to the Wik et al. (2006) there are several bodies of mafic extrusive rock scattered Figure 4. Map over the Baltic shield, where the across the region. These bodies occur mostly in Transscandinavian igneous belt is highlighted in red (Lundqvist et al., 2011). the Jönköping province, close to the Vetlanda and Almesåkra formations (Vetlanda light blue The bedrock is characterized by intrusive and and Almesåkra dark blue in Fig. 3). A basalt extrusive felsic rocks belonging to the TIB 1 composition is most common, but there is stadium (1,81-1,76 Ga) (Lundqvist et al., 2011). some andesite occurring as well. There are also The intrusive rocks are of granitic composition some areas with intrusive gabbroic rocks and are, in some areas, very fine grained, scattered across the TIB. These rocks because they were recrystallized when commonly show signs of magma mixing extrusive rocks intruded in immediate structures, resulting from mixing with the proximity to the granites (Thomas Eliasson, granitoid country rock. Mafic hypabyssal personal communication) and in areas with varieties also occur, where diabase (dolerite) is contact to the porphyries (Lundqvist et al., the most common. They can predominantly be 2011). These granites (unit 108 in Fig. 3) are found in the Almesåkra formation where the mapped as red to gray-red, fine to finely mafic rocks are slightly younger than the medium grained granite (Wik et al., 2007). In sedimentary rock bodies they surround. other areas medium grained syenitic granite is However, several large dikes and sills are common with larger grains of quartz and scattered across the region in long north-south potassium feldspar, and SGU has mapped running dikes across the landscape. these rocks as red to gray red, medium to coarse granites. The extrusive rocks are There are several stratigraphic units that are prominently of rhyolitic composition, with composed of sedimentary rock in the TIB. The some cases where dacitic rocks occur. The three largest are the Visingsö Group (approx. rhyolites are commonly red to pink in color, 800-700 Ma), Almesåkra Group (at least 970 with a very fine grained matrix. The dacites are Ma) and Vetlanda Group (1830-1800 Ma)

(Lundqvist et al., 2011). The rocks from the Lundquist & Wohlfarth (2001) to ~13.9 ka yr Visingsö Group (dashed yellow area, unit 14 in BP, and have therefore been deposited Fig. 3) are commonly fine grained and quartz sometime between the formation of the rich. They are not as compressed and hard as Halland and Gothenburg moraines. The area other sedimentary rocks in the area, since they with the moraines lies directly west of the have not endured the same grade of studied area and can therefore be considered metamorphism (Wik et al., 2006; Thomas to be relevant for this study. Eliasson, personal communication, 2016). Anjar et al. (2014) used 10Be exposure dating in Rocks from the Almesåkra group are much order to provide dates that does not only more compacted, and comprised of both represent the minimum age of deglaciation, quartz arenite and arkose (Wik et al., 2006). but when the ice actually left the area. This Rocks with a jotnian sandstone texture occur in study has been conducted across all of this area (Nationalencyklopedin, 2016). The southern Sweden. In their study, Anjar et al. Vetlanda group is characterized by wackes, (2014) conducted exposure dating in areas sandstones, and some conglomerates that north and south of Gullaskruv, close to Lake have all been metamorphosed to some extent Åsnen and Sjöanäs. The dates produced in their (Wik et al., 2006). All of these sedimentary work show that the ice sheet passed over the rocks are at least 150 Ma years older than area sometime between 15.6 ka yr BP and 16.9 those found in the Lower Paleozoic sandstones ka yr BP. These isotope dates of rocks have from Västergötland. The Visingsö Group was yielded very inconclusive results, which could formed at the latest 700 Ma (Lundqvist et al., either originate from errors in the method or 2011) and the Västgöta sandstones were be explained by that the ice either re-advanced deposited during the Cambrian period or left in a very irregular or stagnant way. (Bergman et al., 2012). Deglaciation of southern Sweden Acquisition and transport of glacial About 20-19 ka yr BP, during the LGM (Last debris glacial maximum), the ice sheet over When an ice sheet is advancing across a Scandinavia started to retreat (Clark, et al. landscape, the glacier acquires sediment and 2009). It reached down to northern Germany transports it further away from its source. and covered Sweden and parts of Denmark. According to Benn & Evans (2010) these clasts The ice sheets retreat has been well have three different ways of entrainment and documented and compiled in several papers, transportation: (1) supraglacial, where rock among others Lundqvist & Wohlfarth (2001) debris is deposited on top of a glacier by and Anjar et al. (2014). The retreat is well avalanches or rock fall. These clasts are later on documented along the western coast of transported on the top of the ice until they are Sweden where several end moraines have deposited. Material from underneath the ice been dated. The Halland coastal moraines have can also be thrusted up in the ice and carried in been dated to 14.1- 14 ka yr BP and the a supraglacial position over large distances; (2) Göteborg moraine is dated to 12.7 to 12.6 yr BP englacial, where the clasts can have the same (Lundquist & Wohlfarth, 2001) The southern entrainment principle as supraglacial material Swedish highlands do not have continuous with avalanches, but are later covered by moraines which can be seen as troublesome accumulating snow and ice on top of them. The when discussing the deglaciation. However, same thrusting mechanic as with supraglacial there are some 14C dating of clay varves material can also create englacially transported performed by Björck & Håkansson (1982) from material; and (3) subglacial, where the material lake Trummen, close to Växjö. These varves is dragged along underneath it or in the basal have been interpreted and corrected by debris-rich zone within the ice.

