geochemical identification of episodes of gold mineralisation in the barberton greenstone belt south africa abstract the morphology and mineral chemistry of gold and associated sulphides at sheba fairview and new consort gold mines in the barberton greenstone belt bgb identify two main types of mineralization the first type occurs associated with sulphides mainly pyrite either as inclusions 10 30 m or as sub microscopic gold the second gold type consists of large gold grains 100 m within the silicates mostly quartz la icp ms studies reveal that some gold and associated sulphide grains contain high values of cl br na and i the elemental relationships reflect the different chemistry and precipitation processes of possible source fluids and identify several episodes of mineralisation in the study area one of them formed due to a boiling process in a supercritical hydrothermal environment this paper reports on the compositional characteristics of these gold grains the significance of the halogen contents and the implications for possible sources of the gold and associated sulphides

micromorphology of a welded sangamonian to wisconsinan age paleosol in southwestern wisconsin abstract micromorphological characteristics indicate that in southwestern wisconsin pedogenesis transgressed the sangamonian wisconsinan chronostratigraphic boundary in conjunction with colluvial and eolian sedimentation the use of micromorphology helps to distinguish between pedological colluvial and eolian components in the paleosol horizon sequence which can be difficult to resolve and interpret solely from field investigations and from other laboratory analyses results show that a basal loess mixed zone within the welded paleosol profile contains features that are the products of colluvial reworking processes we present micromorphology data which support stratigraphic relationships suggesting that colluvial processes were important in the formation of basal loess mixed zones in addition to other possible mixing processes such as pedoturbation and bioturbation

formation age and metamorphic history of the nuvvuagittuq greenstone belt abstract the nuvvuagittuq greenstone belt ngb in northern quebec canada is dominated by mafic and ultramafic rocks metamorphosed to at least upper amphibolite facies rare felsic intrusive rocks provide zircon ages of up to 3 8 ga david et al 2009 cates and mojzsis 2007 establishing the minimum formation age of the ngb as eoarchean primary u rich minerals that may provide reliable formation ages for the dominant mafic lithology called the ujaraaluk unit have yet to be found metamorphic zircons rutiles and monazites are present in the unit and give variably discordant results with 207pb 206pb ages ranging from 2 8 ga to 2 5 ga the younger ages overlap 2686 4 ma zircon ages for intruding pegmatites david et al 2009 and sm nd ages for garnet formation in the ujaraaluk rocks suggesting this era as the time of peak metamorphism and metasomatism in the ngb coeval with regional metamorphism of the superior craton sm nd data for ujaraaluk whole rocks scatter about a sm nd vs 143nd 144nd correlation mswd 134 whose slope would correspond to 3 6 0 2 ga if interpreted as an isochron this isochron is seen to consist of a series of younger 3 2 2 5 ga slopes for the different geochemical groups within the ujaraaluk emanating from a baseline distribution older than 4 ga the 146sm 142nd chronometer is less affected by metamorphism at 2 7 ga because of 146sm extinction prior to 4 ga expansion of the 142nd dataset for the ujaraaluk and associated ultramafic rocks continues to show a good correlation between sm nd ratio and 142nd 144nd that corresponds to an age of 4388 15 17 ma the dataset now includes samples with superchondritic sm nd ratios that extend the correlation to 142nd excesses of up to 8 ppm compared to the terrestrial standard with a total range in 142nd 144nd of 26 ppm the upper sm nd ratio end of the ujaraaluk correlation is defined by rocks that are interpreted to be cumulates to compositionally related extrusive rocks indicating that this crystal fractionation had to occur while 146sm decay was active i e well before 4 ga intruding gabbros give 143nd and 142nd isochron ages of respectively 4115 100 ma and 4313 41 69 ma also supporting an hadean age for the gabbros and providing a minimum age for the intruded ujaraaluk unit 3 6 ga tonalites surrounding the ngb 3 8 ga trondhjemitic intrusive veins and a 2 7 ga pegmatite show a deficit in 142nd compared to the terrestrial standard these felsic rocks plot to the low sm nd ratio side of the ujaraaluk isochron and do not show a correlation between their sm nd and 142nd 144nd ratios which can be explained if they are melts of ancient lree enriched mafic rocks such as the ujaraaluk with the melting occurring after 146sm was extinct a subset of least disturbed ujaraaluk samples has coherent isotopic compositions for both short lived and long lived nd isotopic systems giving 143nd and 142nd isochron ages overlapping within error of 4321 160 ma mswd 6 3 and 4406 14 17 ma mswd 1 0 respectively this age represents our best age estimate for the ujaraaluk unit the ngb thus preserves over 1 6 billion years of early earth history including an expanse of mafic crust formed in the hadean

macrostructure of diagnostic b horizons relative to underlying bc and c horizons in podzols luvisol cambisol and arenosol evaluated by image analysis abstract five soils albic ortsteinic podzol albic podzol and dystric brunic arenosol developed from sand and haplic luvisol and eutric cambisol developed from loess were studied to evaluate morphometric features and selected physico chemical properties of b horizons in relation to bc and c horizons by standard laboratory methods soil texture total organic carbon the amount of carbonates ph particle and bulk density total porosity were measured samples with preserved structure were used to produce for each tested layer 16 resin impregnated 8 9 cm in size opaque soil blocks for qualitative and quantitative soil structure analysis utilizing the scanned images of the opaque blocks the following morphometric parameters were measured the relative area of pore cross section macroporosity the relative length of pore cross sections perimeter the relative number of pore and solid phase element cross sections the mean area of pore and solid phase element cross section and fraction of number of horizontally diagonally and vertically oriented pore cross sections the numerical characteristics of each soil structure revealed that the layers of the b horizons differed from the underlying layers representing bc c and ck horizons in an ambiguous way depending on soil genesis the obtained morphometric parameters and morphological analysis showed that in the b horizons the original structure of sand or loess obliterated due to the processes of enrichment of the b horizons in organic substances al and fe and the soil fauna and flora activity and consequently the development of aggregate structure or pores cutting the soil groundmass the morphometric parameters measured by image analysis corresponded logically with basic soil properties namely the organic carbon content and total porosity increased and the bulk density decreased while the morphometric parameters grew showing the development of more loose soil arrangement no characteristic differences in view of the measured morphometric parameters were found between bhs bs and bt horizons illuvial accumulation and bwo and bw horizons their genesis driven by in situ accumulation the bc horizons were much more similar than the b horizons to the parent material with respect to the values of morphometric parameters it should be stressed that the quantitative image analysis exposed visible in the opaque blocks qualitative dissimilarities between soil layers but due to the innate for soil especially a forest one high heterogeneity of structure the observed differences between the average values of morphometric parameters for the layers were not always validated through statistical tests the orientation analysis provided no characteristic description of soil structure status it helped however to interpret other morphometric parameters our study demonstrated that the quantitative macrostructure analysis could be an indirect method for evaluation of pedogenesis intensity because physico chemical properties of the developed b horizons controlled the occurrence and extent of abiotic and biotic factors regulating soil structure

using physical volcanology chemical stratigraphy and pyrite geochemistry for volcanogenic massive sulfide exploration an example from the blake river group abitibi greenstone belt an innovative approach to enhance volcanogenic massive sulfide vms exploration in regions outside of mining camps is to first use physical volcanology with litho and chemostratigraphy to establish the location of effusive centers in the volcanic units and use pyrite geochemistry in sulfide bearing stratified intervals with whole rock geochemistry in the underlying volcanic units to identify hydrothermal upflow zones this methodology is illustrated by this study in the archean blake river group within the abitibi greenstone belt of quebec and ontario the blake river group contains numerous vms deposits yet large segments remain underexplored including the hebecourt formation which contains four tholeiitic units that range from basalt to rhyolite in composition effusive centers are located for three felsic units and subunits 1 low ti porphyritic subunit of the main rhyolite 2 high ti aphyric subunit of the main rhyolite and 3 the upper rhyolite and for a basaltic andesite unit stringer and disseminated zn cu mineralization occurs within the flank breccia of the low ti rhyolite dome an inferred vent area for an overlying basaltic andesitic unit has also been identified in this area illustrating the coincidence of hydrothermal upflow zones with volcanic vents la icp ms analysis of pyrite grains from several sulfide bearing stratified intervals indicates two broad areas of higher cu zn au and ag contents the eastern region corresponds to known volcanic vents and mineralization the western region also indicates upflow of cu bearing hydrothermal fluids and corresponds to a possible effusive center for the high ti subunit the western region does not contain known mineralization at lower stratigraphic positions but it has not been thoroughly explored

comparative micromorphology of two late pleistocene paleosols in the paris basin summary the micromorphology of two late pleistocene paleosols in the paris basin st pierre les elbeuf and bois du moulin were studied in order to characterize their pedogenic and sedimentary processes and to reconstruct and interpret the pedosedimentary history and climate of each profile the micromorphological observations of greatest interpretive value were the types of clayey and silty textural accumulations argillans and siltans pedality and porosity of lesser value were papules bioactivity and concretions during the last interglacial period on both profiles developed a sol brun lessive comparable to those developed during the holocene with the onset of cold conditions of the last glaciation the two differentiate pedologically and sedimentologically at elbeuf in the seine valley we observe colluviation of silts and the development of grey forest soils with strong textural degradation under cold and moderately dry local conditions at moulin on the plateau the grey forest phase is very weak and probably brief and is followed by a marked phase of churning and eluviation of silt conditions were wetter than in the valley such that the upland position protected the profile from colluvial truncation the advantages of micromorphology in interpreting pedo sedimentary sequences is discussed

two distinct origins for archean greenstone belts abstract applying the th yb nb yb plot of pearce 2008 to the well studied archean greenstone sequences of western australia shows that individual volcanic sequences evolved through one of two distinct processes reflecting different modes of crust mantle interaction in the yilgarn craton the volcanic stratigraphy of the 2 99 2 71 ga youanmi terrane mainly evolved through processes leading to th yb nb yb trends with a narrow range of th nb constant th nb greenstones in contrast the 2 71 2 66 ga volcanic stratigraphy of the eastern goldfields superterrane evolved through processes leading to th yb nb yb trends showing a continuous range in th nb variable th nb greenstones greenstone sequences of the pilbara craton show a similar evolution with constant th nb greenstone evolution between 3 13 and 2 95 ga and variable th nb greenstone evolution between 3 49 and 3 23 ga and between 2 77 and 2 68 ga the variable th nb trends dominate greenstone sequences in australia and worldwide and are temporally associated with peaks in granite magmatism which promoted crustal preservation the increasing th nb in basalts correlates with decreasing end reflecting variable amounts of crustal assimilation during emplacement of mantle derived magmas these greenstones are typically accompanied in the early stages by komatiite and can probably be linked to mantle plume activity thus regions such as the eastern goldfields superterrane simply developed as plume related rifts over existing granite greenstone crust in this case the youanmi terrane their th nb trends are difficult to reconcile with modern style subduction processes the constant th nb trends may reflect derivation from a mantle source already with a high and constant th nb ratio this and a lithological association including boninite like lavas basalts and calc alkaline andesites all within a narrow th nb range resembles compositions typical of modern style subduction settings these greenstones are very rare and were probably only preserved when fortuitously stabilised by granitic magmatism related to the evolution of later variable th nb greenstones the rarity of constant th nb trends suggests that either processes forming them never dominated archean greenstone evolution or that such greenstones simply were rarely preserved metamorphic mobility of th renders the th yb nb yb plot inappropriate for interpreting eoarchean greenstone units worldwide nevertheless such sequences appear dominated by volcanic rocks that in modern settings reflect only the embryonic or initiation stages of subduction they probably record subduction failure rather than anything resembling modern style subduction

