relict non glacial surfaces in formerly glaciated landscapes abstract relict non glacial surfaces occur within many formerly glaciated landscapes and contain important information on past surface processes and long term landscape evolution relict non glacial surfaces are distinguishable from glacial surfaces by large scale morphologies including rounded summits fluvial valleys and cryoplanation terraces and pediments and the presence of tors blockfields and or saprolites preservation during glaciation occurs either through coverage by non erosive cold based ice or as nunataks although surface morphologies and denudation rates indicate a continuous non glacial surface history since preglacial times relict non glacial surfaces are dynamic features that have evolved during the quaternary depending on spatial variables such as lithology slope regolith depth and the abundance of fine matrix and water some surfaces are denuding very slowly while others display more rapid denudation high spatial variability in denudation rates results in changing surface morphologies over time denudation rates also display high temporal variability with much surface evolution having perhaps occurred soon after the initial onset of glaciation or during paraglacial phases while some parts of non glacial landscapes are currently active others may be largely inactive relicts of past higher energy regimes although non glacial surfaces are dynamic much remains to be determined regarding surface denudation rates and the magnitude of morphological changes over time

comparison of radiocarbon dating of buried paleosols using arbuscular mycorrhizae spores and bulk soil samples ten paleosols from four separate soil pits located in karkevagge a glaciated trough in swedish lapland were dated using radiocarbon each soil was dated using both conventional bulk soil organic material som and a pure sample of arbuscular mycorrhizae am fungal spores the latter are produced by ubiquitous mycorrhizal fungi associated with the roots of many plant genera and may be viewed as a fossil material that has not interacted with any soil constituent subsequent to its emplacement in the soil at a time presumed to mark the cessation of a favorable soil forming environment regional deglaciation is presumed to have been about 10 000 bp while a cosmogenic exposure date obtained from the valley floor in karkevagge dated at 13 100 1638 bp the youngest paleosol buried at similar to 6 cm in soil pit m3 produced a spore date of 0 281 cal yr bp 1 sigma however bulk som dates of the same paleosol a horizon gave widely divergent dates and varied with the sample pretreatment ie the combustion temperature and the acid base treatment for example the bulk som dates for that paleosol ranged from a post bomb date of 0 314 cal yr bp 1 sigma to 2366 2710 cal yr bp 1 sigma when subjected to different pretreatments acid only acid base acid and the ignition temperatures 400 800 or 900 degrees c the oldest paleosol in the set buried at similar to 61 cm in soil pit m6 dated at 5479 5698 cal yr bp 1 sigma using spores but beyond calibration using bulk som the spore dates were all within the range to be expected of postglacial paleosols but the bulk som dates were frequently beyond the generally accepted time of deglaciation in addition all of the spore dates followed a conventional age depth pattern while the bulk som dates did not there are known possible sources of geogenic carbon contamination in karkevagge which may well account for the obviously invalid older bulk som dates an additional complication is that the spore dates vary somewhat with their density and diameter however where other types of fossil or charcoal are unavailable it appears that the enormously broad distribution of spores and their lack of interaction within the soil and persistence may well offer the prospect of an unusually useful radiocarbon dating medium within paleosols

chemical weathering of mafic rocks in boreal subarctic environment northwest russia under influence of glacial moraine deposits abstract chemical weathering of mafic rocks represents substantial sink of atmospheric co2 yet the mechanismes of this process in high latitude regions are poorly understood this work addresses geochemical migration and partitioning of major and trace elements between rock soil and surface waters during chemical weathering of mafic rocks and soil formation under the influence of a glacial moraine in the northwestern russian subarctic we used multidisciplinary approach which included major and trace element chemical analysis sr isotopic measurements and mineralogical structural and microscopic investigations quaternary pleistocene deposits were observed even in the deepest horizons of soil profiles and confirm a strong moraine influence as most soils showed podzolic features chemical and sr isotopic analyses revealed a strong impact of the moraine on soil chemistry and mineralogy mineralogical studies showed the presence of non aeolian quartz and zircon in soils which were not linked to the nature of the parental rocks i e mafic and felsic at the same time we observed the presence of etch pit corrosion on the surface of zircons and feldspars and a newly formed matter adjacent to the surface of primary phases the chemical index of alteration cia showed weak or no weathering of rocks within the soil profile and the weathering intensity scale confirmed the felsic chemical composition of soils developed over mafic and ultramafic rocks analysis of sr radiogenic isotopes demonstrated preferential removal of easily weatherable and less radiogenic minerals over the full depth of soil profile and a more radiogenic signature of the granitic moraine compared to mafic and felsic bedrocks the composition of most surface waters reflected the weathering of silicate rocks but did not allow for distinguishing purely mafic source the chemical weathering rates of ultramafic rocks were calculated to be higher than those for the granitic till but the moraine depositions which dominate this region hide evidence of the real weathering process this could be due to retention of mg and ca in soil due to precipitation of secondary phases such as mg vermiculite or divalent cation adsorption on mineral organic or organo mineral phases as a result weathering rates estimated for the olivinite rock appear to be lower than the weathering rates of mafic rocks reported in other boreal and subarctic regions overall the felsic moraine deposits are capable to sizably decrease the weathering intensity of mafic rocks which should be taken into account for chemical weathering modelling of high latitude regions subjected to glaciation in the past