Puranen (1988) concluded that clast transport When the ice left the area these melt out distance varies depending on both transport features were created when the debris-rich ice time as well as glacier velocity. Clasts melted away slowly. transported en- or supraglacially can therefore Andersson (1998) conducted a travel farther since the ice creep movement is sedimentological study of hummocks in the faster there. This can lead to that the area close to lake Bolmen, approximately 120 provenance of the clasts vary in the km from Gullaskruv. He argued that the stratigraphy when supraglacial material is hummocks in this area were formed by deposited on top of basal material. supraglacial material accumulating in Hummocks depressions at the top of the ice. This material Hummocky glacial deposits in Småland have could possibly have been thrusted up from the almost exclusively been interpreted as bottom of the ice due to a re-advance. This stagnant ice deposits (Andersson, 1998; later resulted in an inversion of the landscape. Hebrand & Åmark, 1989; Möller, 2010). The former depressions in the ice now Stagnant ice is ice that has been left behind as appearing as hills and knobs scattered across the ice sheet retreats and which is no longer the landscape. An illustration of this principle flowing. These interpretations have also been can be seen in Fig. 5. made by Möller and Dowling (2015) who described hummocks in southern Sweden as stagnant ice deposits. Their study was conducted with the help of LiDAR data, and they have described two different zones landform where the deposits have certain characteristics. One zone is described as ribbed and hummocky moraine, and the other is described as a streamlined terrain, which contains drumlins and other streamlined features. Hummocks occur in between the streamlined features, which is also the case with the hummocks in this study. In their study, Möller & Dowling (2015), classified their hummocks as stagnant ice glacial deposits with an elongation ratio of less than 2, which means that the length of the formation must be smaller than twice that of the width.

Hummocks and their formation have been a topic of discussion in geology. Generally, hummocks have been interpreted as some form of collapse of supraglacial material Figure 5. Supraglacial formation of hummocks by infilling of sediment in depressions and later inversion of the (Johnson and Clayton, 2003). These hummocks landscape. From Benn & Evans (2010). typically have rather chaotic shapes and formations. In addition to the supraglacial Hambrey et al. (1997) argues that some collapse origin, other studies have argued for hummocks formed both in Scotland and on other processes. Johnson et al. (1995) Svalbard are the result of thrusting in a poly- conducted a study in Wisconsin, USA, arguing thermal glacier. Subglacial material is thrusted that the hummocks in their study area are up from the bottom of the glacier and carried formed by melt-out from basal debris-rich ice. in an englacial or supraglacial setting. The till is

later deposited when the glacier melts, and the suggests that these hummocks were formed by deposits form hills and knobs that follow each subglacial processes. other in a train. An example of this can be seen The hummocks at the study site near in figure 6. Gullaskruv (Fig. 7) have a somewhat regular pattern, which is uncommon in stagnant ice, collapse-type hummocks as described previously in the area. These hummocks are wedge shaped with a steep side pointing towards SSE. The hummocks have somewhat of a fan-shape or triangular shape where the steep side of the hummocks is the thinnest and they widen on their flat side. These wedges of hummocks seem to overlap each other which is the origin of the name “fish scale” hummocks. Their length range from 100m to 30m and are typically around 70m long. Their widths wary between 70m to 30m.They are typically around 6-7m tall, but slight variations occur.

Figure 6. Hummock formation by thrusting according to Hambrey et al. (1997). Johnson and Clayton (2003) also discuss the possibility of subglacially deposited and formed hummocks. They list several different ways that other papers have discussed how hummocks could have been formed subglacially. They include pressing of ice blocks in a stagnant setting into a deformable bed and an active ice subglacially molding hummocks, rogen-moraines and drumlins. Hummocks in Gullaskruv The new LiDAR images show that the hummocks have a wide variety of shapes including several recognizable types. Because of this variety, it is likely that different Figure 7. Close up of the hummocks in Fig. 2. The green dots symbolize the sampling sites. hummocks forms may have different origins. Thus, the genesis of some of these hummocks Esker formation has to be reconsidered. The work being Eskers are long, elongate glacial landforms produced by Gustaf Peterson aims to utilize created when an ice sheet retreats over a this new data in order to clarify whether or not landscape and deposits glacifluvial material there are other possibilities of genesis for the along the way through large meltwater hummocks in the area. For example: A channels (Benn & Evans, 2010). These hummock near Hörda studied by Dahlgren meltwater channels or tunnels are eventually (2013) and Grodzinsky & Thor (2016) is overlain filled by the glacifluvial sand and gravel and a by an esker, which along with other signs ridge is created when the ice has fully melted. The meltwater channels can either be en-, sub-

, or supraglacial. The length of the ridges is arbitrarily chosen as the grain-size fraction for controlled by whether or not the material is collection. The clasts with approximately the deposited by a normal retreat of the ice, by a right size that were in close proximity to the 50 surging glacier or if the glacifluvial material is cm mark were collected. They were then deposited into a subaqueous fan. The two placed in a sampling bag that was labeled latter cases can result in stubby, short esker- MTGE-XX for eskers or MTGH-XX for sections spread out over the landscape. hummocks. Hebrand and Åmark (1989) have studied eskers in the vicinity of the study area. They infer that the eskers were formed by subglacial processes, and not in open supraglacial channels. Their study area lies in the northern part of Skåne, south of the area studied in this thesis. GIllberg (1968) concluded that sediment and clasts deposited in eskers often are previously transported subglacially by the glacier. Eskers can therefore be considered to be composed of secondary sediments. Gillberg (1968) also concluded that a long transport of the glacifluvial material will result in a large variety of lithologies. Figure 8. Sampling during field work in Gullaskruv, Småland.