investigations on buried soils and colluvial layers around bronze age burial mounds at bornhoved northern germany an approach to test the hypothesis of landscape openness by the incidence of colluviation the idea of open landscapes around prehistoric burial mounds is founded on their topographical position and findings of plaggen clots within the hills at some sites we have investigated the surroundings of four bronze age burial mounds at bornhoved northern germany to test whether this assumed landscape openness enabled soil erosion and colluviation or not the soils and colluvia within a watershed below the burial mounds were investigated in six large exposures and additional auger cores the chronology is based on 21 ams radiocarbon dates complemented by charcoal analysis and the content of selected heavy metals in the sediments colluvia were deposited in the late neolithic 2500 2200 cal bc roman emperor times 250 400 cal ad mediaeval times ad 600 1400 and modern times ad 1800 2000 our findings indicate that the soil surfaces were protected against soil erosion during the phase of bronze age funeral use cal 1800 600 bc either the prehistoric gravediggers practised a well suited form of pasturing to keep the scenery open or the surroundings of the burial mounds were forested at the time of funeral use the results of charcoal analysis reflect the known succession of woody taxa in the region and underline the great potential of anthracology on colluvial layers for palaeoenvironmental reconstructions apart from traditional archives such as lakes or mires bulk radiocarbon dating of organic matter overestimated the time of burial of a buried soil as well as the time of deposition of colluvial layers considerably

pre 2 8 ga crust in the opatica gneiss belt a potential source of detrital zircons in the abitibi and pontiac subprovinces superior province canada ages of detrital zircons in post 2 7 ga metasedimentary rocks of the southern abitibi and northern pontiac subprovinces require that pre 2 8 ga crust was exposed during or following deformation of the 2 70 and 2 68 ga and the belt forms a high grade crystalline core to a south vergent mountain belt along the northern margin of the abitibi subprovince erosion of the opatica and northern abitibi during thrusting would shed detritus southward in advance of a south vergent thrust system the lac rodayer complex may be the enigmatic source of 2 8 ga detrital zircons within turbidites of the southern abitibi and northern pontiac subprovinces

human induced soil erosion and gully system development in the late holocene and future perspectives on landscape evolution the myjava hill land slovakia in humid climate zones like central europe past soil erosion and gullying are strongly connected with agricultural expansion and extreme soil erosion events often play an important role in land abandonment this paper provides a case study to demonstrate the interaction between land use soil erosion floodplain development and land use changes in a 0 order catchment in the babikovce catchment myjava hill land situated in western slovakia sedimentological pedological geoarchaeological and historical data indicate two main periods of intensive hillslope erosion and gullying since the high middle ages in particular a few extreme precipitation events or rapid snowmelts caused intensive runoff events and gullying on cleared land the formation of the gully system and fan deposits in the babikovce catchment and other areas also forced the occurrence of intensive muddy floods and caused floodplain aggradation and meander changes along rivers in the myjava hill land as a result the development of the dense network of permanent gullies in the myjava hill land can be associated with the transformation of woodland into farmland and later land abandonment today the area is highly truncated by soil erosion and very difficult to farm

extreme rainfall and flooding from orographic thunderstorms in the central appalachians 1 the central appalachian region has experienced some of the largest rainfall accumulations in the world at time intervals less than 6 h including the 18 july 1942 smethport pennsylvania storm that produced 780 mm in less than 5 h the envelope curve of central appalachian flood peaks at small drainage areas less than 1000 km2 is dominated by orographic thunderstorm systems like the smethport storm orographic thunderstorm systems that have produced catastrophic flooding in the central appalachians are examined through observational and numerical model analyses using the weather research and forecasting wrf model analyses suggest that the frequency of catastrophic flooding varies over the central appalachian region and that small scale variation may be linked to the role of complex terrain in altering thunderstorm dynamics catastrophic flooding along the western margin of the central appalachians is dominated by four storms that occurred on 18 19 july 1889 1942 1977 and 1996 which were associated with warm season extratropical systems and were characterized by rapidly moving storm elements in complex terrain along the eastern margin and interior of the central appalachians catastrophic flooding is linked to four terrain locked orographic convective systems that occurred 17 18 june 1949 18 19 august 1969 27 june 1995 and 11 august 2003 wrf model simulations of the little river storm june 1949 rapidan storm june 1995 smethport storm 18 july 1942 and redbank storm 18 19 july 1996 are used to characterize ingredients of catastrophic rainstorms in the central appalachians

lateglacial to holocene pedogenesis and formation of colluvial deposits in a loess landscape of central europe wetterau germany abstract loess areas in central europe have been settled since ancient times and are therefore predestined to archive information about both the paleoenvironment with and without human activities in gentle rolling loess landscapes distinct short and shallow valleys so called dells are prominent landscape elements that act as sediment traps the loess paleosol colluvium lpc sequence of gambach wetterau germany can be regarded as an exceptional sequence for lateglacial holocene pedogenesis and human impact in dry loess landscapes with the lpc sequence of gambach reflects climate controlled pedogenesis from ca 15 ka to 4 7 ka with the formation of a cambisol having some properties related to chernozem soil forming processes during the lateglacial a chernozem is developed in the deposits of the laacher see tephra which still show the influence of periglacial climate in their lowermost part the upper part of these deposits was relocated by colluvial processes at around 6 7 ka chernozem soil forming processes were still ongoing until 4 7 ka when these shifted to luvisol formation which is still active today since 4 7 ka extended land use with indications of agricultural fire use since at least 2 3 ka led to the formation of colluvial deposits combined with a topographic leveling of upland positions on a landscape scale the results of the formative element of humans on loess landscapes from the wetterau can also be taken as representative for around 9400 km2 of dry loess landscapes in central europe

contrasting patterns of hydrological changes in europe in response to holocene climate cooling phases the quantitative reconstruction of climatic parameters from pollen and lake level data obtained at saint jorioz lake annecy eastern france gives evidence for cooler and wetter conditions during the 8 2 ka cold event a comparison of these regional data with other hydrological records reconstructed in europe for the same period suggests as a working hypothesis that mid latitudes between ca 50 and 43 underwent wetter conditions in response to the cooling whereas northern and southern europe were marked by drier climate in the latter case leading to an interruption of the sapropel 1 formation in the mediterranean a similar hydrological tri partition of europe can be observed during other holocene cooling phases associated with north atlantic ird events data indicate that the middle zone characterised by wetter climate conditions could have had a more extended latitudinal amplitude during phases of climate cooling weaker than the 8 2 ka event the differences in expansion of the wet mid european zone depending on holocene climate cooling phases could reflect variations in the strength of the atlantic westerly jet in relation with the thermal gradient between high and low latitudes

a review of the superior province of the canadian shield a product of archean accretion abstract the superior province consists of northern and southern high grade gneiss subprovinces and a central region of alternating granite greenstone and metasedimentary belts subprovinces are commonly fault bounded and display contrasting lithological assemblages metamorphic and structural styles geophysical characteristics and ages they are comparable to phanerozoic suspect terranes the middle and late archean rocks of the superior province are of mantle and juvenile crustal origin with little evidence of inheritance of components older than ca 3 1 ga high grade gneiss subprovinces are mainly deeper level equivalents of the supracrustal rich belts but one minnesota river valley is part of an older ca 3 6 ga terrane that was juxtaposed late in the tectonic history granite greenstone terranes are characterized by low grade volcano sedimentary sequences tholeiitic komatiitic submarine lava plain tholeiitic calc alkalic submarine to subaerial central complexes early platform type quartz arenite stromatolitic carbonate late timiskaming type shoshonitic alkalic volcanic fluvial sediment that range in age from ca 3 0 ga to 2 7 ga the volcanics represent oceanic island arc and continental arc volcanism the quartz arenite carbonate sequences deposition on relatively stable early formed ca 3 0 ga crust and the timiskaming type sequences deposition in pull apart basins developed along strike slip faults late archean ca 2 75 2 70 ga greenstone sequences occur throughout the superior province middle archean ca 3 0 2 8 ga sequences are common in northern and central superior province rare or absent in the south volcanism was accompanied by mafic to trondhjemitic plutonism the metasedimentary belts consist of variably metamorphosed volcanogenic turbidites with detrital zircons ranging in age from ca 3 0 ga to 2 7 ga the metasediments were deposited after major volcanism and probably represent accretionary prisms late archean orogenesis accompanied and followed by calc alkalic plutonism youngs southward from about 2 73 2 72 ga to 2 70 2 68 ga it involved large scale north south compression and dextral transpression and displays thin to thick skinned transitions the contemporaneity of events along the lengths of the belts and their southward younging coupled with the evidence of major compression are consistent with subduction driven oblique accretion of oceanic and continental volcanic arcs accretionary sedimentary wedges older microcontinental fragments etc in a convergent margin setting analogous to parts of the pacific rim differences eg abundance of komatiites and tonalitic plutonic suites are attributable to a hotter archean mantle

pedological analysis as a key for reconstructing primary loess relief a case study from the magdalenian site in klementowice eastern poland abstract the subject of the study was a gentle and smooth loess slope featuring a magdalenian culture site located near the northern edge of the loess belt in eastern poland based on the probing of 130 soil profiles across a 10 10 m mesh within an area of 1 2 ha the land surface after the deposition of weichselian loess was reconstructed soil mapping indicated the patchwork character of the present soil cover which consists of luvisols of varying degrees of transformation resulting from agricultural use partly eroded and buried soils co occur in the upper part of the ridge flat non eroded soils in the middle part and eroded soils in the lower part in the archaeological site area with buried soils at the foot of the slope the thickness of the primary soil cover was reconstructed by means of geostatistical analyses this was used to reconstruct the primary undulating land relief characterised by numerous small convex forms small hillocks and hummocks and concave forms closed depressions and slope troughs these forms were levelled out by soil erosion in the course of agricultural use the planation of relief caused a decrease of the mean inclination by 25 and elevation difference by 13 the greatest changes occurred on the ridge flat where the denudation of small hillocks and the filling of closed depressions took place local inclinations decreased by up to fourfold and in some places the inversion of slope exposure occurred during the 210 years of agricultural use the eroded surfaces subsided by an average of 0 32 m and at most by 0 92 m which corresponds to an average of 1 5 mm and 4 3 mm per annum respectively less than 50 of the eroded soil material was deposited within the investigated slope most of the material was carried off beyond it the accumulated surface however is 2 5 times smaller than the eroded surface hence the accumulation indicators are slightly higher than the erosion indicators

holocene sediment dynamics in the environs of the fortification enclosure of cornesti iarcuri in the romanian banat abstract the presented study combines data from geomorphological geochemical sedimentological chronometric and archaeological records providing first insights into the holocene landscape development in the environs of the late bronze age fortification enclosure cornesti iarcuri this large scale archaeological site is located in a loess covered undulating landscape at the eastern edge of the great hungarian plain in western romania sediment archives from geomorphologically different locations closely related to the copper age to late bronze age settlements are presented mainly stable geomorphic conditions throughout the holocene occurred on the high plains of the vinga plain as indicated by chemical alteration of the loss deposits and soil formation processes exceeding 2 m in contrast two cores from an alluvial fan of a minor drainage system in direct vicinity of the archaeological site document varying morphodynamics throughout the holocene phases of geomorphic activity and stability are indicated by the formation of fan deposits and paleosols developed in these sediments 14 c dates from charcoal extracted from the fan sediments show maximum deposition ages between c 4400 cal bp and c 2900 cal bp thus the formation of the charcoal coincides with the copper age to late bronze age development of the settlement sites daub pieces incorporated into these reworked soil sediments provide evidence for human activities in the catchment this in turn may indicate that the erosion processes that led to the fan formation are linked to those activities however reworking and redeposition of the charcoal and daub bearing sediments due to retrogressive erosion during the last millennia cannot be excluded

holocene climate variability as reflected by mid european lake level fluctuations and its probable impact on prehistoric human settlements abstract a data set of 180 radiocarbon tree ring and archaeological dates obtained from sediment sequences of 26 lakes in the jura mountains the northern french pre alps and the swiss plateau was used to construct a holocene mid european lake level record the dates do not indicate a random distribution over the holocene but form clusters suggesting an alternation of lower and higher climatically driven lake level phases they provide evidence of a rather unstable holocene climate punctuated by 15 phases of higher lake level 11 250 11 050 10 300 10 000 9550 9150 8300 8050 7550 7250 6350 5900 5650 5200 4850 4800 4150 3950 3500 3100 2750 2350 1800 1700 1300 1100 750 650 cal bp and after 1394 ad a comparison of this mid european lake level record with the gisp2 polar circulation index pci record the north atlantic ice rafting debris ird events and the 14 c record suggests teleconnections in a complex cryosphere ocean atmosphere system correlations between the gisp2 pci the mid european lake level the north atlantic ird and the residual 14 c records suggest that changes in the solar activity played a major role in holocene climate oscillations over the north atlantic area