pyrite enhanced chemical weathering in karkevagge swedish lapland conventional wisdom once held that weathering in cold climates was overwhelmingly due to physical processes however that convention was challenged when chemical weathering was identified but unexplained as the dominant landscape denudation process in karkevagge an alpine valley in swedish lap land the research reported here involved scanning electron microscopy and energy dispersive x ray fluorescence of rock coatings to investigate chemical weathering in karkevagge analyses revealed that white coatings associated with streams emerging on the valley cliff face are commonly an amorphous aluminum oxyhydroxide sulfate such as basaluminite al 4 so 4 oh 10 h 2 o efflorescence on seasonal vegetation in stream channels demonstrates that this is an active process the white coating chemistry exhibited no systematic spatial patterns along the valley axis or with position on the cliff face although the white coatings were not crystalline and did not contain appreciable amounts of fe or ca in sheltered overhangs among boulders on the valley floor there were other well crystallized secondary sulfate minerals commonly associated with pyrite oxidation including gypsum jarosite and amorphous fe compounds this difference is due presumably to the ph of the associated waters because fe compounds tend to precipitate only at ph 5 which is the ph of the stream water pyrite oxidation may be an important early weathering process in this and in many other environments however it largely goes unrecognized because it occurs relatively rapidly in a geological sense and typically is only identified in recently disturbed landscapes associated with mining or other large scale earth moving activities karkevagge demonstrates that subarctic conditions do not preclude intense chemical weathering where conditions are favorable but it does not establish that strong chemical weathering is a widespread attribute of subarctic conditions

ice sheet erosion and the stripping of tertiary regolith from baffin island eastern canadian arctic abstract the erosion of glaciated regions and concomitant changes in ice sheet dynamics through the pleistocene are poorly documented the baffin island landscape which has been shaped by the foxe sector of the laurentide ice sheet lis contains a variety of glacial and proximal glaciomarine sedimentary archives spanning the pleistocene we examine these records to better understand when tertiary regolith was stripped from beneath the foxe sector of the lis till on the interior plateaux of the island in areas with scoured bedrock have low chemical index of alteration cia values low meteoric 10 be 10 be met concentrations and clay mineralogy consistent with erosion from an unweathered bedrock source however in some areas in between fiord onset zones more weathered till is present containing considerably higher cia values high 10 be met concentrations and secondary clay mineral weathering products implying that the till has persisted on the landscape and weathered during successive glaciations using these weathering signatures we analyze the coastal glaciogenic deposits of the clyde foreland formation cff at two sites for evidence of tertiary regolith removal from the interior of baffin island by lis erosion provenance indicators within the cff demonstrate that pleistocene lis ice flow lines across baffin island have remained generally constant the oldest cff glaciogenic unit likely representing one of the first if not the first lis advances across baffin island had high 10 be met concentrations at the time of deposition consistent with extensive regolith erosion evidence of notably weathered sediment is absent in all younger units suggesting that tertiary regolith was likely largely stripped from the interior of the island by 1 6 0 2 ma

geologic nitrogen and climate change in the geochemical budget of karkevagge swedish lapland abstract while nitrogen is an essential nutrient for plant growth in the terrestrial environment and generally fixed by biological processes in soils in arctic and alpine environments n is a severely limited nutrient because of both climatic and soil constraints it is widely believed that geologic nitrogen is such a small component of the nitrogen cycle that this source is generally not viewed as being a significant component however it has been estimated that in fact as much as 20 of the total nitrogen budget may be stored in geological materials and where n is severely limited such as in arctic and alpine environments geologic n may in fact be a dominant source of n for biological processes nitrogen saturation may therefore have substantial impacts on geochemical cycles involving both soil and water chemistry in order to determine the potential for the rocks and soils of karkevagge to be significant sources of n samples of the principal rock units of the valley along with soil developed on a variety of rock types were sampled ammonia ammonium contents were determined using ion chromatography ammonia ammonium contents of the sampled rock materials display a wide range of abundances with marble containing a mean nh4 abundance of 4300 mg n kg quartz schist 1600 mg n kg biotite schist 4300 mg n kg and garnet mica schist 4500 mg n kg soil ammonia ammonium abundances were found to be 1600 mg n kg n pool abundances range from 2 5 kg m3 for marble to 8 7 for garnet mica schist soil n pools were found to be 3 0 kg m3 the inorganic n present as ammonia ammonium measured in bedrock represents substantial n input into the geochemical budget the n in bedrock originates from organically bound nitrogen associated with sediment or geothermal waters representing a mixture of sedimentary mantle and meteoric sources nitrogen in the soil originates from the weathering of n rich rocks the presence of unweathered nitrate minerals or fluid inclusions released to the soil and ultimately to plants by assimilation by biota or nitrification geologic nitrogen in karkevagge rocks and soils may represent a large and reactive pool with the potential for considerable impact on the geochemical system to investigate the potential responses of nitrogen release as well as other nutrients to increasing co2 concentration scenarios flow through leaching experiments were conducted on crushed rock samples and soils from the study area leaching experiments revealed two to three fold increases in both n and k release with a tripling of carbon dioxide concentrations ammonium shows more rapid release than potassium which suggests substantial changes in nitrogen cycling with increasing co2 enrichment of the atmosphere