Methodology The span of the clasts size is rather large seeing Field work that the clasts with different sizes could have Sampling sites were selected using SGUs travelled different lengths. However, this could application GEOKARTAN with a LiDAR map and compromise the random selection since the a Hillshade cover to locate old cuts, i.e. gravel method with the measuring tape is dependant pits, road cuts, into the glacial landforms. Sites on picking the clast closest to each 50 cm mark. where Gustaf Peterson had already done If this method was not performed, the excavations and logging were also used. Mark ramndomness of the test would not be the Johnson and Gustaf Peterson helped identify same which would compromise the CHI2-test. hummocks and eskers that were suitable for Lab work sampling. The samples were washed and scrubbed with a The sampling took place at several different fiber brush in a lab in order to get rid of clay and locations, in close proximity to Gullaskruv. Five lichen. The washed samples were put in labeled samples from hummocks and five samples boxes in order to keep them separated from from eskers were collected during the field each other and avoid possible contamination. work (Fig. 7). Two of the sampling sites were A large part of the work consisted of the sampled twice since they were located in classifications of different rock types. In order favorable excavations. Each of the samples to determine which rock classes to assign to contained approximately 100 rock samples the different rocks, local bedrock geology maps each. from Wik et al. (2006) & Wik et al. (2007) were The rocks were selected randomly by placing a utilized along with the expertise from SGU. The measuring tape in front of an exposure, and rock classes that were finally used were: Basalt, rock samples were taken every 50 cm, see Fig diabase, gabbro, granite, pegmatite, porphyry, 8. A phi size of -5 to -6 (32 to 64mm) was rhyolite, sandstone, TIB granite and quartzite.

Ulf Bergström, Lena Lundquist and Thomas After samples were classified, a measurement Eliasson, geologists from SGU, Göteborg, of their long A-, intermediate B- and short C- supervised part of the classification of the axes were made with calipers and roundness different rock types. They, among other things, was estimated for use in a shape analysis helped show the difference between rhyolites according to Sneed & Folk (1958) and Powers and granites, which in the study area have very (1953). The categories used for roundness similar characteristics. These geologists have were Very Angular (VA), Angular (A), Sub- been part of a team mapping the area Angular (SA), Sub-Rounded (SR), Rounded and previously. Their knowledge was essential in Very Rounded (VR). The samples were entered order to ensure that the classifications were individually into an excel sheet designed by made correctly. Graham & Midgley (2000) in order to calculate the samples C40 index. C40 index is the portion A hand lens was utilized during the of clasts where the axis ratio c/a is ≤ 0.4. The classifications along with a magnetic pen. samples RA indices were calculated by dividing Sometimes a hammer was used in order to the amount of angular and very angular clasts examine a fresh surface. To preserve and with the total amount of clasts. This was done document the rocks original shape for the in order to compare the samples to the control shape analysis, this procedure was performed samples established and utilized by Lukas et al. after the axes of the clast were measured. (2013). Some of the samples were cut with a rock saw in order to either highlight good examples of Lithology and shape data was collected, certain rocks or see a fresh surface of a rock compiled and processed in Microsoft Excel, that was too hard to break with a hammer. where a CHI2-test was performed. A CHI2-test Samples that were of special interest, stood examines whether the lithologies of the out from the rest or were good examples of a samples are significantly different by certain rock type were labeled and recorded in calculating the expected amounts for each an excel sheet. An example from the parameter observed. classifications can be seen in Fig. 9.

Figure 9. All rock samples from sample GH02 during the classification.

Results Rock descriptions Fine grained extrusive rocks with a mafic composition where classified as basalt (Fig. 10). These rocks are commonly weathered on the outside. Their color is black or very dark grey, sometimes with a hint of green or blue when Figure 10. Basalt sample from an esker. weathered.

Rocks with a mafic composition with small grains of white plagioclase, albite, in a dark matrix were classified as a diabase (Fig. 11). These rocks were commonly very hard. Some of them had an ophitic texture.

Rocks with an albite matrix and small mafic grains were classified as gabbro (Fig. 12). These Figure 11. Diabase sample from an esker. rocks could also be of a diorite or granitoid composition, but that distinction has not made. Metamorphosed samples are included in this category.

A large number of the rocks classified as granite (Fig. 13) have a composition that resembles syenite or a syenite granite. A distinction has Figure 12. Gabbro sample from a hummock. not been made as suggested by the SGU geologists. Rocks classified as granite are commonly fine grained and the tags X, Y, Z has been applied when the rock is of granitic composition but differs from the rest of the granites. A P-tag has been added to some of the clasts if they contained some phenocrysts or had a minor porphyric texture, a G or M tag has Figure 13. Granite sample from a hummock. been added if the sample shows signs of metamorphism or it has a gneissic texture. A common denominator of these rocks is that they have a texture that is aplitic or close to aplitic.

Rocks with very large homogenous grains of either quartz or potassium feldspar were classified as pegmatite (Fig. 14).