subduction influence of philippine sea plate on the mantle beneath northern kyushu sw japan an examination of boron contents in basaltic rocks abstract northern kyushu characterized by the subduction of two oceanic slabs a hot shikoku basin and a cold philippine sea plate beneath the eurasian plate forms a complex portion of southwestern japan arc in order to evaluate the effect of slab derived fluids from these two contrasting oceanic plates we determined the boron b contents in basaltic rocks from ten volcanoes and three old volcanic fields which erupted since 11 ma since b is distinctly concentrated into slab derived fluids among the earth s materials we attempted to estimate the influences of subduction on the sub arc mantle composition from the interpretation of the b data in basaltic rocks old 11 6 ma basaltic rocks contain low ratios of b sm 0 5 1 3 b zr 0 02 0 05 and b nb 0 2 0 5 suggesting little influence of subduction similarly backarc basaltic rocks occurring throughout the observed period show little influence of subduction in contrast volcanic products from young aso volcano located at the volcanic front show a strong influence of subduction as indicated by the high b sm 1 6 4 3 b zr 0 07 0 16 and b nb 1 4 3 7 ratios after 6 ma the volcanic arc segment containing aso volcano is associated with the subduction of the cold philippine sea plate hence a b rich fluid was probably added to the sub arc mantle however yufu tsurumi and kuju volcanoes which are located at the same volcanic front show small b sm 0 9 1 9 b zr 0 04 0 07 and b nb 0 5 0 9 ratios this implies that the subduction of the hot shikoku basin released fluids from the slab at shallow depths therefore it is depleted of b and other subduction components by the time it reaches the volcanic front

magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace element discriminant diagrams when dealing with ancient subalkaline volcanic rocks the alkali total iron magnesium afm diagram is of limited use in assigning a tholeiitic versus calc alkaline affinity because these eleme

high resolution gully erosion and sedimentation processes and land use changes since the bronze age and future trajectories in the kazimierz dolny area naleczow plateau se poland abstract this paper presents the results of 40 years of research on the gully system in the doly podmularskie catchment 0 35 km in size which is situated in the south western part of the loess covered naleczow plateau in se poland topographic stratigraphic and pedologic investigations and monitoring of a tributary gully gully area 0 7 ha catchment 2 5 ha were combined with historical archaeological and palaeoecological records the results reveal a long and complex history in terms of the temporal and spatial extent and the impact of land use on gully erosion and the long term feed back mechanisms between land use changes and natural processes since the end of the pleistocene phases of gully erosion and subsequent filling occurred in the bronze age and around the 10th to 11th centuries the most severe deepening and expansion of the gully took place in the 17th century the results also show that field structures and land use intensity had a significant influence on the frequency and magnitude of run off soil erosion piping and landslide events the last significant erosion phase started in the mid 19th century with renewed headward retreat and down cutting within older gully fills today most of the catchment is either forested or the land is covered in berry shrubs in the future the area will continue to produce sediments because of the steep slopes and because there are still areas of bare soil with a low resistance to erosion a legacy from past land uses which will remain a factor affecting soil erosion and sedimentation processes in the future this study is an example of how important it is to observe and understand slow geomorphologic processes and rare extreme events in the light of land use changes when investigating long term human environment interactions

estimating the upper tail of flood frequency distributions procedures for estimating recurrence intervals of extreme floods are developed estimation procedures proposed in this paper differ from standard procedures in that only the largest 10 20 of flood peaks are explicitly used to estimate flood quantiles quantile estimation procedures are developed for both annual peak and seasonal flood frequency distributions the underlying model of flood peaks is a marked point process where represents time of occurrence of the jth flood during year i and the mark represents magnitude of the flood peak results from extreme value theory are used to parameterize the upper tail of flood peak distributions quantile estimation procedures are applied to the 92 year record of flood peaks from the potomac river results suggest that potomac flood peaks are bounded above the estimated upper bound is only 20 larger than the flood of record

are mid latitude slopes sensitive to climatic oscillations implications from an early holocene sequence of slope deposits and buried soils from eastern germany abstract on a straight slope within the lake catchment of kleiner tornowsee brandenburg germany a sequence of slope sediments has been deposited during the late glacial the early holocene and around cal 4 2 ka before today 800 500 and 300 years ago the chronology is based on 21 radiocarbon dates and 11 osl dates and a deposition model including the numerical data as well as stratigraphic information has been calculated with oxcal 4 1 a comparison of the woody taxa of charcoal particles n 566 embedded within the sediments with the known regional vegetation history confirmed the reliability of the dates according to the age volume and distribution the deposition of the early holocene sediments at ca 10 3 kyrs ca 9 5 kyrs and ca 8 2 to 7 7 kyrs before today strongly suggests an influence of known climatic deteriorations phases on geomorphologic processes cold and dry climatic conditions probably promoted wildfires in pinus dominated forests and therefore triggered the observed repeated slope instability in consequence mid latitude slope deposits provide a potential to reconstruct the geomorphological response to climatic events at a high spatial resolution in contrast the recorded mid to late holocene soil erosion phases on the slope have been triggered by land use activities apart from traditional environmental archives slope deposits provide valuable information about the vegetation and climate history

trace element geochemistry and petrogenesis of felsic volcanic rocks associated with volcanogenic massive cu zn pb sulfide deposits volcanogenic massive cu zn pb sulfide vms deposits occur primarily in subaqueous rift related environments e g oceanic fore arc arc back arc continental margin or continental are hosted primarily by bimodal mafic felsic volcanic successions and are typically associated with felsic volcanic rocks with specific geochemical characteristics fi alkalic dacites and rhyodacites despite being abundant in the rock record are typically barren some fii calc alkalic rhyodacites and rhyolites host vms deposits but most are barren fiii tholeiitic and fiv depleted rhyolites and high silica rhyolites are much less abundant in the rock record but commonly host vms deposits regardless of age and fiii rhyolites appear to host the largest deposits most petrogenetic models proposed for the formation of fii and fiii fiv felsic volcanic rocks link felsic magma genesis to fractionation processes in high level magma chambers now represented by associated subvolcanic intrusions where the magma is also interpreted to have supplied the heat and or metals required to generate and sustain the vms forming convective hydrothermal system however the relatively constant compositions of fii and fiii fiv felsic volcanic rocks within individual areas the high eruptive temperatures at or above liquidus of fiii rhyolites and the bimodality of vms hosting volcanic successions indicate that fractional crystallization within subvolcanic intrusions could not have generated or significantly modified the compositions of fii and fiii fiv magmas this coupled with detailed geological geochemical and geochronological studies indicates that many of these subvolcanic intrusions were emplaced in multiple phases and that the later most voluminous phases often cut ore associated hydrothermally altered rocks a reassessment of the physical conditions responsible for producing the geochemistry of ore associated fii and fiii fiv felsic volcanic rocks and a review of the compositions of felsic volcanic rocks associated with vms deposits that range in age from mesoarchean to cenozoic provide important constraints on models for vms associated felsic volcanic rocks and their relationship to mineralization the compositions of felsic volcanic rocks may be explained by low to moderate degrees of partial melting of mafic sources at a range of depths within rift environments where the mineralogy and composition of the source regions modes and degrees of partial melting pressure and temperature of melting and to a lesser extent subsequent fractionation processes account for the compositional variations from fi through fii to fiii fiv long lived enhanced heat flow and structural permeability of rift environments that allows partial melting to form some fii rhyolites at midcrustal levels 10 15 km and fiii fiv rhyolites at shallow crustal levels 10 km both within the zone of brittle fracture permeability are essential to sustain the high temperature convective hydrothermal systems that are required to form large vms deposits and camps rift environments contain long lived thermal magmatic and structural corridors that focus magma ascent heat flow high temperature convective hydrothermal systems and emplacement of subvolcanic intrusions that are favorable environments for the formation of vms deposits and fii and fiii fiv felsic volcanic rocks

early holocene forest fires drift sands and usselo type paleosols in the laarder wasmeren area near hilversum the netherlands implications for the history of sand landscapes and the potential role of mesolithic land use abstract in the laarder wasmeren area in the western netherlands late pleistocene cover sands and overlying early holocene drift sands show various paleosols which can be characterized as more or less incipient podzols we dated those soils and sands by radiocarbon analysis and osl and we used biostratigraphical dating based on the known chronology of the vegetation history apart from usselo soils of allerod age we found early holocene soils showing usselo soil characteristics but with relatively advanced podzolisation covered by early holocene early middle holocene drift sands we discuss their age and origin and reflect on the role of fires and ecosystem degradation in the early development of heathland podzols and drift sands in the netherlands prior to any neolithic farming we hypothesize about the possible role of mesolithic man stimulating habitats for corylus avellana by burning pine forest in the longer term inducing the observed ecosystem degradation transformation of forest into open short vegetation acidification and concurrent podzolisation wind erosion this hypothesis is in line with studies in adjacent nw european countries which are reviewed and an alternative for the theory of vera 2000 who assumed that open forests and short vegetation resulted from grazing pressure by large herbivores

contemporaneously erupted tholeiitic and calc alkaline magmas in the archean colomb chaboullie greenstone belt james bay quebec petrologic implications abstract archean greenstone terranes are key to understanding the geological processes active during early earth history these areas are also of economic interest due to their association with volcanogenic massive sulphide vms deposits and several other types of mineral deposits the archean colomb chaboullie greenstone belt is located between the nemiscau and opatica subprovinces of the superior province quebec canada this belt comprises three submarine volcanic units pillowed to massive basaltic lavas variably porphyritic massive to pillowed intermediate lavas intrusions and intermediate to felsic volcaniclastic rocks the calc alkaline intermediate lavas and volcaniclastic assemblages are intercalated with the tholeiitic to transitional basaltic lavas this implies that these volcanic rocks were contemporaneously formed within a limited geographical area the major element trends of the basalts are explained by crystal fractionation while the trace elements are influenced by independently occurring minor degrees of crustal contamination the major and trace element geochemistry of the calc alkaline rocks share many geochemical characteristics with pre existing crustal contaminants we therefore propose that the intermediate and felsic assemblages were produced via crustal contamination and mixing processes within a pre existing magma chamber the basalts spent less time in the crust and had a more direct passage to the surface massive to semi massive au ag cu showings along with associated paleo hydrothermal manifestations are dominantly associated with the basaltic lavas and show evidence of a syn volcanic origin chemo stratigraphy in conjunction with detailed mapping of the gold bearing lac marcaut vms showing allows a basalt basalt contact to be identified which may be favourable for exploration elsewhere in the colomb chaboullie belt

late glacial and holocene history of former salziger see central germany and its climatic and environmental implications an 8 40 m long sediment sequence from the salziger see basin central germany was investigated by a multi disciplinary approach including chronological sedimentological geo and biogeochemical methods radiocarbon dating conducted on ten samples of aquatic and terrestrial fossil remains and the occurrence of the laacher see tephra lst reveal that the sediment sequence comprises the late glacial and holocene lake history since ca 13 800 cal year bp this onset of lacustrine sedimentation is almost 7 000 years earlier as assumed so far the geo and biogeochemical data indicate distinct variations throughout the late glacial which can be correlated with cold and warm periods such as the oldest dryas the bolling the allerod and the younger dryas during most of the holocene minor variations in the geo and biogeochemical data and a high carbonate content due to the formation and precipitation of autochthonous carbonate in the lake indicate relatively stable lacustrine conditions a slight change in the sedimentary conditions between 6 700 and 4 000 cal year bp with lower deposition of carbonate and fine material can be traced back to enhanced subrosion in the basin increased deposition of coarser sediments and a high accumulation of heavy metals document intensive human activity in the region during the past ca 1 000 years