chemical weathering of monsoonal eastern china implications from major elements of topsoil major element compositions of 36 bulk samples and 41 clay samples which were obtained from 47 topsoils collected in monsoonal eastern china were investigated with conventional wet chemistry and x ray fluorescence xrf spectrometry respectively based on major element analyses the mobility of major elements and latitudinal distributions of sio2 al2o3 ratio chemical index of alteration cia chemical index of weathering ciw and weathering index of parker wip were analyzed meanwhile the suitability of these chemical weathering indices to topsoils in monsoonal eastern china and its controls were discussed these investigations indicate that na k ca mg and si are relatively depleted while mn p fe and ti are relatively enriched in topsoils of the study area by comparison with their contents in the upper continent crust ucc and that alkali metal na k and alkaline earth metal ca mg elements are generally easier to be depleted from their parent materials than other major elements during chemical weathering the latitudinal distributions of cia ciw and wip show that they are suitable to both bulk and clay samples but sio2 al2o3 is only suitable to clay samples not suitable in bulk ones all these investigations indicate a significant dependence of grain size in major element abundance and latitudinal distributions of sio2 al2o3 cia ciw and wip but parent rock type has little effect on them except its impact on the latitudinal distribution of wip in clay samples the significant grain size dependence probably indicates the presence of unaltered minerals in bulk samples thus we suggest that clay samples are more suitable to investigating chemical weathering of sediments on continents than bulk samples the trivial effect of parent rock type probably indicates a relatively uniform chemical weathering on various parent rocks correlation analyses indicate that climate is the dominant control of chemical weathering of topsoils in the study area and the significant latitude effect indicated by the spatial distributions of chemical weathering indices actually reflect the climate control on chemical weathering of topsoils chemical weathering indices actually reflect the integrated weathering history in the study area besides the dominant control of climate other factors like tectonics parent rock biology landform and soil depth and age might also have some effect on the chemical weathering of topsoils in the study area which needs further research c 2013 elsevier ltd all rights reserved

a granulometry and secondary mineral fingerprint of chemical weathering in periglacial landscapes and its application to blockfield origins abstract a review of published literature was undertaken to determine if there was a fingerprint of chemical weathering in regoliths subjected to periglacial conditions during their formation if present this fingerprint would be applied to the question of when blockfields in periglacial landscapes were initiated these blocky diamicts are usually considered to represent remnants of regoliths that were chemically weathered under a warm neogene climate and therefore indicate surfaces that have undergone only a few metres to a few 10s of metres of erosion during the quaternary based on a comparison of clay and silt abundances and secondary mineral assemblages from blockfields other regoliths in periglacial settings and regoliths from non periglacial settings a fingerprint of chemical weathering in periglacial landscapes was identified a mobile regolith origin under at least seasonal periglacial conditions is indicated where clay 0 5 silt 8 across a sample batch this contrasts with a mobile regolith origin under non periglacial conditions which is indicated where clay 0 5 silt 6 across a sample batch with clay 0 5 silt 8 in at least one sample a range of secondary minerals which frequently includes interstratified minerals and indicates high local variability in leaching conditions is also commonly present in regoliths exposed to periglacial conditions during their formation clay silt ratios display a threshold response to temperature related to the freezing point of water but there is little response to precipitation or regolith residence time lithology controls clay and silt abundances which increase from felsic through intermediate to mafic compositions but does not control clay silt ratios use of a sedigraph or coulter counter to determine regolith granulometry systematically indicates lower clay abundances and intra site variability than use of a pipette or hydrometer in contrast to clay silt ratios secondary mineral assemblages vary according to regolith residence time temperature and or precipitation a microsystems model is invoked as a conceptual framework in which to interpret the concurrent formation of the observed secondary mineral ranges according to the fingerprint of chemical weathering in periglacial landscapes there is generally no evidence of blockfield origins under warm neogene climates nearly all blockfields appear to be a product of quaternary physical and chemical weathering a more dominant role for periglacial processes in further bevelling elevated low relief non glacial surface remnants in otherwise glacially eroded landscapes is therefore indicated