Some of the rocks with a granitoid composition were hard to distinguish from each other. Since Figure 14. Pegmatite sample from an esker. there are a lot of felsic extrusive rocks that have formed simultaneously to the granites in they are of an intrusive or extrusive origin. the area (Lundqvist et al., 2011), there are a lot These rocks have been classified as porphyry of rocks that are hard to differentiate whether (Fig. 15) since that is often used as a

nomenclature for sub volcanic or hypabyssal rocks with a granitic composition. The origin of these rocks was hard to establish since they have a lot of characteristics similar to both rhyolite and granite. All of these samples had large phenocrysts of quartz, potassium feldspar or plagioclase, embedded in a finer matrix, which are characteristic for porphyries. Figure 15. Porphyry sample from an esker. Rocks with a very quartz rich composition and high metamorphic texture, and some small mafic grains have been classified as quartzite (Fig. 16).

The rhyolites (Fig. 17) in the samples commonly have a very fine grained matrix, undetectable without magnification. Some samples are even glassy in their texture. A pink to dark red color is common. They almost always contain Figure 16. Quartzite sample from an esker. phenocrysts. A P-tag has been added to samples with very prominent phenocrysts. A D- tag has been added to samples with a grey color that appeared to be of dacitic composition. These samples are commonly gray, but a distinction was not made. Samples that had been metamorphosed or had a mylonitic texture were labeled with an M-tag. Figure 17. Rhyolite sample from an esker. Sandstone (Fig. 18) occurs in some samples. They primarily stem from the Almesåkra group (unit 95 in Fig. 3), but some less compacted, samples have been interpreted to be from the Visingsö group (unit 14 in Fig. 3). Commonly they are fine grained and mostly quartz arenitic in their composition. A J-tag has been added to one sample that has a texture that bears resemblance to Jotnian sandstone. A C tag has been added to samples that have the Figure 18. Sandstone sample from an esker. Good characteristics of sandstone deposited during example of rock from the Visingsö group. the Cambrian. Samples with a silt matrix have been labeled with an S tag. Conglomerates have also been found in the samples. They are often somewhat metamorphosed, which is common for rocks from the Vetlanda (unit 111 in Fig. 3) and Almesåkra formations. There are some conglomerate bodies in the eastern part Figure 19. TIB granite sample from an esker. of this region. These rocks commonly have a sandy or silty matrix with embedded coarser

clasts. These rocks have been classified as Basalt, gabbro, granite and porphyry are more sandstone for the statistic test in this thesis. common in the hummock samples. But pegmatite, conglomerate, gneiss and quartzite Rocks classified as TIB granite (Fig. 19) have did not occur at all. In the samples from eskers, characteristic medium to coarse grains of Rhyolites and TIB granites are more numerous quartz and potassium feldspar, which is typical than in the hummock samples. of the rocks formed in the Transscandinavian Igneous Belt. CHI2 test The result from the CHI2-test is shown in Table Provenance studies 2 where P denotes the significance level. A The summary of the lithological classifications significance level of 0.05 is often utilized as a for all the esker samples and all the hummock delimiter if there is a significant difference samples are shown in Table 1 and Fig. 21. between the two datasets. A lower number Table 1. Result from the classification of rock samples means that there is a significant difference from eskers (GE) and hummocks (GH). between the two samples, which there is in this test. Rocktype GE GH Basalt 6 8 Table 2. Results from the CHI2-test

Diabase 3 3 Observed Basalt Granite Porphyry Rhyolite Other TIB granite TOTAL Gabbro 3 5 GH 8 218 141 110 9 37 523 GE 6 69 29 319 22 59 504 Granite 69 218 TOTAL 14 287 170 429 31 96 1027 Pegmatite 6 0 Expected Basalt Granite Porphyry Rhyolite Other TIB granite TOTAL Porphyry 29 141 GH 7,130 146,155 86,573 218,468 15,787 48,888 523 Quartzite 2 0 GE 6,870 140,845 83,427 210,532 15,213 47,112 504 TOTAL 14 287 170 429 31 96 1027 Rhyolite 319 110 P 7,02E-55 Sandstone 8 1 Provenance markers TIB granite 59 37 In several cases, the lithologies can be traced to Total 504 523 specific localities and specific mapped rock The esker samples show a wide diversity of units, and these interpretations have been rocktypes. Several different types of rocks are corroborated in conversation with the SGU represented, where basalt occurred in almost geologists mentioned above. The Jotnian all of the samples. The rhyolites are by far the sandstone from sample GE02 is inferred to most common rock type. The two different come from the Almesåkra group (unit 95 in Fig. types of granites and porphyry also occur quite 3). frequently, but not nearly as abundantly as the rhyolites.

The samples collected from the hummocks are not as diverse in different rock types as the samples from eskers. The most common rock type is the fine-grained type of granite. Porphyry and rhyolite also occur in large quantities. However, the three most abundant rocks show a more even distribution. The TIB granites are not as common as in the esker Figure 20. Jotnian sandstone from the Almesåkra group. samples, but still occur in every esker sample. The basalt sample in Fig. 10. is inferred to come The histogram in Fig. 21 highlights the from the basalt formations south or east of the differences between the two types of deposits. Vetlanda group (unit 112 in Fig. 3).

The sandstone in Fig. 18. is inferred to come had much lower C40 values, 4-10%. The RA- from the Visingsö group (unit 14 in Fig. 3). indices are low to non-existant in the esker samples but range from 30-50% in the Shape analysis hummocks. The shape analysis resulted in tri-plots where each triangle represents one sample (Fig. 23 & The different samples RA and C40 indices were 24). plotted against each other in a covariant plot (Fig. 22) in order to compare with Benn & Evans The samples from the eskers has C40 indices in (2010) and Lukas et al. (2013). the 10-30% range, but the hummock samples

70,0% 63,3%

60,0%

50,0% 41,7% 40,0%

30,0% 27,0%

21,0% 20,0% 13,7% 11,7%

10,0% 5,8% 7,1% 1,5% 0,6% 0,6% 1,0% 1,2% 0,4% 1,6% 1,2% 0,6% 0,0% 0,0% 0,2% 0,0% Basalt Diabase Gabbro Granite Pegmatite Porphyry Quartzite Rhyolite Sandstone TIB granite

GE GH

Figure 21. Bar plot showing a side by side comparison of the two samples rock type distribution in percentages.