mineralogy of fe mn nodules in albeluvisols in the carpathian foothills poland fe mn nodules are common components occurring in various soils and especially in soils exhibiting imperfect drainage the formation distribution chemical composition size and shape of fe mn nodules are the subject of many studies and the research literature contains a lot of information concerning these issues on the other hand data regarding the mineral composition of fe mn nodules in the soil environment are limited to only a few studies the main aim of the present study was to determine the mineral composition of the fe mn nodules found in albeluvisols in the carpathian foothills in poland using quantitative x ray diffraction qxrd fourier transform infrared spectroscopy ftir and mossbauer spectroscopy ms the obtained results show that fe mn nodules from albeluvisols in the carpathian foothills in poland are composed mainly of silicates quartz k feldspars plagioclases and phyllosilicates dioctahedral mica smectite chlorite and kaolinite which are impregnated with iron and manganese oxides iron minerals are represented by goethite and probably lepidocrocite both iron minerals are characterized by very small particles and poor crystallinity goethite occurring in all of the studied fe mn nodules clearly prevails over lepidocrocite which exhibits a higher concentration only in nodules from the lower part fragipan of the soil profile located on a footslope and showing the strongest stagnic color pattern manganite and todorokite represent manganese minerals however todorokite was observed only in nodules obtained from illuvial horizons btx btg of the studied albeluvisols the fe mn nodules obtained from eluvial horizons eg show higher amounts of silicates quartz k feldspars plagioclases than the nodules obtained from illuvial horizons on the other hand fe mn nodules obtained from illuvial horizons fragipan and argillic exhibit higher amounts of phyllosilicates i e clay minerals in comparison with the eluvial horizon the differences in the quantitative mineral composition of the fe mn nodules between eluvial and illuvial horizons are related to the translocation of clay minerals from upper soil horizons into the lower part of the soil profiles this indicates that the nodules from e horizons were formed after translocation of major portion of clay fraction down the soil profile the similar mineral composition of the fe mn nodules and bulk soil material indicates that the nodules were formed in situ because of cyclic reduction and oxidation of fe and mn oxides

geogenesis pedogenesis and multiple causality in the formation of texture contrast soils abstract coarse over fine vertical texture contrasts vtc are common in soils and weathering profiles in a variety of environmental settings including many where inheritance or surficial processes alone cannot account for them a multiple causality model is presented here which shows that texture contrasts can form in response to a combination of ubiquitous phenomena there are six key elements downward translocation by water erosional winnowing soil mixing by bioturbation the tendency for surface clay additions to be mobilized while subsurface clays are more likely to remain in place and biological facilitation of moisture flux no element alone is sufficient to create a vtc but not all are necessary in any given regolith the model is illustrated by application to case studies in the ouachita mountains arkansas ridgetops in eastern kentucky the lower coastal plain of north carolina and the upper coastal plain of east texas the implications for interpretation of soils paleosols and weathering profiles is that the presence of a textural contrast by itself does not connote any particular set of geogenic or pedogenic processs or controls texture contrasts may be geogenic pedogenic or both given the widespread occurrence of the mechanisms of the multiple causality model vertical texture contrasts are inevitable

giant granulite terranes of northeastern superior province the ashuanipi complex and minto block the ashuanipi complex and minto block of the superior province are large regions that have been classified as high grade gneiss terranes on the basis of the presence of orthopyroxene bearing units like the granite greenstone and metasedimentary subprovinces of the southern superior province the two terranes consist predominantly of intrusive rocks but are distinguished by their primary magmatic orthopyroxene both high grade and gneiss are misnomers because granulite facies gneisses are only sparingly present and the regions consist dominantly of massive unmetamorphosed plutonic rock the ashuanipi complex consists of a deformed metamorphosed package of metasedimentary rocks and primitive early tonalite cut by widespread orthopyroxene garnet granodiorite diatexite as well as plutons of tonalite granite and syenite based on its lithological and chronological similarity and on strike position the complex appears to be the continuation of metasedimentary subprovinces such as the quetico its evolution involved deposition of immature greywacke in an accretionary prism early arc tonalitic magmatism and deformation followed by widespread intracrustal magmatism in the period 2700 2670 ma both metamorphic and igneous rocks record equilibration under granulite facies conditions 700 835 c 0 35 0 65 gpa a 0 3 and indicate exposure levels of 20 km the minto block at the latitude of leaf river consists of several north northwest trending domains of similar scale and diversity to the east trending subprovinces of the southern superior province the central goudalie domain is dominantly amphibolite facies tonalitic rocks including some with ages 3 ga with small belts of volcanic and sedimentary origin lake minto domain contains poorly preserved supracrustal remnants in a plutonic complex comprising hornblende granodiorite clinopyroxene orthopyroxene granodiorite orthopyroxene biotite diatexite and granite the hornblende granodiorite suite constitutes most of the utsalik and tikkerutuk domains and is thought to represent continental arc magmatism on the basis of their distinct aeromagnetic and lithological character two additional domains are evident north of the leaf river area the inukjuak domain in the west and the douglas harbour domain in the east the northerly grain of the minto block appears to have been established in situ with respect to the easterly belts of the southern superior province i e no large scale block rotation during the same interval of time 3 0 2 7 ga modification of the tectonic framework for the superior province is required to explain minto arc magmatism in the interval 2730 2690 ma ago a continental magmatic arc built the berens river and bienville subprovinces and minto block on the southern and eastern edges respectively of a northern protocratonic foundation in the same period primitive volcanic arcs and accretionary prisms developed outboard on oceanic crust and were accreted to form a southern tectonic regime

post glacial environmental history in ne poland based on sedimentary records from the dobrzyn lakeland this paper presents a comprehensive palaeoenvironmental data set from a trough between glacial curvilineations an intra gcl trough of the dobrzyn lake district north central poland a sediment core taken from the depression was investigated to reconstruct late glacial and holocene environmental changes in north central poland using a combination of palynological macrofossil sedimentological and geochemical studies four main development phases of the studied intra gcl trough were distinguished accumulation of the analysed sediments occurred from the late vistulian glacial phase through the late glacial to present times our data suggest the persistence of dead ice in the basin up to the older dryas lacustrine phase the sedimentary record of the depression reflects a considerable difference between the late glacial early holocene and the middle late holocene in terms of environmental conditions the late glacial was characterised by rapid environmental changes while climatic conditions throughout the holocene were relatively stable except for the subboreal period a small lake was strictly dependent on climatically controlled vegetation changes and erosion tendencies in the vicinity of the zbojenko site the lake finally disappeared at the turn of the younger dryas and the preboreal period the preboreal boreal and atlantic periods encompassed the early paludical phase during which the water level used to rise and hence the mire could be flooded the area was covered with dense vegetation and the rate of denudation processes around the site was moderate the late paludical phase included the subboreal and most of the subatlantic deciduous forests with quercus carpinus corylus dominated around the site major changes occurred between the late subboreal and the early subatlanic as a result of the growing human impact on the environment the subatlantic ends with the human impact phase middle age dominated by human impact little accumulation of sediments and highly increased denudation

colluvium definition differentiation and possible suitability for reconstructing holocene climate data abstract this study examines whether colluvial soils store climatic data and if these data can be used as proxies colluvial soils as the correlated sediments of soil erosion represent a widespread geoarchive these soils store the morphology data of the eroded soils and contain clues as to the processes of the eroded soils formation as well as indications of the pedogenesis which took place after the deposition all of these processes are closely related to climatic factors especially rainfall this study discusses the genesis of young soils in colluvial sediments and shows that typical soil features may be related to climatic factors furthermore the study investigates the genesis of anthropogenic colluvial sediments which must be seen as a syngenetical product of relief field size time of usage pressure of population farming technique sediment erodibility deposition area and climatic factors to this end pedogenic features are separated from the sedimentological features the results show that the reconstruction of all factors which control the genesis of the formation of a colluvium is still not yet possible this is the necessary precondition for colluvial soils to yield proxy climate data or for the data to be correlated with already existing holocene climate archives as the results of our discussion are ambiguous in their interpretation we conclude that colluvial soils which clearly include climatic information cannot be used for the reconstruction of proxy climate data at present

conditions and timing of metamorphism in the southern abitibi greenstone belt quebec regional metamorphism ranging in grade from the subgreenschist facies to the greenschist amphibolite facies transition affects all archean supracrustal rocks 2677 ma in the rouyn noranda area contact metamorphic minerals associated with the posttectonic preissac lacorne batholith 2643 ma show no evidence of a regional retrograde event accordingly the age of regional metamorphism can be bracketed between 2677 and 2643 ma three reaction isograds were mapped in subgreenschist facies metabasites dividing the low grade rocks into three metamorphic zones the pumpellyite actinolite zone the prehnite pumpellyite zone and the prehnite epidote zone in addition the pumpellyite actinolite epidote quartz bathograd corresponding to a pressure of approximately 200 mpa occurs on both sides of the porcupine destor fault low pressure regional metamorphism is also indicated both by the occurrence of an actinolite oligoclase zone and the persistence of pre regional metamorphic andalusite the coincidence

a statistical model of extreme storm rainfall a model of storm rainfall is developed for the central appalachian region of the united states the model represents the temporal occurrence of major storms and for a given storm the spatial distribution of storm rainfall spatial inhomogeneities of storm rainfall and temporal inhomogeneities of the storm occurrence process are explicitly represented the model is used for estimating recurrence intervals of extreme storms the parameter estimation procedure developed for the model is based on the substitution principle method of moments and requires data from a network of rain gages the model is applied to a 5000 mi2 12 950 km2 region in the valley and ridge province of virginia and west virginia

holocene sediment fluxes in a fragile loess landscape saxony germany abstract the loess region of the central saxon hill country is characterized by a relief of gently rolling hills whose most distinctive landscape elements are well defined shallow valleys called dells the aim of this research is to gather morphodynamic information on the dells in a qualitative and quantitative way by means of high resolution field mapping and laboratory based analyses the intensity of sediment shifting has been modelled via sediment budgeting on a small catchment scale research objectives are to determine the character and magnitude of geomorphic processes for a holocene time frame concerning the absence of currently obtainable dating this study represents a reflection which summarises all sediment shifting related to anthropogenic land use during the holocene as a specific parameter in terms of landscape development the relief is considered to be strongly associated with varying process intensities agrarian land use of the loess region since the late neolithic has resulted in severe soil erosion lower middle slope positions are the apparent spots were soil erosion processes take place in terms of rill erosion a detailed survey of three dells provided a very heterogeneous pattern of the relocation of soil material dell 1 zehren shows medial holocene soil profile truncation of 1090 mm in contrast dell 3 lobschutz shows soil loss of around 660 mm all systems have similarly high slope gradients up to 12 actually the deepening of the dell s depth contours and therewith the extent of erosive slope lengths is varying thus a higher longitudinal decline of the valley floors and a more intensive incision lead to enlarged erosive slope lengths which causes increasing sediment transport hence land use patterns trigger the process of material displacement whereas relief modifies the intensity of geomorphic processes

soil formation on calcium carbonate rich parent material in the outer carpathian mountains a case study abstract in this study ten stratified calcium carbonate rich soil profiles from the polish outer carpathians were investigated in order to identity the influence of parent material variability and slope processes on soil diversity and their evolution moreover we evaluated the morphological and physico chemical soil properties to recognize the diagnostic horizons and classification of such soils while it is usually thought that carbonate rich soils are considered as formed in situ these study soils clearly presented layering and contribution of materials as they were developed from mixed substrates of different origin e g as the result of mass movements and possible aeolian silt contribution irrespective of the type of parent material every investigated soil showed traces of slope processes resulting in heterogeneous soil profiles further a few different patterns of primary calcium carbonate arrangement were found in general the studied soils were characterized by enrichment with calcium carbonate not only due to inheritance from calcium carbonate rich parent material but also translocation of calcium carbonate within soil profiles the latter depending on soil stratification based on the obtained results four pathways of soil evolution were formulated leptosols which represent initial calcium carbonate rich soils may evolve in different directions first formation of the thick layer suitable for cambic horizon development under deciduous forests which enables the classification of such soils as cambisols depends on slope processes and allochthonous material deposition in turn the decrease of mineralization rates for organic matter delivery of soil material from the upper parts of the slope as well as mixing of organic matter by mesofauna result in the formation of mollic horizons and transformation of leptosols into phaeozems further erosion and redeposition of fine soil material provide two types of slope sediments i those with silt loam texture dominance and ii clay loams interstratified with silty substrates the first type of sediments are more suitable for water percolation and after carbonate leaching clay dispersion and translocation occur in such materials luvisols may develop sediments with a prevalence of clay loam aided stagnosol formation in which pools of carbonates were stabilized due to the reduction of water percolation leading to stagnation