frozen bed fennoscandian and laurentide ice sheets during the last glacial maximum the areal extents of the laurentide and fennoscandian ice sheets during the last glacial maximum about 20 000 years ago are well known1 but thickness estimates range widely from high domed2 to thin3 with large implications for our reconstruction of the climate system regarding for example northern hemisphere atmospheric circulation and global sea levels this uncertainty stems from difficulties in determining the basal temperatures of the ice sheets and the shear strength of subglacial materials4 a knowledge of which would better constrain reconstructions of ice sheet thickness here we show that in the absence of direct data the occurrence of ribbed moraines in modern landscapes can be used to determine the former spatial distribution of frozen and thawed bed conditions we argue that ribbed moraines were formed by brittle fracture of subglacial sediments induced by the excessive stress at the boundary between frozen and thawed bed conditions resulting from the across boundary difference in basal ice velocity maps of glacial landforms from aerial photographs of canada and scandinavia reveal a concentration of ribbed moraines around the ice sheet retreat centres of quebec keewatin newfoundland and west central fennoscandia together with the evidence from relict landscapes that mark glacial areas with frozen bed conditions the distribution of ribbed moraines on both continents suggest that a large area of the laurentide and fennoscandian ice sheets was frozen based and therefore high domed and stable during the last glacial maximum

parent material and chemical weathering in alpine soils on mt mansfield vermont usa we compared the elemental composition of soil and bedrock samples to determine the extent of chemical weathering and the nature of the soil parent material in alpine soils on vermont s highest summit previously it was unclear whether these soils formed through weathering of bedrock glacial till or eolian sediment or solely through the accumulation of organic matter in eighteen profiles no evidence was found to indicate that soils have developed in glacial till despite evidence that the mountain was completely inundated by the laurentide ice sheet in contrast results strongly support the theory that pedogenesis in this environment involves in situ bedrock weathering under a thickening blanket of acidic organic litter weathering indices reveal an increase in weathering intensity upwards from the bedrock and trends of normalized rare earth elements demonstrate a strong similarity between bedrock and soil samples leaching has concentrated less mobile elements such as al cr la p pb and ti in soil horizons and removed mobile elements such as co fe k mg mn si and zn x ray diffraction reveals that chlorite which is present in all bedrock samples and some saprolites has weathered completely from upper soil horizons and that hydrobiotite vermiculite kaolinite gibbsite and goethite have formed in the soil ratios of immobile elements ce cr nb ta ti y and zr in soil and bedrock samples are however notably different furthermore the moderately mobile trace elements cu mo and sr are actually more abundant in soil than in bedrock and soil concentrations of zr are up to an order of magnitude greater than in bedrock samples together these data argue for at least a modest eolian influx which may have arrived during the regression of lake vermont during the latest pleistocene or from an outwash source in the immediate post glacial period similarly increased ca and na concentrations in soil samples may signify modern deposition of dust bearing ca from agricultural fields and na from roads

blockfields old or new evidence and implications from some plateaus in northern norway evidence is presented from investigations on plateau top blockfields in still glaciated regions of north norway pits dug into these blockfields typically show profile depths 0 5 m and sometimes in excess of 1 m analysis of fines shows enrichment in the silt and clay sized fraction suggestive of prolonged chemical weathering chemical alteration of parent material is supported by xrd analysis which identifies a number of clay minerals present in blockfield samples a chemical weathering origin suggests that these plateau top blockfields are features which have considerable longevity in the landscape and have been forming since perhaps tertiary times the original weathering profiles have been destroyed by frost heaving mechanisms protection of the blockfield by cold based ice occurred during periods of glacial coverage

clay mineralogy chemical weathering and landscape evolution in arctic alpine sweden abstract the purpose of this research was to 1 characterize the clay mineralogy of soils in and adjacent to karkevagge a recently deglaciated valley in arctic sweden 2 document chemical weathering in a periglacial environment and 3 use the mineralogy to help explain landscape evolution soil samples were analyzed from 11 sites that differ in elevation parent material drainage slope and vegetation parent materials include residuum alluvium colluvium and glaciofluvial material derived from garnet mica schist plus in one locality a till of granitic origin x ray diffraction xrd was used to characterize the clay size fraction

geochemistry and mineralogy of saprolite in finnish lapland abstract an ancient saprolite has developed on the palaeoproterozoic granulite granite gneiss and amphibolite bedrock of the vuotso tankavaara area of central finnish lapland the present day climatic regime in finnish lapland lies within the northern boreal zone and so the saprolite there can be regarded as fossil cores of saprolite were collected from 4 sections 42 samples and analyzed chemically and mineralogically in the study area progressive weathering of the rocks has been marked by gradual enrichment in al fe and ti and depletion of na k and ca the higher concentration of fe iii and water and reduced na and ca in weathered bedrock in the 4 sections are indicative of oxidation hydration and leaching processes involved during weathering the primary minerals in the saprolite are plagioclase feldspar k feldspar quartz garnet almandine and hornblende the common secondary minerals are kaolinite halloysite and vermiculite in addition to minor amounts of sericite intense weathering is indicated by 1 the presence of kaolinite and halloysite in 4 sections of different bedrock types and 2 the comparatively lower sio2 al2o3 wt ratio 2 30 of weathered granulites 3 sections as compared to fresh granulite 4 33 and that of weathered amphibolite 2 68 as compared to fresh amphibolite 3 56 in general kaolinite and halloysite have formed through the weathering of feldspars garnet and biotite vermiculite is the most probable alteration product of biotite the formation of kaolinite and halloysite in finnish lapland indicates wetter and warmer climatic conditions during the time of their formation than at present the possible time for formation of the saprolite is early cretaceous early tertiary into middle miocene