1,00 0,90 0,80 0,70 0,60 0,50 GH

RA RA index 0,40 0,30 GE 0,20 0,10 0,00 0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 C40 index

Figure 22. Co-variant plot of RA and C40 indices for the different samples plotted against each other. 15

Figure 23. Results from the shape analysis. From top left GH01, GH02, GH03, GH04 & GH05. The tri-plots were used to calculate C40 and the bar plots in each top right corner shows the distribution of roundness.

Figure 24. Results from the shape analysis. From top left GE01, GE02, GE03, GE04 & GE05. The tri-plots were used to calculate C40 and the bar plots in each top right corner shows the distribution of roundness.

Discussion type could be classified and origin determined were interpreted to be very local. The different Provenance study granites from the TIB are of local origin and it is It is hard to exactly pinpoint the outcrops a very improbable that they would come from large portion of the rock samples from the another area in Sweden or Norway. The TIB hummocks originated from. However, all of extends up through Värmland, Dalarna and them were determined to have a very local parts of Norway, but those rocks have very signature. None of the rocks in the samples dissimilar characteristics to the ones found in have been identified as being transported very Småland and are not as fine grained. The same far, more than 70 km. principle should also apply to the porphyries. Porphyry, rhyolite, granite and TIB granite are They are very common in Dalarna, but given considered to be locally eroded and. These the very local signature of the other rocks, it is rocks occur in the immediate proximity of the highly improbable that they have traveled that glacial deposits and do not have to travel a very far. The only rocks that had to have been long distance in order to end up in the transported over a greater distance are the hummocks or eskers. The origin of pegmatite basalts. The only large basalt bodies found in and diabase are harder to pinpoint since there the local bedrock geology are the basalt bodies are many basalt dikes and quartz and near the Vetlanda formation, approximately 70 pegmatite veins in the area. The diabase rocks kilometers away. are possibly from the Almesåkra group, but the The single sandstone found in the hummock age for the dikes and the large formations in samples was very hard and probably somewhat the Almesåkra group have the same age. Thus, metamorphosed or at least compacted. This even if a chemical analysis were to be would indicate that the rock originates from conducted, it would be hard to exactly the Almesåkra or Vetlanda formation. Taking determine their origin. Sandstone and basalt the suggested transport route in Fig. 25 into are not per se locally eroded, since there are no account, it would be probable that this occurrences in the immediate proximity to the sandstone is from the Vetlanda group. The studied hummocks or eskers. But their hardness of this rock type would allow it to be provenance has been determined to be from transported over a large distance or even the area in, or close to, the sedimentary survive a previous deposition and re- deposits in the Jönköping province. Thus, rocks transportation. The same is also true for the from the Visingsö group would have to travel basalts. They were all somewhat rounded about 130 kilometers in order to end up in the which could point towards re-deposition and esker deposits where they were found. The transportation from a previous glaciation or gabbroic samples could stem from various transportation mechanism. This would further gabbro bodies in the area, and it is impossible lower the transportation distance for the to say from which one without further chemical hummocks. The studied hummocks must be analyses. The quartzite observed in the considered locally eroded and transported samples are much more deformed than the given these factors. hard sandstone originating from the Almesåkra formation, suggesting that this is not their origin. Hence, its origin cannot be fully determined.

The hummock samples also contain a lot of local rocks with similar lithologies as in the esker samples, even though the composition is different. Most of the rocks in which the rock

CHI2-test Difference between eskers and The CHI2-test yielded a significant difference hummocks between the esker samples and the hummock The black lines in Fig. 25 represent the possible samples. This could suggest that the samples transport routes for the eskers. They have been have different provenance. However, the fact drawn on top of eskers from SGUs soil surficial that both of the landforms contain very local maps obtainable through SGUs service rock types suggests that both of the sample Geolagret. The lines have been interpolated groups are still largely locally eroded, entrained where there were no eskers. Esker deposits and deposited. The large significant difference pass through the extrusive rock formation could stem from the fact that the deposits are close to the sampling sites and does only enter in close proximity to a contact zone between the intrusive granite batholites after a couple rhyolite and granite and that the different of miles. The black lines should not be landforms have been created by different interpreted as long complete eskers, but as a transport routes in the ice or in the subglacial possible transportation route for the tunnel systems. This would explain the meltwater tunnels under the ice. However, different composition of the hummocks and these could just as well not be representative eskers, while maintaining the observation that for the tunnels during the entire time of they both are locally eroded, entrained and deglaciation because esker deposits are time deposited, see Fig. 25. transgressive. But, the extended inferred esker deposits pass through all of the different rock

Figure 25. Bedrock map from SGU over the extended study area. Green dots symbolize the extent of the sampling area. The blue lines represent eskers mapped by SGU. The black line are inferred esker transportation routes. The green line is the suggested transportation directon of the hummocks. The circles show where the different lithological probably originated from.