late glacial early holocene environmental changes in thuringia germany stable isotope record and vegetation history abstract the 7 m thick sediment profile at plinz in northern thuringia central germany covering the time span between 10 000 and at least 8000 14 c years bp about 11 600 9000 cal bp was studied using radiocarbon stable isotopes and pollen analysis the results reflect the very fast climatic transition from the late glacial to the holocene as a change from cold and dry to warmer and wetter conditions a short climatic deterioration during the preboreal oscillation pbo at around 9800 14 c years bp is clearly reflected by a sharp drop in the pinus concentration accompanied by a considerable increase in betula salix various herbs and the distinct occurrence of aquatic plants during the preboreal stable isotopes of biogenic carbonate show several episodes with altered levels of atmospheric moisture continuous climatic improvement without any oscillations can be suggested for the period covering the end of preboreal and the boreal

age and source of colluvial sediments at vaihingen enz germany abstract colluvial sediments accumulated on the lower slopes of a ridge as a result of past and present soil erosion were dated by optical 14 c and archaeological methods this allowed us to reconstruct the depositional history of the colluvium and also to identify temporary sedimentary sinks in its transportational pathway a cascade model of colluvium formation is developed colluvial sediments resulting from early soil erosion in the neolithic to iron age periods were mainly deposited on the upper slopes significant deposition on the lower slope occurred for the first time during the iron age and roman period since then deposition rates have increased because of more intensive land use

source of gold in neoarchean orogenic type deposits in the north atlantic craton greenland insights for a proto source of gold in sub seafloor hydrothermal arsenopyrite in the mesoarchean abstract given that gold au mostly remained in the incipient earth mantle until ca 3 9 3 8 ga a proto source of gold may have been present in the dominantly mafic crust precursor born through first stage melting of the early earth mantle in south westernmost greenland a fragment of the north atlantic craton is characterised by greenstone belts comprising mafic volcanic and magmatic rocks and harzburgite cumulates that were emplaced at ca 3 0 ga prograde amphibolite facies metamorphic assemblages and caused local dissolution of arsenopyrite during this retrograde tectono metamorphic stage in gold rich shear zones the re os geochronometer in arsenopyrite was reset to a neoarchean age while invisible gold was liberated and deposited as free gold with 2 66 ga pyrite re os isochron ages the initial os isotope ratios of neoarchean arsenopyrite 187os 188osi 0 13 0 02 and gold bearing pyrite 0 12 0 02 overlap with the estimated 187os 188os ratio of the mesoarchean mantle 0 11 0 01 and preclude contribution of radiogenic crustal os from evolved lithologies in the accretionary arc complex but instead favour a local contribution in os from basaltic rocks and serpentinised harzburgite protoliths by metamorphic fluids thus the ca 2 66 ga lode gold mineralisation identified in the north atlantic craton may illustrate a gold endowment in shear zones in earth s stabilizing continental crust at the time of the 2 75 2 55 ga global gold event through metamorphic upgrading of bulk gold which had originally been extracted from the mesoarchean mantle and concentrated in hydrothermal arsenopyrite deposits in oceanic crust beneath the overall reduced mesoarchean ocean

properties and formation of black soils on the island of poel ne germany abstract recent soil mapping on the island of poel situated in the southern baltic sea shows an abundance of black soils developed in stratified parent material whereby the upper layers are of periglacial origin covering calcareous till the black soils have been formed in the upper layer overlying luvisols developed in decalcified till with different degrees of stagnic influence the luvisols are not the result of a degradation of the black soil as no humic clay coatings were detected in their bt horizons with a simplified ap ah eb ah 2 e 2bt g b c horizon sequence these soils differ from the better known degraded phaeozems on fehmarn and the uckermark region the properties of three pedons are presented and their pedogenesis is discussed ams 14c ages from soil organic carbon of the ah horizons from the black soils suggest that the development of the luvisols stopped within the first half of the subatlantic period

slope deposits as an indicator of anthropopressure in the light of research in central poland abstract results of research on neo holocene slope covers uncovered at archaeological sites in central poland are described in this paper geoarchaeological investigations have been undertaken in the ner river basin distinctive archaeological relicts of human activity document periods of intensive activity of human societies artefacts included within deposits play a very important role in correct recognition of the chronology of covers and ecofacts for reconstructions of environmental evolution the origin and development of slope covers have been correlated with anthropogenic changes of the natural environment two main phases of acceleration of slope processes have been recognised dated to the middle bronze age and to the late roman period slope deposits have been classified as deluvia deluvial slope wash deposits or colluvial deposits their features are most typical for deluvial sands and if they contain more humic matter for soil deluvia the deluvial covers have been deposited as an effect of moderately intensive slope wash processes accumulation of slope deposits has resulted from natural processes initiated by human impact during periods of intensive settlement and economic activity the slope cover sediments are the source for recognition of intensity of human impact and of economic activity of ancient societies and for distinct phases of hiatuses of settlement development the possibility of archaeological and palaeogeographical interpretations based on research on slope covers at archaeological sites is presented

sediment source and storage in small watersheds on the keuper marls in luxembourg as indicated by soil profile truncation and the deposition of colluvium abstract soil survey reports and soil maps of 11 second order watersheds on the keuper marls in luxembourg were used to establish the extent to which soils were modified by accelerated erosion and colluviation and to calculate the volume of colluvium the amount of truncation of the soil profiles in the eroded area is on average 55 cm of which the equivalent of 36 cm remains in the watersheds as colluvium the 34 of the eroded soil material that has left the watersheds represents the longterm sediment delivery ratio landuse exerted a more powerful control on the production of colluvium than geomorphology the area occupied by colluvial soils c ha which offer good quality land can be predicted from the area under agriculture l ha with the equation c 74 l 56 comparison with palynologically dated colluvium produced figures for sediment yield of the source areas in the range between 700 and 1800 kg ha year

experimental approach of lessivage quantification and mechanisms abstract lessivage also called argilluviation consists of a substantial vertical transfer of particles less than 2 m from a superficial departure horizon to a deeper horizon this process is common in many soil types and responsible for the development of a textural differentiation in soil profiles in the subsurface however the mechanisms of lessivage are still poorly understood and to our knowledge lessivage has rarely been quantified we propose here two original experiments of in vitro pedogenesis on soil columns to analyse the mechanisms acting in eluviation and illuviation the two phases of lessivage and to quantify these two phases in terms of particle export and fixation we paid special attention to the experimental conditions so that the conditions were favourable for lessivage and as close as possible to field conditions the eluviation experiment showed that the release of particles was not the determining process for lessivage we also showed that the smectite selectivity of eluviation was not continuous over time both physical and chemical processes were identified as acting on both eluviation and illuviation concerning illuviation experiments showed that from 25 to 90 of the eluviated particles were retained in the deeper horizon although large to our knowledge this range represents the first quantification of illuviation

u pb geochronology of the opatica tonalite gneiss belt and its relationship to the abitibi greenstone belt superior province quebec u pb ages for zircon monazite and titanite from samples collected from two transects across the opatica tonalite gneiss belt in the superior province of quebec indicate that the belt contains rocks that are significantly older than those in the adjacent low grade northern abitibi belt tonalite and tonalite gneiss which make up most of the belt formed over an interval of 100 ma from pre 2800 to 2702 ma five samples have ages of ca 2807 13 2773 23 and 2702 3 ma zircon growth at 2718 2721 ma in the two oldest samples may record an early period of high grade metamorphism in the belt hornblende diorite monzodiorite and tonalite plutons were intruded at 2693 2696 ma particularly along the southern boundary with the abitibi belt these include the canet pluton at ma the lac ouescapis pluton at 2693 2 ma and the barlow pluton at 2696 3 ma pink granite plutons and dykes are the youngest intrusive rocks in the belt three samples have yielded zircon ages of 2690 2 and 2686 4 ma

truncation and accretion of soil profiles on coastal plain croplands implications for sediment redistribution soil stratigraphy and morphology in a small agricultural watershed on the coastal plain at clayroot north carolina indicate long term decadal scale patterns of the redistribution of sediment the most dramatic truncation of the soil profile occurs on convex upper slopes and suggests tillage and aeolian erosion as the major processes of soil loss thicker soils immediately downslope from convexities are consistent with redistribution by tillage but significant aeolian soil loss also occurs from some fields thinner apparently truncated soils were also associated with relatively steeper lower slope areas where contemporary rilling was observed the presence of thicker cumulic soils at toeslopes where small fans are observed at rill termini and about a half meter of alluvium in drainage ditches indicates that water erosion is also quite prominent distinctive soil stratigraphy is found in areas of aeolian deposition where podzolization in sandy surface deposits has created compound soil profiles on convex slopes tillage and wind erosion result in net soil loss with the former dominating on wetter soils and when plowing occurs and aeolian processes dominating on drier hilltops and when no till or minimum tillage practices are followed soils are thicker immediately downslope from convexities with thinner soils and rill erosion on lower slopes thickened soils and colluvial deposition in the form of thin fan deposits occur at toeslopes and in depressions the borders of fields often have thicker soils because of aeolian deposition water wind and tillage processes are all significant in soil redistribution at the clayroot site with relative importance in space and time controlled by topography soil properties seasonal moisture and vegetative cover and tillage practices

lake belau and its catchment northern germany a key archive of environmental history in northern central europe since the onset of agriculture the environmental history since the onset of agriculture was reconstructed from sediments and soils in the catchment area of lake belau schleswig holstein northern germany the established chron

the preboreal oscillation around the nordic seas terrestrial and lacustrine responses the occurrence of an early preboreal climatic cooling oscillation pbo in lacustrine and glacial records from northwest europe iceland and greenland is reviewed and documented the often subtle response of the proxy records to this oscillation in combination with its short duration make it difficult to detect owing to its chronostratigraphic position between the 10 000 9900 and 9600 9500 14 c plateaux c 11 300 11 150 calendar yr bp it is also difficult to 14 c date with precision we find that the vegetation response to the pbo varies between sites and regions in contrast to the pioneer vegetation in iceland and southern sweden the expanding birch pine forest in germany denmark was more susceptible to deteriorating growing conditions the combined lacustrine tree ring and glacial records imply that the pbo was characterised by cool and humid conditions throughout northwestern and central europe this is documented by vegetation changes decreased aquatic production increased soil erosion increased 2 h and 13 c content in tree rings readvances or stillstands of the ice sheet in norway and finland and ingression of brackish water into the baltic icelandic proxy records from lake sediments and glacial moraines imply cooler conditions than during the previous preboreal period but not as extreme as during the younger dryas greenland records suggest that the early preboreal was characterised by ice readvances as an effect of cool climate and increased precipitation in relation to the younger dryas it was not until the end of the pbo that climate was warm enough to melt the land based ice sheet this preboreal oscillation found on both sides of the nordic seas is interpreted as an effect of increased freshwater forcing on the thermohaline circulation in the nordic seas which is implied by a simultaneous and distinct rise in the atmospheric 14 c 12 c ratio a slow down of the thermohaline circulation may tempor arily have pushed the polar front further south 1997 by john wiley sons ltd preboreal oscillation thermohaline circulation lacustrine records glacial records chronology

historical soil erosion by water in germany scales and archives chronology research perspectives abstract the published record of historical soil erosion by water in germany as deduced from dated slope deposits n 306 alluvial sediments n 120 and lake sediments is summarized in this paper the number of sediments investigated reflects the state of knowledge chronology of historical soil erosion and to a certain degree the intensity of the human impact on german landscapes during the holocene even though few data of calculated historical soil erosion intensities exist an estimation of historical soil erosion in germany combining the available data has been calculated soil erosion in germany occurred first locally during the early holocene probably triggered by climatic variability from the neolithic onward the record reflects the human impact according to agricultural land use the observed variability indicates phases of weaker and regained intensity of agricultural land use in germany few records characterise the early and middle bronze age ca 2000 1600 bc and the migration period and the early medieval times ca 400 1000 ad surprisingly for the roman emperor times ca 1 400 ad a decreasing number of soil sediments is recorded even when the data from southern germany is examined separately phases characterised by an increase in soil erosion were the late bronze age and pre roman iron age ca 1600 bc 1 ad the high and late medieval times ca 1000 1350 ad and the modern times ca 1500 ad until today some extraordinary heavy precipitation events late 18th early 19th first half of 14th century pre roman iron age topped the even high soil erosion intensities research gaps as well as potential for future research as derived from the available data are outlined