underground structure and magmatic activity of izu oshima volcano japan as inferred from seismic reflection survey abstract a seismic reflection survey using the vibroseis trademark of continental oil co method was carried out on izu oshima volcano fifteen months after the eruption of november 1986 the survey line of about 10 km in length traverses the northern part of the volcano from east to west and intersects the fissure eruption craters which were formed by the 1986 eruption although the measurement condition was not excellent due to thick layers of unconsolidated volcanic products we obtained a good profile reaching to a depth of about 3 km below the main results obtained are summarized as follows 1 a remarkable reflector exists at a depth of 300 500 m below the surface which corresponds to the upper boundary of the neogene system forming the basement of the izu oshima volcano 2 the reflector is broken beneath the lateral volcanoes of past eruptions indicating ascent routes of magma 3 a remarkable fragmentation of reflectors in the basement is observed beneath the central part of the volcano which indicates repeated intrusion of magma into the basement 4 a low velocity zone is found at a depth of 2 4 km in the basement which most probably indicates the magma reservoir of the 1986 eruption although deeper structure was not well resolved these results demonstrate that the vibroseis method is quite effective for revealing the underground structure of a volcano

the poisonous rocks of karkevagge abstract the black schist in karkevagge swedish lapland has been reported to weather easily and produce a poisonous effect on vegetation this research was an investigation of that phenomenon as part of a larger study of weathering in karkevagge in july 1999 soil and plant samples were collected downslope of a poisonous boulder samples from the adjacent unaffected slope served as references biomass plant elemental composition and soil fertility were determined most plants within 1 4 m downslope of the poison boulder were dead and effects on plant growth could be seen to about 6 m plants near the boulder had elevated levels of k b al cd se and fe and lower levels of ca mn and ba compared to reference plants in the soil near the poison boulder extractable s cd and fe and salt contents were greater while ph and extractable cl p ca mg k ba ni and cr were lower than in the reference soil at 10 m downslope of the boulder soil and plant chemistry was more similar to the reference materials but some effects were still noted elemental analyses of the poison boulder and soil revealed no particular plant toxins although contents of fe and s were higher and ca lower than in reference materials we believe the poison is sulfuric acid which forms as a consequence of pyrite oxidation the dark color of the boulder is consistent with a pyrite bearing lithology and other field observations and laboratory analyses support the hypothesis coatings on local rocks include jarosite gypsum and copiapite secondary minerals associated with pyrite oxidation and weathering accelerated by sulfuric acid radiocarbon dating indicates that the rock fell off the cliff some time before 245 14 c years bp

preglacial surface remnants and quaternary glacial regimes in northwestern sweden abstract we present a detailed map of the distribution of preglacial surface remnants in the kebnekaise region of northwestern sweden in this mountain area we discern four important large scale geomorphological units each representing a specific set of erosional agents and formative conditions these are i intact preglacial surface remnants characterized by gentle slopes round summits wide shallow valleys and an absence of rock basins ii preglacial surface remnants showing signs of minor glacial erosion and deposition iii glacially scoured surfaces including glacial troughs iv deep fluvial valleys cut into the preglacial surface the pattern of glacial erosion is explained as the result of three specific modes of glaciation known to have existed during the last 120 000 years and inferred to have repeatedly prevailed during the last 2 75 million years cirque glaciation mountain ice sheets and fennoscandian ice sheets a deep ocean oxygen isotope record of foraminifera from the north atlantic dsdp 607 was used to infer the temporal extent of these modes of glaciation during the last 2 75 million years we interpret the preglacial landscape preservation and the pattern of glacial erosion in terms of the configuration the basal thermal regime and the duration of such glaciation events the average subglacial thermal regime of both ice sheet types was frozen on the uplands and melting in the main valleys where outlet glaciers and ice streams formed the pre glacial landscape is best preserved at intermediate elevations low enough not to have been covered by cirque glaciers and apparently high enough not to have experienced melted bed conditions and subglacial erosion during ice sheet overriding events in a narrow high relief zone along the elevation axis interglacial fluvial erosion was morphologically important the absence of glacial erosion on uplands in this zone allowed fluvial erosion to commence on the same locations during each ice free interval in contrast no persistent fluvial valley pattern could develop in zones subjected to repeated glacial scouring and hence derangement of fluvial patterns