types found in the eskers, which would make by two different transportation methods have this a viable transportation route and explain a larger opportunity to travel a longer distance. the significant difference between the It could be argued that the increased amount hummock and esker deposits from the CHI2- of rhyolites in the eskers stems from that the test. Based on the hummocks appearance, way transport may comminute different rock general ice sheet retreat movement and which types at different rates. The granites and rock types that were found, the dark green line porphyries transported glacifluvially would is a suggested route that the ice could have therefore have had to be broken and eroded at moved. a higher rate. The samples from the eskers A remarkable observation in the esker samples were much more rounded than those from the is that they are composed of a large majority of hummocks and by that reasoning, more rhyolites (63,3%) but at the same time have a abraded. But the chemical composition and large distribution of different kinds of rock hardness of the rhyolites, granites and types. This implies that the ice forming the porphyries are too similar for this effect to be eskers eroded a lot of rhyolites during their fully acceptable as a reason for the difference. formation, but also eroded quite a large area. The fact that the different rock types were not Gillberg (1968) concluded that long eskers observed or studied in situ is undesirable and often contains varying lithologies, which fits something that could have been done to give very well in this case. The eskers west of the more legitimacy to the thesis. This could have hummocks would have been formed in tunnels been done by collecting control samples from where the ice had eroded the rhyolites at a outcrops in the field and comparing these to greater extent. The Jotnian sandstone found in the clasts found in the eskers and the sample GE02 likely originates from the hummocks. However, it can be argued that the Almesåkra group, since the sample contains assistance from geologists from SGU during the both feldspar and quartz and is very hard. The classifications negates any effect this would more loosely packed sandstone found in the have on the project’s result. same sample was likely eroded from the Visingsö group. This suggests that the eskers According to Puranen (1988) the are capable of transporting material over a vast transportation distance of clasts can vary in the distance, even though most of the material is vertical stratigraphy of the formation. The locally eroded. clasts at the top could have been transported further if they were carried higher up inside or The wider range of different lithologies on top of the ice. The sampling method used in occurring in the eskers could infer that the area this thesis does not account for this effect since of erosion and transportation is larger for the the measuring tape was laid out horizontally eskers than the hummocks. This would further across the formation. This could lead to that strengthen that the hummocks are a very the samples all displayed signs of one kind of locally eroded and transported landform, transportation distance. However, the which would point at subglacially transported collected clasts showed signs of both short and debris. This becomes even more clear when long transport so this effect could be taking the different maximum transportation considered negated and the results valid and distances into account, ~130 km for eskers and representable. A sampling section with a ~70km for hummocks. Eskers are often thought vertical direction could have been performed of as being secondary deposits as suggested by in order to compare to the rest of the samples. Gillberg (1968) which could explain that some This could strengthen the results even further. clasts seem to have been transported over a very long distance. Clasts that are transported

Shape analysis The shape analysis shows that there is a large difference in roundness between the clasts that were deposited in a hummock and those that were deposited in an esker. Their C40 indices were also very different. When comparing the covariant plot of the RA- and C40 indices in Fig. 23, to the control samples from Lukas et al. (2013) (Fig. 26), it can be found that the samples from this thesis plots very similarly to the subglacially transported gneiss samples in their study. The gneiss Figure 26. Covariant plots of control samples from Lukas samples from their study have to be considered et al. (2013) with the results from the shape analysis the most relevant in this study, since the from this study plotting inside the circles. The orange majority of the lithologies found in the samples circle for the hummocks and the blue circle for the eskers. are of granitic composition. The esker samples In many ways, the Gullaskruv hummocks from this study can also be utilized in these resemble the ones studied by Hambrey et al. covariant plots. If they are compared to (1997) both in morphology and clast shape. fluvially transported material in the same Hummocks like these are inferred to be formed control samples from Lukas et al. (2013) it can by active ice which is in direct conflict to the be noted that these samples have very similar many observations of stagnant ice deposits in RA- and C40 indices. The shape analysis the area (Hebrand & Åmark, 1984; Möller supports a fluvial history for the esker 2010). It is a possibility that this proposed sediment and a subglacial history for the thrusting is a local occurrence in an otherwise hummock sediment. Significantly, the shape stagnant ice setting. But, the landscape is analysis does not show that the material from dominated by drumlins and other streamlined the hummocks is similar to scree or landforms, indicating subglacial activity. A re- supraglacial material, indicating that the advance into a stagnant ice could possibly hummock sediment is subglacial or did not produce thrusting large and prominent enough occur in a supraglacial position for any length in order to create these hummocks, but it of time. In order to be considered to be would have to be very local or small in order to supraglacially transported material or scree, maintain the rest of the stagnant ice features. the angularity of the rocks should also have If active ice is involved, it likely played a role in been much higher, according to Benn & Evans the orthogonal structure displayed by the (2010). hummocks (Fig. 7). Hummock formation Andersson (1998) suggested that the When considering the very local provenance of hummocks in his area in western Småland were the clasts and the result from the shape formed by supraglacial deposition of rock analysis (Fig. 23) it stands clear that the debris on top of stagnant ice. The till is argued hummocks must have been formed by locally by Andersson (1998) to be in a supraglacial eroded rock fragments that at least initially position due to thrusting occurring during a re- were transported subglacially. advance of the ice. This corresponds very well with both the shape of the Gullaskruv hummocks, the subglacially transported material according to the clast shape analysis and the stagnant ice setting of the area around it. The theory proposed by Andersson (1998)