rapid climate change during the early holocene in western europe and greenland based on microfacies analyses of seasonally laminated varved sediments from lake holzmaar germany we report evidence of decadal to century scale climate variability during the early holocene the shifts in climate are documented in the thickness variations and changes in the composition of the varves in response to subtle shifts in limnological conditions the close similarity between the holzmaar varve record and the grip oxygen isotope record during 7 4 9 0 calendar cal ka suggests that the high frequency climatic variations in both regions were controlled by the same mechanism our more detailed studies covering the central 409 yr period 7 846 8 255 cal ka encompassing the 8 2 ka event document for the first time on a seasonal scale the changing precipitation regimes in western europe during these climate shifts we show i that winters were drier and summers shorter and cooler in western europe during colder periods in greenland ii in contrast to the present day climate in the holzmaar

origin of reversible cementation and brittleness of the fragipan horizon in albeluvisols of the carpathian foothills poland abstract fragipan horizon is a natural subsurface soil layer exhibiting higher bulk density and lower porosity in comparison with the overlying horizons significantly restricting infiltration of water and root penetration in contrast to hard and cemented horizons e g duripan clods of the fragipan horizon btx slake or fracture immediately when placed in water the most interesting issue concerning genesis and properties of the fragipan horizon is its reversible cementation i e very hard consistence in dry state and brittle consistence in moist state the main objective of the present study was to explain and improve the understanding of the specific consistence of the fragipan horizon in moderately humid climate on the example of albeluvisols of the carpathian foothills in poland basing on mineral and chemical composition of bridges linking coarse soil material quantitative x ray diffraction shows that the studied fragipan horizon contains high concentration of swelling clay minerals soil material from the fragipan horizon exhibits numerous clay and iron clay coatings and clay infillings indicating translocation of colloidal clay and iron oxides from overlying horizons in addition bridges between coarse grains of the soil material occur the fragipan cementing material is composed mainly of sio2 al2o3 and fe2o3 with lower concentration of k2o mgo cao and na2o the chemical composition of bridges within the pan is similar to that of clay coatings and clay infillings suggesting that clay minerals are major bonding agents and are responsible for brittleness and more friable consistence of the pan in the moist state additionally free iron aluminium and silica may play some role in specific cementation of the investigated fragipan horizon but these elements are not main bonding agents

magma mobilization by downward propagating decompression of the eyjafjallajokull volcanic plumbing system 1 detailed observations of the 2010 eyjafjallajokull eruptions in iceland show seismic activity propagating vertically through the entire crust during a ten week period of volcanic unrest comprising multiple eruption episodes systematic changes in magma chemistry suggest a complex magmatic plumbing system tapping several accumulation zones at different depths containing magma of differing ages and compositions during the eruption a systematic downward propagation of seismicity through the crust and into the upper mantle to 30 km depth occurred in a series of steps each of which preceded an explosive surge in eruption rate here we show that the sequence of seismicity and eruptive activity may be explained by the downward propagation of a decompression wave that triggers magma release from progressively deeper sills in the crust comparing observations of the downward propagating seismicity with the decompression of a series of model elastic sills suggests that each sill was 1 10 km3 in size

stratigraphy and age of colluvial deposits indicating late holocene soil erosion in northeastern germany abstract in the focus of this study are the sedimentary characteristics chronology magnitude and causes of past soil erosion dynamics of an agriculturally intensively used glacial lowland landscape from the mesoscale quillow river catchment sedimentary sections bearing colluvial sediments from different landforms were analysed to explore their geoarchive potential and to establish a local chronology of late holocene soil erosion sections from footslopes contain a rather simple stratigraphy with one topping colluvial horizon of up to 1 m thickness burying a palaeosol in contrast glacial kettle holes preserve more complex sequences partly having several colluvial layers with intercalating palaeosols the most complex stratigraphy is associated with a kettle hole being the ultimate sediment trap for a dendritic gully system forming a 4 m thick sequence of alternating peat and colluvial layers thirty osl ages and 13 radiocarbon ages are used to reconstruct phases of soil erosion potentially human induced soil erosion which is corroborated by local archaeological and palynological data can be traced back to the last c 4000 years the oldest colluvial deposits date back to the late bronze age most datings however cluster within the last 600 years with a peak in the last 200 years ascribing the main phase of local soil erosion to the recent past thus although numerous archaeological finds are detected in the catchment since the neolithic considerable agricultural soil erosion does not occur before the last millennium a compilation of osl chronologies based on colluvial sediments from other regions in central europe shows a more complex erosion history there with a pronounced two or three phased distribution of ages primarily dating into the last c 4000 5000 years this study underlines that in northeastern central europe human impact on landscapes was effective apparently at a later stage as compared to some adjacent regions

regional flood frequency analysis using extreme order statistics of the annual peak record a regional flood frequency model is developed for estimating recurrence intervals of extreme floods the regionalization procedure developed in this paper differs notably from the u s geological survey index flood method dalrymple 1960 in that a large quantile rather than the mean annual flood is used as the index flood based on a result from extreme value theory exceedances of the specified quantile are modeled by a generalized pareto distribution the generalized pareto distribution has two parameters a scale parameter and a shape parameter it is assumed that the shape parameter does not vary from basin to basin implying that annual peak distributions for all basins have the same upper tail thickness the scale parameter on the other hand not only varies from basin to basin but may also depend on covariate information such as drainage area or indicator functions for basin geology likelihood based inference procedures are developed for the regional flood frequency model the model is applied to extreme floods of the central appalachian region of the united states

lower to middle weichselian pedogenesis and palaeoclimate in central europe using combined micromorphology and geochemistry the loess paleosol sequence of alsheim mainz basin germany abstract lower to middle weichselian loess loess derivatives and buried soils of the loess paleosol sequence alsheim central europe were characterised by particle size distribution geochemical and micromorphological data high rates of sedimentation with alternating phases of relocation are the main cause for a much less differentiation into middle and upper weichselian loess paleosol units of the alsheim loess paleosol sequence compared to other loess paleosol sequences e g nussloch near heidelberg whereas the lower weichselian has distinct phases of pedogenesis resulting in ah bw and btw horizons to distinguish between different loess deposits locally and intraregional the degree of fineness is an easily applicable and suitable tool though inappropriate for interregional comparisons the chemical index of alteration cia is low 53 to gallet et al 1998 the highest weathering was detectable for btw horizons with cia values 70 a direct quantitative estimation of mean annual palaeotemperature and mean annual palaeoprecipitation can be provided by calculations based on geochemistry of soil horizons and sediments the present mean annual precipitation map in the mainz basin is 789 mm in contrast palaeoprecipitation data suggest a 150 mm higher amount for the last interglacial btw horizon a much lower amount of around 300 400 mm mapp periods of loess and sandy loess deposition and a mapp of micromorphology shows compacted granular structure and moderately to strongly developed pedality as characteristic properties for aquatic loess whereas channel microstructure with no pedality is typical for loess deposits spongy microstructure suggests a classification of the lower weichselian mosbach humus zones as chernozems the eemian paleosol btw horizon in als iii has only weak clay illuviation characteristic for drier regions in europe palaeoclimate and soil formation of the last glacial interglacial cycle calculated from geochemistry and micromorphological data are in good accordance with other proxy data in central europe this suggests that paleoclimate reconstruction based on palaeopedological analyses could be successfully implemented in europe such data may provide a useful alternative to other proxies for correlating european records

recycled loesses a micromorphological approach to the determination of local source areas of weichselian loess the article presents the results of micromorphological studies of selected neopleistocene loess palaeosol sequences broader studies of thin sections are presented for the polanow samborzecki zlota site they served as models for analysis for similar targeted observations in other sequences on their basis 3 groups of microfeatures litho pedo and cryogenic were described an additional group are pedogenic features clay concentrations selected fe and mn fe nodules as well as charcoals documented in non soil locations generally limited to loess macroscopically defined as primary an analysis of these features shows that these are redeposited pedogenic microfeatures occurring in a secondary location according to this genetic interpretation they can be identified as pedorelicts and possibly also as lithorelicts these features clearly show that the older pedogenically modified layers were involved in the formation of younger loesses these studies show that the younger loesses are partially built of older loess material

luvisols or cambisols micromorphological study of soil truncation in young morainic landscapes case study brodnica and chelmno lake districts north poland abstract eight soil profiles in brodnica lake district and chelmno lake district were described and sampled the profiles were divided into four pairs study areas dissimilar in lithology relief or land use each pair of profile contained soil located on the crest or upper slope exposed to erosion and back slope slightly exposed to erosion positions the relief of this area is inherited from the last vistulian glaciation and represents mostly flat and hummocky moraine plateau landscapes all investigated pedons have a b horizon five profiles have vertical contrasting texture and contain a significantly developed eluvial zone a and e horizons above b horizon in three cases pedons have a b c horizon sequence to date numerous studies have shown that the soils with a b c profiles developed on moraine tills should be treated as cambisols on existing soil agricultural maps these soils are also marked as cambisols the b horizons are enriched in the clay fraction and contain low amount of carbonates in comparison with the parent material all these criteria can be used to distinguish a cambic horizon but analysis of thin sections revealed the presence of significant amounts of clay and silt illuvial features the illuvial pedofeatures resulted in these horizons being classified as argic horizons bt these soils cannot be classified as cambisols which are characterized by absence of appreciable amounts of illuvial silt and clay instead the a b c profile forms represent truncated luvisols in which the material from eluvial horizons was entirely removed the soils described in this study occur in areas where soil erosion is common the upper part of slopes and crests in arable areas the illuvial origin of b horizons in truncated pedons a b c was also confirmed by the presence of eluvial horizons in nearby soils on the back slope position slightly or non exposed to erosion the results showed that accelerated erosion had a significant role in development of soil cover in agriculture moraine landscapes of brodnica and chelmno lake districts the micromorphological analysis confirmed that the loamy soils with the a b c profile developed on ground moraine tills should be classified as truncated eroded luvisols the b horizons of these soils have significant accumulation of clay and silt features the illuvial microforms are the relic feature of eluviation illuviation lessivage process the material from the eluvial horizons of luvisols was entirely removed this study is important to understand the influence of soil erosion processes on soil cover development in young glacial regions further investigations concerning formation and characteristic of a b c soils and appropriate classification of described pedons are very important for understanding the impact of accelerated erosion in young glacial landscapes

environmental changes of a shallow kettle lake catchment in a young glacial landscape sumowskie lake catchment north central poland abstract on the basis of detailed analysis sedimentological palynological macroremains geochemical and gis analysis the development of the sumowskie paleolake was reconstructed obtained results led to distinguish three main stages of the evolution of the basin and its catchment during the late glacial and the holocene the lacustrine stage the lake overgrowth stage and the post lacustrine stage study site is located in the western part of the brodnica lakeland north eastern poland within the former sumowskie lake bottom multidisciplinary research was conducted for two cores sedimentological palynological plant macroremains sum a 149 cm and sum c 51 cm and the soil profile sum 3 sedimentological geochemical gis analyses land cover and water level changes were carried out for the nowadays sumowskie lakes catchment it was confirmed that climate was the most important factor influencing the evolution of the lake and its surrounding although the role of this factor decreased in the neo holocene period in favor of rapidly growing human impact changes of the water level were much more abrupt and lasted longer e g 9500 5000 bp hiatus caused by the water level decrease than in other described basins of the region due to the specific geomorphologic situation shallow kettle basins could alternately act as lakes and wetlands as they are well spread in the young glacial area the strong influence of this abrupt and long term events should be reconsidered