mineralized breccia clasts a window into hidden porphyry type mineralization underlying the epithermal polymetallic deposit of cerro de pasco peru cerro de pasco peru is known for its large epithermal polymetallic zn pb ag cu bi mineralization emplaced at shallow level a few hundred meters below the paleo surface at the border of a large diatreme dome complex porphyry style veins crosscutting hornfels and magmatic rock clasts are found in the diatreme breccia and in quartz monzonite porphyry dikes such mineralized veins in clasts allow investigation of high temperature porphyry style mineralization developed in the deep portions of magmatic hydrothermal systems quartz in porphyry style veins contains silicate melt inclusions as well as fluid and solid mineral inclusions two types of high temperature 600 c quartz molybdenite chalcopyrite pyrite veins are found in the clasts early thin 1 2 mm and sinuous ht1 veins are crosscut by slightly thicker up to 2 cm and more regular ht2 veins the ht1 vein quartz hosts co2 and sulfur rich high density vapor inclusions two subtypes of the ht1 veins have been defined based on the nature of mineral inclusions hosted in quartz i ht1bt veins with inclusions of k feldspar biotite rutile and minor titanite and ii ht1px veins with inclusions of actinolite augite titanite apatite and minor rutile using an emplacement depth of the veins of between 2 and 3 km 500 to 800 bar derived from the diatreme breccia architecture and the supposed erosion preceding the diatreme formation multiple mineral thermobarometers are applied the data indicate that ht1 veins were formed at temperatures 700 c ht2 veins host assemblages of polyphase brine inclusions generally coexisting with low density vapor rich inclusions trapped at temperatures around 600 c rhyolitic silicate melt inclusions found in both ht1 and ht2 veins represent melt droplets transported by the ascending hydrothermal fluids la icp ms analyses reveal a chemical evolution coherent with the crystallization of an evolved rhyolitic melt quartz from both ht1 and ht2 veins also contains secondary low temperature 300 c brine and aqueous fluid inclusions that record the cooling of the system both vein types are locally crosscut and or reopened by a pre diatreme polymetallic event consisting of pyrite sphalerite with chalcopyrite disease galena chalcopyrite tetrahedrite tennantite and minor quartz la icp ms analyses of mineral and high temperature fluid inclusions hosted in ht1 and ht2 veins and in situ secondary ion mass spectrometry oxygen isotope analyses of vein quartz indicate a magmatic signature for the mineralizing fluids with no major meteoric water input and allow reconstruction of the source and chemical evolution of fluids that formed these porphyry style veins as snapshots of the early and deep mineralizations at cerro de pasco this detailed study of the porphyry type mineralization hosted in clasts offers a unique opportunity to reconstruct the late magmatic and early hydrothermal evolutions of porphyry mineralization underlying the world class cerro de pasco epithermal polymetallic zn pb ag cu bi deposit

morphology and stratigraphy from several deglaciations in the transtrand mountains western sweden the transtrand mountains western sweden are characterised by an abundance of glaciofluvial meltwater channels crossing lateral channels and channel systems overprinted by fluting occur at several localities drainage channel systems from three older deglaciations are interpreted to have been preserved despite overriding by later ice sheets deep sections machine excavated into the summit surface of the hundfjallet mountain revealed the presence of two lower diamictons into which two older generations of lateral channels were cut and subsequently buried by a late weichselian basal till buried frost sorted structures and frost fractured bedrock below the lowermost till indicate the repeated occurrence of periglacial condil conditions an organic layer between the two older units yielded an infinite radiocarbon age of 45000 yr bp the pollen content of this layer indicates a local mountain heath flora dominated by ericaceous dwarf shrubs and graminids the climate phase is interstadial or the beginning or end of an interglacial the different diamictons also display different pollen spectra during the last deglaciation the ice flow was from the north northeast the second youngest system of drainage channels corresponds to ice flow from approximately west northwest there are still older traces of separate deglaciation events from the east and north a frozen bed is interpreted to have been the standard basal regime for the last ice sheets to cover the transtrand mountains

preservation of landforms under ice sheets and ice caps abstract this article addresses the question of whether or not distinct glacial and non glacial landforms can survive beneath ice sheets and ice caps with little or no morphological alteration a review of recent work documents the existence of pre last stadial landforms and landscapes in areas covered by the fennoscandian and laurentide ice sheets a substantial number of independent works indicate that landforms such as eskers drainage channels and boulder fields have escaped destruction despite complete ice overriding during several tens of millenia full preservation of former ground surfaces or delicate landforms probably is linked to areas where the ice sheet base was continuously frozen to its bed larger robust landforms such as large drumlins appear to have been preserved even under wet based conditions in glaciated areas patches preserved under dry cold based conditions provide important windows towards the past showing landscapes that were destroyed in surrounding areas affected by wet based and eroding ice some consequences for the research fields of non glacial geomorphology archaeology and botany include the possibility of subglacial museums and refugia a time space model describes geomorphological access to information from older events in glaciated areas