does include the stagnant ice setting in the area suggests that the clasts were not glacifluvially (Möller, 2010; Möller & Dowling, 2015) which transported and that a supraglacial transport is Hambrey et al. (1997) does not. A re-advance highly unlikely given the very local provenance into stagnant ice could also help explain the of the majority of the rocks. “Fish scale” pattern in the hummocks as a result of till being deposited on top of a Conclusions stagnant ice and inverting the landscape when The hummocks in the study are composed of it melts away. Even if the suggested genesis of clasts that has been eroded in an area very hummocks in the area does not quite fit the close to the deposits. The hummocks were Gullaskruv hummocks, does not mean that likely formed in a stagnant ice setting where their investigations are wrong. The Gullaskruv the ice sheet re-advanced and thrusted “Fish scale” hummocks are a very local type of subglacial material was left behind with the feature which has not been observed before. stagnant ice. This material has probably not So, even if they do not fit perfectly with the been transported supraglacially for a long time previously suggested origin for hummocks in but has been thrusted up onto the ice during a the area, these previous theories are not in any re-advance. The hummocks in the area has way disproven by this study. previously been suggested to have been If these hummocks were to be formed by melt formed when the stagnant ice with till on top out like the ones suggested by Johnson et al. of it melted away causing an inversion of the (1995) they would need to have a larger landscape. It could be argued this is the case amount of clasts transported over a long even for these hummocks. Results from the distance. The melt out hummocks are often shape analysis and the local provenance of formed by basal debris from the base of the rocks found in the hummocks suggest that they glacier. The provenance study cannot fully rule have been transported subglacially over a fairly out that this is a possible explanation of the short distance. The shape of the hummocks, Gullaskruv hummocks, but this would have to which can be observed in the LiDAR images, be proven by other studies and more also corresponds with this theory as they investigations. resemble those found by Andersson (1998). The stagnant ice setting of the area as indicated A formation by squeezing as described by by Möller (2010) and Möller & Dowling (2015) Johnson & Clayton (2013) seems unlikely given also fits in very well with this theory. the shape of the hummocks. In the LiDAR pictures, they seem to overlap each other. This There is a significant difference between the would be easier to explain if they were to be rock types of the hummocks and eskers in the formed by a stagnant ice with debris thrusted area. They are however both comprised of up between the stagnant ice segments. predominantly locally eroded rocks. The difference could be explained by an alternate All previous studies in this area have been transport route for the eskers, as well as a concluding that the glacial landforms in the longer transport distance. area are the result of a stagnant ice. It could be the case for the hummocks, but it has to be Further studies argued that these hummocks could very well Further sedimentological research is being be the result of a supraglacial deposition, if it conducted by Gustaf Peterson for Gothenburg has been done by thrusting. In order to University and SGU. In terms of provenance establish whether they have been formed by studies some chemical analyses would be squeezing, melt out or another medium, more helpful in order to establish provenance, sedimentological studies will have to be especially in some of the sandstones and performed. However, the shape analysis highly diabases. Radiometric dating on some clast

which provenance were hard to pinpoint could Dahlgren, S. (2013). Subglacially meltwater also be useful to further improve the results in eroded hummocks (Master thesis). this study. Gothenburg: Department of Earth Science, University of Gothenburg.

Acknowledgements Gillberg, G. (1968). Lithological distribution and We would like to thank our supervisor Mark homogeneity of glaciofluvial material. GFF, Johnson and Gustaf Peterson for their help, 90(2), 189-204. both in the field and with designing this thesis. We would also like to thank Thomas Eliasson, Graham, D. J., & Midgley, N. G. (2000). Lena Lundquist and Ulf Bergström at SGU for TECHNICAL COMMUNICATION-Graphical their help during the rock type classifications. Representation of Particle Shape using Their help was invaluable. Andreas Karlsson Triangular Diagrams: An Excel Spreadsheet also provided a lot of help during the Method. Earth Surface Processes and classifications and definitely deserves a Landforms, 25(13), 1473-1478. mention. Grodzinsky, K., & Thor, M. (2016). Insights into landform genesis based on lithological References provenance studies in the western South Andersson, G. (1998). Genesis of hummocky Swedish highlands near Hörda. (Bachelor of moraine in the Bolmen area, southwestern Science thesis). Department of Earth Sciences, Sweden. Boreas, 27(1), 55-67. Gothenburg University.

Anjar, J., Larsen, N. K., Håkansson, L., Möller, P., Hambrey, M. J., Huddart, D., Bennett, M. R., & Linge, H., Fabel, D., & Xu, S. (2014). A 10Be‐ Glasser, N. F. (1997). Genesis of ‘hummocky based reconstruction of the last deglaciation in moraines’ by thrusting in glacier ice: evidence southern Sweden. Boreas, 43(1), 132-148. from Svalbard and Britain. Journal of the Geological Society, 154(4), 623-632. Benn, D. I., & Ballantyne, C. K. (1993). The description and representation of particle Hebrand, M., & Åmark, M. (1989). Esker shape. Earth Surface Processes and Landforms, formation and glacier dynamics in eastern 18(7), 665-672. Skane and adjacent areas, southern Sweden. Boreas, 18(1), 67-81. Benn, D., & Evans, D. J. (2010). Glaciers and glaciation. Routledge. Högdahl, K., Andersson, U. B., & Eklund, O. (Eds.). (2004). The Transscandinavian Igneous Bergman, S., Stephens, M.B., Andersson, J., Belt (TIB) in Sweden: a review of its character Kathol, B. & Bergman, T., (2012). Bedrock map and evolution (Vol. 37). Geological survey of of Sweden, scale 1:1 million. Sveriges Finland. geologiska undersökning, K 423 SGU, Uppsala. Johnson, M. D., Mickelson, D. M., Clayton, L., & Björck, S., & Håkansson, S. (1982). Rediocarbon Attig, J. W. (1995). Composition and genesis of dates from Late Weichselian lake sediments in glacial hummocks, western Wisconsin, USA. south Sweden as a basis for Boreas-International Journal of Quaternary chronostratigraphic subdivision. Boreas, 11(2), Research, 24(2), 97-116. 141-150. Johnson, M.D., & Clayton, L. (2003). Clark, P. U., Dyke, A. S., Shakun, J. D., Carlson, Supraglacial landsystems in lowland terrain, in A. E., Clark, J., Wohlfarth, B., Mitrovica, J. X., Evans, D.J.A., ed., Glacial Landsystems, Arnold, Hostetler, S. W. & McCabe, A. M. (2009). The London p. 228-258. last glacial maximum. science, 325(5941), 710- 714.