landscape history since the saalian drenthe stadial in the widawa catchment area in silesia poland a case study on long term landscape changes abstract with the pre roman iron age approximately in the 2nd century bce a cluster of iron smelting sites began to develop in the catchment area of the widawa river located in the old drift landscape of northeastern silesia poland before this area became an important local center for early iron smelting during the late pre roman iron age to the roman period its landscape had undergone distinct changes since it was covered for the last time by ice sheets during the saalian drenthe stadial besides climate driven environmental and landscape changes during the late pleistocene and holocene the area is influenced by a settlement history since the mesolithic in order to understand the holistic development of this pre roman iron age iron smelting cluster this paper investigates the late pleistocene landscape history of the southeastern part of the widawa catchment with a focus on study sites in the context of early human impacts therefore a multi proxy approach was applied integrating geomorphological mappings and sedimentological analyses lithology particle grain size bulk parameters total inorganic and organic carbon of selected drilling transects dated by ams radiocarbon with archaeological records geological and topographical data the study area developed its present shape in six main phases subsequently to the last ice coverage a which extensively accumulated saalian glacial till the widawa valley initially developed its present directionality b the subsequent valley formation is characterized by a succession of accumulation phases of glaciofluvial deposits of the drenthe c and warthe stadial d and fluvial deposits of the weichselian glacial period e and the holocene f which each were followed by a subsequent incision of the widawa valley first human impacts on the sediment budget are represented by alluvial fan deposits which accumulated at the end of the 4th millennium bp this alluvial fan situated in the context of three prehistoric slag sites shows a complex sedimentological succession of charcoal dated fan sediments that indicate a human impact on the landscape development during the pre roman iron age and the roman period pointing to a temporal and spatial context of early iron smelting

topography reconstruction of eroding landscapes a case study from a hummocky ground moraine carbozalf d abstract erosion processes aggravated by human activity have a large impact on the spatial variation of soil and topographic properties knowledge of the topography prior to human induced erosion paleotopography in naturally stable landscapes is valuable for identifying vulnerable landscape positions and is required as starting point for erosion modelling exercises however developing accurate reconstructions of paleotopography provide a major challenge for geomorphologists here we present a set of paleotopographies for a closed kettle hole catchment in north east germany 4 ha obtained through different reconstruction approaches current soil and colluvium thickness estimated from a dataset of 264 soil descriptions using ordinary kriging were used as input for a mass balance or were compared with a set of undisturbed soil thicknesses to estimate the amount of erosion the performance of the different approaches was assessed with cross validation and the count of mispredicted eroded depositional or stable landscape positions the paleotopographic reconstruction approach based on the average thickness of undisturbed soils in the study area showed the best performance this thickness 1 00 m is comparable to the average undisturbed soil thickness in the region and in line with global correlations of soil thickness as a function of rainfall and initial caco3 content the performance of the different approaches depended more on mispredictions of landscape position due to the assumption of a spatially constant initial soil depth than on small variations in this depth to conclude we mention several methodological and practical points of attention for future topography reconstruction studies concerning data quality and availability spatial configuration of data and other processes affecting topography

woodland history in the upper harz mountains revealed by kiln site soil sediment and peat charcoal analyses charcoal is abundant in various soils and soil sediments and is basically the result of either natural wildfires or of anthropogenic ignition compositions of charcoal assemblages are the result of several taphonomical processes beside this little is known about the influence of charcoal from anthropogenic origin like charcoal production sites kiln sites on soil charcoal assemblages to elucidate how human charcoal production as well as erosion of the relicts of kiln sites influenced charcoal assemblages in soils and mires a multi proxy approach was applied at two transects on the renneckenberg a steep slope in the low mountain range harz germany on this slope three types of archives soil soil sediments kiln sites and peatland were investigated each with different methods on a local scale soil charcoal analyses kiln site charcoal analyses peat macro micro charcoal and pollen analysis the kiln site charcoal records are taxonomically richer in wood taxa than those from colluvial assemblages especially regarding deciduous tree species fagus sylvatica and acer sp are rare or absent in the colluvial charcoal assemblages which are dominated by picea charcoal at the bottom of the slope the soil charcoal concentration is very high and indicates strong erosion of charcoal from the upper part of the slope significant taxonomical discrepancies between the colluvial and the kiln site charcoal assemblages may be related to different fire intensity throughout the holocene and to human woodland usage additionally changes in the run off intensity and fire frequency are detected in the peat macro charcoal record reflecting vegetation change in the early holocene the micro charcoal content coincides with the main mining phases in the late holocene and the 9 2 k climatic anomaly

settlement and environmental history of a multilayered settlement mound in niederroblingen central germany a multi proxy approach a multi disciplinary palaeoecological approach on a sequence of dated archaeosediments was accomplished the sediments derive from a multilayered prehistoric settlement mound in central germany representing the remnants of a prehistoric village based on the analysis of biological remains and geochemical physical analysis of the settlement layers its environment was reconstructed there is a trend to increasing anthropogenic activities and impact on the environment represented through a rise of indicators for productive surplus from the early neolithic 5300 4900 bc until the roman times 400 ad during the early neolithic shifting flat settlements were situated in a locally opened landscape the immediate surrounding of the floodplain was used by the settlers for their economic requirements e g wood from the riparian forest after a hiatus of ca 1900 years a multilayered settlement mount rose from late neolithic times 3000 bc to roman times since the middle bronze age approximately 1500 bc the riparian forest was obviously replaced by agricultural fields and meadows and henceforward the hinterland used by the settlers probably grew in size the continuing demand of wood was maintained by the acquisition of more distant sources the onset of house constructions substituting wood by loam wattle and daub might be a possible societal response to this shortfall this is reflected in the growing thickness and composition of the settlement layers as well as in the archaeological record e g tumbled wattle and daub house walls the rising of the groundwater table and the start of severe floods of the adjacent river helme during pre roman iron age approx 800 100 bc might reflect a geomorphological response to the increased land use intensity at a regional scale

neoarchean disaggregation and reassembly of the superior craton the southern and western superior craton of canada swsc is widely considered to be a tectonic collage accreted from north to south by multiple coeval subduction zones we propose an alternative non plate tectonic scenario where swsc continental fragments are not exotic but derived by partial disaggregation of a heterogeneous older superior i craton in response to a mantle overturn event that started at ca 2780 ma during overturn radial mantle outflow stretched and disaggregated the lithosphere to create the concentric neoarchean fabric of the superior craton the southern part of which swsc broke up into ribbon continents separated by oceanic tracts neoarchean calc alkaline magmas record interaction between plume related magma and older crust a change in the mantle flow field at ca 2720 ma caused southward drift of the northern superior cratonic block as a result of mantle traction on its lithospheric keel and swsc terranes accreted to its leading edge

the record of hydroclimatic changes in the sediments of a kettle hole in a young glacial landscape north central poland abstract multidisciplinary research on the bottom sediments of a kettle hole at the retno site the brodnica lake district north central poland provided some information about changes in hydroclimatic conditions in the late glacial and the holocene detailed analysis sedimentological palynological macroremains geochemical and radiocarbon dating helped to identify 6 stages in the development of the depression in the village of gaj near retno lake with 11 phases of hydroclimatic conditions sediments of the retno profile with a total thickness of 6 72 m reflected individual natural stages in the development of the depression from a lake to a peat bog most of the environmental changes were gradual a sequence of late glacial and early holocene lacustrine sediments mainly gyttja occurred in the floor of the profile the upper 4 10 m consisted of paludal deposits peat of transitional and raised bogs divided at a depth of 1 56 1 54 m b g l by a thin layer of clay dated late subboreal early subatlantic the presence of this layer indicates a sudden change in the environmental conditions associated with a water level rise at that time denudation processes started within the drainage basin probably induced by human activity the important effects related to contemporary anthropopressure included desiccation of the peat bog muck formation in the uppermost 10 cm layer and elevated trophic conditions resulting in a change of the vegetation cover

past hydrological events reflected in the holocene fluvial record of europe abstract a comprehensive database of radiocarbon dated fluvial units in great britain poland and spain has been compiled to investigate the relationship between environmental change flooding and holocene river dynamics following the methodology recently developed by macklin and lewin macklin m g lewin j 2003 river sediments great floods and centennial scale holocene climate change journal of quaternary science 18 101 105 radiocarbon dates in fluvial sequences that coincide with a modification in sedimentation rate or style have been highlighted allowing geomorphologically significant changes in holocene river activity to be identified data analysis has been undertaken at both national and sub national scales and on catchments of different size type and land use history multiple phases of higher flood frequency characterized by accelerated erosion and sediment deposition on floodplains are recognized and compared with a range of climate proxies the relative and varying roles of climate and land use on river dynamics are considered and the value of the database for reconstructing past hydrological events as well as for predicting river response to future environmental change is assessed

a stable isotope tree ring timescale of the late glacial holocene boundary late glacial and holocene tree ring chronologies like deep sea sediments or polar ice cores contain information about past environments changes in tree ring growth rates can be related to past climate anomalies and changes in the isotope composition of tree ring cellulose reflect changes in the composition of the atmosphere and the hydrosphere we have established a 9 928 year absolutely dated dendrochronological record of holocene oak quercus robur quercus petraea and a 1 604 year floating late glacial and early holocene chronology of pine pinus sylvestris from subfossil tree remnants deposited in alluvial terraces of south central european rivers the pine sequence provides records of dendro dated 14c 13c and 2h patterns for the late younger dryas and the entire preboreal 10 100 9 000 yr bp through the use of dendrochronology radiocarbon age calibration and stable isotope analysis we suggest that the late glacial holocene transition may be identified and dated by 13c and 2h tree ring chronologies

environmental change and fluvial activity during the younger dryas in central germany abstract late pleistocene climatically induced environmental changes are reconstructed by applying a multidisciplinary approach on floodplain sediments of small to medium sized catchments in central germany radiocarbon dating pollen analysis and the presence of an accurately dated tephra layer allow the establishment of a reliable chronology the beginning of the younger dryas is marked by a change in fluvial activity that lasts for several hundred years during this period gravels and sands were deposited by a braided river system fluvial systems at this time were predominantly controlled by the climatic conditions of the surrounding uplands where the climatic deterioration led to a lowering of the forest limit and enhanced periglacial slope processes an open pine forest prevailed in the basin areas and no evidence of slope wash and solifluction was found the second part of the younger dryas is characterised by a meandering fluvial system and the deposition of overbank fines the rapid transition from younger dryas to preboreal coincides with an increase in organic deposition

development of texture contrast soils by a combination of bioturbation and translocation abstract soils and weathering profiles in a wide variety of parent materials and environmental settings exhibit coarse over fine vertical textural contrasts where these cannot be attributed to inherited texture contrasts or erosion deposition the most common explanations are based on translocation eluviation illuviation which removes clays from surface layers and deposits them in the subsoil or bioturbation where preferentially fine material is delivered to the surface by organisms from whence erosional winnowing creates a coarse surface layer in some soils of the lower coastal plain of north carolina u s a neither explanation is sufficient to explain the observed texture contrasts a heuristic model based on a combination of translocation of fine material from surface to subsoil and bioturbation driven delivery and recycling of material to the surface can explain the observed vertical textural contrasts the key elements in the model are coastal plain sediments which include some fine material eluviation illuviation by percolating water delivery of additional fine and mixed grain size material to surface by bioturbation making it available for translocation concentration of fine material originally scattered throughout the parent material in a b horizon and maintenance of vertical moisture fluxes by bioturbation the model is supported by morphological evidence of the key mechanisms argillic horizons that are finer than both the surface layers and underlying parent material evidence that argillic horizon formation is not limited by the rate of clay synthesis and the absence of texture contrasts in nearby soils formed from dune sands which lack fines