ten years 1994 2004 of potential weathering in karkevagge swedish lapland this paper reports the findings of a ten year study of potential weathering of machine polished dolomite granite and limestone discs buried in shallow pits beneath a variety of vegetation cover types in karkevagge and on an adjoining ridge in swedish lapland the paper extends a previously published five year 1994 1999 record by adding the period 1999 2004 comparing the two periods and integrating results to provide a decadal record the field and laboratory procedures of the first period were faithfully replicated during the second period with the notable modification that only a segment of each original disc was replaced in the field for the second portion of the study a total of 48 dolomite 36 granite and 19 limestone discs were buried at shallow depths 60 cm beneath alpine tundra birch forest dryas heath heath meadow solifluction meadow and willow cover types with the exception of the willow which had only two each cover type had three replicated pits relationships identified during period 1 were generally repeated during period 2 salient results are the expected weathering rate order of limestone dolomite granite and statistically distinguishable differences in weathering rate by vegetation cover type differentiation of the two heath categories from the other vegetation cover types is the most important spatial distinction in weathering rate statistical distinctions among other measures were variable with soil horizon and burial depth being non significant ph variability being weakly distinguishable and drainage variability being important granite mass losses were generally too low to be useful for statistical separation dolomite discs experienced a statically higher loss rate during period 2 which had both a warmer and wetter air climate than period 1 minimum and maximum total decadal percentage losses from the discs were 0 2 and 25 7 for dolomite 0 07 and 0 57 for granite and 0 2 and 32 1 for limestone in general dolomite was the most useful material for monitoring mass loss with limestone weathering tending to be too rapid and granite weathering being too slow copyright 2006 john wiley sons ltd

chemical weathering in glacial environments do glaciers enhance or inhibit chemical weathering rates relative to other environments the importance of glaciers in the global carbon cycle and climate change hinges on the answer we show that catchments occupied by active alpine glaciers yield cation denudation rates greater than the global mean rate but do not exceed rates in nonglacial catchments with similar water discharge silica denudation rates are distinctly lower in glacier covered catchments than in their nonglacial counterparts because sediment yields are high from glaciers this suggests that water flux rather than physical erosion exerts the primary control on chemical erosion by glaciers potassium and calcium concentrations are high relative to other cations in glacial water probably due to dissolution of soluble trace phases such as carbonates exposed by comminution and cation leaching from biotite preferential weathering of biotite may result in higher 87 sr 86 sr in glacial runoff than expected from whole rock compositions thus although glaciers do not influence total chemical denudation rates at a given runoff they may yield compositionally distinctive chemical fluxes to the oceans disruption of mineral lattices by grinding increases dissolution rates this and high surface area should make glacial sediments exceptionally weatherable weathering of glacial erosion products in environments beyond the glacier margin deserves attention because it may figure prominently in global chemical cycles

soil formation and weathering in a permafrost environment of the swiss alps a multi parameter and non steady state approach spatially discontinuous permafrost conditions frequently occur in the european alps how soils under such conditions have evolved and how they may react to climate warming is largely unknown this study focuses on the comparison of nearby soils that are characterised by the presence or absence of permafrost active layer thickness 2 3 m in the alpine tundra and subalpine forest range of the eastern swiss alps using a multi method geochemical and mineralogical approach moreover a new non steady state concept was applied to determine rates of chemical weathering soil erosion soil formation soil denudation and soil production long term chemical weathering rates soil formation and erosion rates were assessed by using immobile elements fine earth stocks and meteoric 10be in addition the weathering index k ca ti the amount of fe and al oxyhydroxides and clay minerals characteristics were considered all methods indicated that the differences between permafrost affected and non permafrost affected soils were small furthermore the soils did not uniformly differ in their weathering behaviour a tendency towards less intense weathering in soils that were affected by permafrost was noted at most sites weathering rates the proportion of oxyhydroxides and the weathering stage of clay minerals were lower in permafrost soils in part erosion rates were higher at the permafrost sites and accounted for 79 97 of the denudation rates in general soil formation rates 8 8 86 7 t km2 y were in the expected range for alpine soils independent of permafrost conditions it seems that the local microenvironment particularly vegetation and subsequently soil organic matter has strongly influenced denudation rates as the climate has varied since the beginning of soil evolution the conditions for soil formation and weathering were not stable over time soil evolution in high alpine settings is complex owing to among others spatio temporal variations of permafrost conditions and thus climate this makes predictions of future behaviour very difficult this article is protected by copyright all rights reserved