Lukas, S., Benn, D. I., Boston, C. M., Brook, M., Nationalencyklopedin, jotnisk sandsten. Coray, S., Evans, D. J., Graf, A., Kellerer- http://www.ne.se/uppslagsverk/encyklopedi/l Pirklbauer, A., Kirkbride, M. P., Krabbendam, ång/jotnisk-sandsten (retrieved 2016-05-09) M., Lovell, H., Machiedo, M., Mills, S. C., Nye, K., Reinardy, B. T., Ross, F. H. and Signer, Powers, M. C. (1953). A new roundness scale (2013). Clast shape analysis and clast transport for sedimentary particles. Journal of paths in glacial environments: A critical review Sedimentary Research, 23(2), 117-119. of methods and the role of lithology. Earth- Science Reviews, 121, 96-116. Puranen, R. (1988). Modelling of glacial transport of basal tills in Finland. Espoo: Lundqvist, J., Lundqvist, T., & Lindström, M. Geological Survey of Finland. Sneed, E. D., & (2011). Sveriges geologi från urtid till nutid. Folk, R. L. (1958). Pebbles in the lower Colorado Student literature. River, Texas a study in particle morphogenesis. The Journal of Geology, 114-150. Lundqvist, J., & Wohlfarth, B. (2000). Timing and east–west correlation of south Swedish ice Wik, N.-G., Andersson, J., Bergström, U., marginal lines during the Late Weichselian. Claeson, D.T., Juhojuntti, N., Kero, L., Quaternary Science Reviews, 20(10), 1127- Lundqvist, L., Möller, C., Sukotjo, S. & Wikman, 1148. H. (2006). Beskrivning till regional berggrunds-

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Appendices Appendix 1. Full results from the classifications of the samples from hummocks.

GH01 GH02 GH03 GH04 GH05 TOTAL Diabase 2 Basalt 6 Granite 62 Granite 58 Basalt 2 Basalt 8 Gabbro 1 Gabbro 4 Porphyry 9 Granite E 1 Diabase 1 Diabase 3 Granite 33 Granite 23 Rhyolite 25 Granite Z 3 Granite 9 Gabbro 5 Granite M 2 Granite P 6 TIB granite 3 Porphyry 23 Granite P 5 Granite 218 Granite P 15 Granite X 1 Rhyolite 11 Porphyry 70 Porphyry 141 Porphyry 18 Porphyry 21 Rhyolite P 1 Rhyolite 5 Rhyolite 110 Rhyolite 19 Rhyolite 42 TIB granite 3 Rhyolite P 3 TIB granite 37 Rhyolite P 3 Rhyolite P 1 TIB granite 15 Sandstone 1 TIB granite 10 Sandstone M 1 Total 523 TIB granite 6

Appendix 2. Full results from the classifications of the samples from eskers.

GE01 GE02 GE03 GE04 GE05 TOTAL Basalt 1 Basalt 2 Basalt 2 Basalt 1 Conglomerate 1 Basalt 6 Conglomerate M 1 Conglomerate 1 Gabbro 2 Diabase 2 Porphyry 12 Diabase 3 Granite G 2 Diabase 1 Gabbro M 1 Granite 15 Rhyolie WT 1 Gabbro 3 Granite 21 Granite 7 Granite 10 Granite 1 Rhyolite 55 Granite 69 Granite M 1 Granite P 2 Granite T 2 Granite G 1 Rhyolite C 1 Pegmatite 6 Granite P 1 Pegmatite 2 Pegmatite 2 Granite P 4 Rhyolite D 3 Porphyry 29 Porphyry 9 Porphyry 1 Porphyry 4 Granite T 2 Rhyolite M 2 Quartzite 2 Rhyolite 52 Quartzite 1 Quartzite 1 Pegmatite 2 Rhyolite P 5 Rhyolite 319 Rhyolite M 2 Rhyolite 67 Rhyolite 63 Porphyry 3 Rhyolite R D 1 Sandstone 8 Sandstone J 1 Rhyolite B 1 Rhyolite D 3 Rhyolite 39 Rhyolite WT 3 TIB granite 59 TIB granite 9 Rhyolite D 1 Rhyolite D M 1 Rhyolite C 1 Sandstone 1 Total 504 Rhyolite M 1 Rhyolite M 5 Rhyolite D 1 TIB granite 16 Rhyolite P 1 Sandstone 1 Rhyolite M 1 TIB granite K 1 Rhyolite WT 2 TIB granite 5 Rhyolite P 2 TIB granite 10 Rhyolite P WT 1 Rhyolite WT 4 Sandstone 2 TIB granite 18