micromorphology and late glacial holocene genesis of luvisols in mecklenburg vorpommern ne germany abstract in the german soil science literature luvisols formed in weichselian sediments except from the early weichselian are normally regarded as purely holocene soils with the main period of development assumed to have been during the atlantic phase although debated at some length since the 1960s the genesis of the widespread albic luvisols with a simplified ap bw eb ebtb btb g c horizon sequence and developed on the flat and slightly undulating till plains of the north german mecklenburgian stage deglaciation 14 000 bp has yet to be clarified periglacial climate during the late weichselian led to the formation of sand filled wedge shaped structures penetrating bt horizons systematic micromorphologic investigations of soil profiles with sand wedges revealed the occurrence of numerous fragments of rounded limpid clay coatings within periglacial formed lenticular microplates as well as in and at the margins of the sand wedge infillings assuming the younger dryas as the latest possible phase of formation the lenticular microplates and the undisturbed sand wedges postdate clay illuviation undisrupted clay coatings next to fragmented clay coatings prove a subsequent holocene clay illuviation clay illuviation must have occurred at least in warmer phases of the late glacial together with the already accepted pedogenic processes of decalcification organic matter accumulation ahb horizons podzolisation and silicate weathering bwb horizons on sites not influenced by groundwater

the history of soil erosion and fluvial deposits in small catchments of central europe deciphering the long term interaction between humans and the environment a review abstract during the last few decades many case studies focused on the dynamics of fluvial systems in response to hillslope erosion land use impact and climate changes this paper will review the current state of knowledge of the dynamics of past soil erosion and gullying in small catchments

depositional gaps in abitibi greenstone belt stratigraphy a key to exploration for syngenetic mineralization models of greenstone belt development are crucial for exploration allochthonous models predict belts to be a collage of unrelated fragments whereas autochthonous models allow for prediction of syngenetic mineral deposits within specific stratigraphic intervals superior province greenstone belts consist of mainly volcanic units unconformably overlain by largely sedimentary timiskaming style assemblages and field and geochronological data indicate that the abitibi greenstone belt developed autochthonously we describe major revisions to stratigraphy of the abitibi greenstone belt and the implications of an autochthonous development of the volcanic stratigraphy for exploration for syngenetic mineralization the abitibi greenstone belt is subdivided into seven discrete volcanic stratigraphic episodes on the basis of groupings of numerous u pb zircon ages of pre 2750 2750 to 2735 2734 to 2724 2723 to 2720 2719 to 2711 2710 to 2704 and 2704 to 2695 ma we present revised lithotectonic and or stratigraphic nomenclature using these time intervals including 1 isotopic inheritance in younger episodes which indicates that the older episodes 2750 2735 and 2734 2724 ma had greater extent than is presently seen 2 dikes feeding younger volcanic episodes 2706 ma cutting older volcanic units 2734 2724 ma and 3 2710 to 2704 ma mafic to ultramafic sills intruding the 2719 to 2711 ma episode changes to the nomenclature include the identification of pre 2750 ma volcanic episode supracrustal fragments in the northern and southern abitibi greenstone belt and subdivision of the 2719 to 2711 ma 2710 to 2704 ma and 2704 to 2695 ma episodes into lower and upper parts we present the results of this lithostratigraphic subdivision as the first geochronologically constrained stratigraphic and or lithotectonic map of the abitibi greenstone belt many of the volcanic episodes are intercalated with and capped by a relatively thin sedimentary interface zone dominated by chemical sedimentary rocks stratigraphic and geochronological analysis of these zones indicates discontinuous deposition with localized gaps of 2 to 27 m y between volcanic episodes the zones consist of up to 200 m of iron formation chert breccia heterolithic debris flows of volcanic provenance sandstone and or argillite and conglomerate modeling of the time required for deposition of the volcanic units based on rates of magma production in modern arc and plume environments is on the order of 103 to 104 years whereas the time interval between basalt rhyolite cycles is 106 years the sedimentary interface zones are therefore interpreted as condensed sections zones with very low rates of sedimentation in a basinal setting or zones with negligible rates of sedimentation marked by silicification of existing rock types the sedimentary interface zones are therefore considered submarine correlative conformities disconformities or unconformities separating the equivalent of group level stratigraphic and lithotectonic units the unconformity bounded stratigraphic model provides a new regional to deposit scale interpretive model for use in exploration for syngenetic mineralization

structure of the high grade opatica belt and adjacent low grade abitibi subprovince canada an archaean mountain front plutonic gneisses in the archaean opatica belt in canada record crustal scale wsw vergent i e longitudinal high temperature d1 ductile shearing similar structures occur in adjacent greenstone belts but only in narrow amphibolite facies zones near the base metavolcanics in the greenschist facies portions do not record penetrative d1 structures the greenstone belts are interpreted as allochthonous on the gneisses they form the uppermost d1 thrust sheets sse vergent i e approximately transverse d2 thrusting imbricated the opatica belt and formed a large antiform either a culmination or an antiformal stack in the southern opatica the imbricated opatica belt wedged under the northern part of the abitibi subprovince and created a tight syncline with nnw vergent d2 thrusts interpreted as backthrusts on its northern limb the opatica belt abitibi subprovince contact therefore resembles some phanerozic mountain fronts further southwards propagating imbrication of the crust beneath the abitibi subprovince created a s vergent foreland fold and thrust belt in the overlying greenstones high grade opatica gneisses and adjacent low grade abitibi greenstones contain complementary structural patterns and may therefore represent the internal and foreland parts of an archaean mountain belt similar in many respects to phanerozoic examples

timing of the late vistulian weichselian glacial phases in poland abstract the lower vistula region in northern poland is a stratotype area for the vistulian weichselian glaciation and during last glacial maximum lgm the southernmost extension of the scandinavian ice sheet occurred in western poland and in eastern germany reinterpretation of the available geochronological data radiocarbon 36 cl and 10 be ages supplied with new field geological evidence mostly for the late vistulian ice sheet limits and movement directions was focused in three key regions in poland during the late middle vistulian there was one or two ice sheet advances in the lower vistula region the late vistulian maximum ice sheet limit in poland was time transgressive and occurred at 24 19 kyrs bp generally the younger to the east ice sheet limits during the leszno phase occurred at 24 cal 10 be 36 cl kyrs the poznan phase ice sheet limit was dated to 19 10 be 36 cl kyrs and the pomeranian phase ice sheet limit about 16 17 10 be 36 cl kyrs every late vistulian glacial phase in poland was preceded by an ice sheet retreat

sedimentary and pedological processes in the upper pleistocene loess of northern italy the bagaggera sequence abstract the bagaggera sequence consists of two late pleistocene loesses superimposed on the top of middle pleistocene fluviatile sediments the lower loess includes at its base a mousterian archaeological level represented by artifacts dated by tl as 60 500 7500 bp and charcoal from hearths which mainly consists of boreal forest species at the top of the lower loess aurignacian artifacts occur which suggest a tentative date of 35 000 bp the sedimentary and pedological processes which lead to the formation of the sequence were reconstructed by means of mineral and textural analyses and thin section analysis and can be summarized as follows erosion and colluviation of the eemian soil at the base of the sequence during the early wurm isotopic substages 5 a c sedimentation of the lower loess deposits during the first pleniglacial period isotopic stage 4 a large number of coarse pedofeatures in this soil suggests that primary aeolian dust has been redistributed in place or for short distances by syngenetic slight pedogenesis and by water reworking as a result of alternating phases of wet and dry climate an alfisol characterized by strong clay illuviation developed in the lower loess during the hengelo arcy interstadial phase its top was affected by reworking and slight frost activity at the beginning of the second pleniglacial period isotopic stage 2 the upper loess was deposited in a drier environment during the second pleniglacial period isotopic stage 2 water reworking was less effective holocene weathering is expressed by clay illuviation and slight hydromorphism

cambisols developed from cover beds in the pieniny mts southern poland and their mineral composition abstract the occurrence of eutric cambisols in the study area has been usually attributed to specific characteristics of bedrock their basic properties include significant contrasts of ph and the content of carbonates within their profiles analysis of soil texture and the content and lithology of rock fragments indicate discontinuities in the parent material of the upper and lower sections of the investigated profiles the observations have been confirmed by the analysis of xrd diffractograms of unseparated 2 m fraction the properties of the lowermost horizons are naturally related to the characteristics of bedrock while cover beds with a dominance of quartz and a lack of calcite should be recognized as parent material of the upper sections of the profiles the xrd diffractograms of the clay fractions show a continuous uniform process of soil development imposed on the originally heterogeneous profile

depositional frequency of german subfossil oaks climatically and non climatically induced fluctuations in the holocene a highly resolved record of the depositional frequency of subfossil trees since 8263 bc in the valley of the river main is presented different aspects of forest dynamics are explored including depositional anomal ies phases of low or zero departures changes in forest density based on tree growth trend classes gtcs and regeneration using mean lifespan ml data this reveals a number of climatically induced environmental changes that are synchronous with events in the north atlantic region and therefore may reflect a facet of the north atlantic climate system three periods are recognized 1 pre 3500 bc when depositional frequency was dominated by climatic events with notable anomalies at 6200 and 4100 bc 2 between 3500 and 1200 bc when climatically triggered events were enhanced by forest clearances especially marked anomalies occurring around 2700 2300 and 1700 bc and 3 post 1200 bc when the climatic information is obscured by human activities

holocene river activity analysing 14c dated fluvial and colluvial sediments from germany records of fluvial dynamics in response to long term changes of climate and land use impacts are rare therefore cumulative probability functions cpfs of 401 14c ages originating from german rivers and hillslopes were compiled to reconstruct phases of increased geomorphic activity and stability during the holocene an improved analytical method is suggested to normalise cpfs and eliminated the effects of wiggles of the calibration curve and the young age bias nine periods of activity are identified peaking at 7050 6250 5525 3690 2250 1350 820 325 bc and since 875 ad and are compared with climatic palaeohydrological and human impact proxy data until 2250 bc events of geomorphic activity are mainly coupled to wetter and or cooler climatic phases due to growing population and intensive agricultural activities during the bronze age the increased geomorphologic activity between 1300 and 820 bc cannot unequivocally be related to climate since 875 ad the growing population density is considered as the major external forcing differential geomorphic activity of hillslopes and floodplains suggest that the hillslope channel coupling during the holocene is mainly controlled by human impact with a strong increased coupling after 1500 bc

comparison of eruptive and intrusive samples from unzen volcano japan effects of contrasting pressure temperature time paths abstract core samples from the conduit of unzen volcano obtained only 9 years after cessation of the 1991 1995 eruption exhibit important differences in physical characteristics and mineralogy and subtle differences in bulk chemistry from erupted samples these differences in the conduit samples reflect emplacement under a confining pressure where about half of the original magmatic water was retained in the melt phase maintenance at hypersolidus temperature for some unknown but significant time span and subsequent subsolidus hydrothermal alteration in contrast magma that extruded as lava underwent decompression to 1 atm with nearly complete loss of magmatic water and cooling at a sufficiently rapid rate to produce glass the resulting hypabyssal texture of the conduit samples while clearly distinct from eruptive rocks is also distinct from plutonic suites given the already low temperature of the conduit less than 200 c nakada s uto k yoshimoto m eichelberger j c shimizu h 2005 scientific results of conduit drilling in the unzen scientific drilling project usdp sci drill 1 18 22 when it was sampled by drilling this texture must have developed within a decade and perhaps within a much shorter time after emplacement the fact that all trace element concentrations of the conduit and the last emplaced lava of the spine 1300 m above it are identical to within analytical uncertainty provides strong evidence that both were produced during the same eruption sequence changes in conduit magma that occurred between emplacement and cooling to the solidus were collapse of vesicles from less than or equal to the equilibrium value of about 50 vol to about 0 1 vol continued resorption of quartz and reaction of biotite phenocrysts due to heating of magma prior to ascent by intruding mafic magma breakdown of hornblende and micro crystallization of rhyolitic melt to feldspar and quartz subsolidus changes were deposition of calcite and pyrite growth of sericite in anorthite rich zones of plagioclase and development of montmorillonite as an alteration product significant changes in bulk composition were depletion of mg fe and na and enrichment in c and s these changes were due mainly to the breakdown of hornblende and plagioclase and addition of carbonate and pyrite respectively the identical concentrations of rees in the conduit and surface lava are consistent with low water to rock ratios during alteration this suggests to us that despite convective hydrothermal removal of heat from the conduit chemical open system effects were limited to early loss of magmatic water and later addition of magmatic co2 and so2 and or h2s streaming up the conduit from deeper levels