the chemical weathering regime of karkevagge arctic alpine sweden abstract karkevagge is a valley located in swedish lapland at approximately 68 n and represents an arctic alpine landscape it is a presently periglacial glaciated trough incised into essentially horizontal metamorphic rocks some of which are presumably pyrite rich a set of coordinated studies was undertaken to investigate the nature of chemical weathering and pedogenesis in the valley and upon the abutting ridges august 1996 water quality measures reveal considerable spatial variation in solute totals with the highest total dissolved solute abundances being correlated with high sulfate abundances ridge crest soils exhibited poor horizonation but more extensive development of secondary clay minerals developed in situ than was found in valley flank and valley bottom soils valley soils exhibited multiple thin horizons many of which were buried and are taken to reflect great paraglacial and periglacial instability favorable microenvironments in the valley permit significant development of spodosols coarse debris along and across the valley bears both weathering rinds and rock coatings rock coatings in the valley include several types of iron films sulfate crusts carbonate skins and heavy metal skins karkevagge represents a mild arctic environment which does not preclude substantial chemical weathering in locations where abundant pyrite rich bedrock and water coincide this weathering follows pathways which are eminently expectable given that weathering of the pyrite rich rock permits generation of sulfuric acid which in turn weathers muscovite mica and calcite in local schists and marble respectively zones of intense chemical weathering also generate clearly visible deposits of gypsum and iron sulfate deposits such as jarosite not all arctic and or alpine environments are likely to be so active chemically but the results from karkevagge clearly show that dismissal of chemical weathering in cold regions on the basis of presumed first principles is erroneous consequently chemical weathering in such environments merits substantially more attention than it has hitherto received

variations in weathering processes and rates with time in a chronosequence of soils from glen feshie scotland chemical and mineralogical characteristics have been determined for a chronosequence of six soil profiles ranging in age from 80 13 000 years bp developed on river terraces in the western cairngorms of scotland the c horizons are similar chemically and mineralogically and the soils have similar pedogenetic histories exchangeable ca and mg decrease with time and base saturation decreases exponentially from 24 6 in the ah horizon of the youngest profile to 2 8 in the comparable horizon of the 10 000 year old profile according to the chronofunction y 3 372 22 612 exp 0 0007365t long term weathering rates of base cations calculated from the loss of these cations relative to zr appear to decrease exponentially with time but this may be due to the method of calculation the magnitude of loss of base cations decreases in the sequence na k mg ca but when the relative mobilities of these elements are considered the loss is in the order mg na ca k this reflects the dissolution of chlorite and loss of mg and the more rapid weathering of plagioclase feldspar and loss of na and ca particularly in the coarse sand fraction than k feldspar the clay fractions although 2 of all horizons also show distinct patterns with age in that chlorite and mica are less abundant in older soils and vermiculite is more abundant the latter phase often having hydroxyaluminium polymers in the interlayer region the chemical and mineralogical trends in the soil sequence are closely associated and are induced by pedogenic weathering

weathering implications of water chemistry in an arctic alpine environment northern sweden this paper reports on some of the chemical characteristics of late melt season water from karkevagge valley of the boulders above the arctic circle in northern sweden included in the analyses were temperature electrical conductivity ph so4 no3 k sio2 mg mn na fe and al these were measured in rain late lying snow and water from the major stream and lake as well as from pond tributary and seep sources in the valley a total of 71 samples was collected at 57 sites between august 6 and august 23 1996 for the purpose of characterizing the present weathering regime within this classic u shaped glacial valley evidence of chemical weathering included increases in solute concentrations over precipitation inputs and a source related wide variation in water chemistry the dominant anion measured in surface water was so4 that along with the presence of caso4 coatings on streambeds indicates that pyrite oxidation may contribute to the weathering regime high so4 concentrations were associated with gypsum coated streambeds and seeps that emerge from the bedrock low so4 concentrations were associated with tributaries flowing primarily on fresh rock and originating from melting snow estimated chemical denudation rate for the valley corrected for atmospheric inputs was 19 2 tons km2 yr although this is lower than previously reported our research supports earlier work indicating that chemical weathering is a major component of mass wasting in this arctic alpine environment

weathering rates of buried machine polished rock disks karkevagge swedish lapland some 48 dolomite 37 granite and 19 limestone machine polished disks were buried at soil horizon boundaries in 16 soil pits to maximum depths of 0 5 0 6 m within karkevagge a presently periglacial glaciated trough in arctic sweden the objective of the ongoing study is to determine near surface potential weathering rates beneath birch forest dryas heath heath meadow solifluction meadow and willow vegetation cover types selected disks were excavated after 1 year and all disks were excavated after 4 or 5 years the limestone disks weathered fastest followed closely by the dolomite disks but the granite disks weathered at much slower rates mean annual percentage mass loss over 4 or 5 years was 0 473 0 145 two standard errors for dolomite disks 0 032 0 005 two standard errors for granite disks and 1 104 0 446 two standard errors for limestone disks for dolomite disks the dryas heath and heath environments weathered the most slowly a trend that was generally followed by the granite disks poor drainage i e increasing wetness and decreasing ph were found to promote dolomite weathering rates in a statistically significant manner surficial and subsurface weathering rates at individual sites were generally found to be correlated for dolomite but not granite copyright 2002 john wiley sons ltd