matrix association effects on hydrodynamic sorting and degradation of terrestrial organic matter during cross shelf transport in the laptev and east siberian shelf seas this study seeks an improved understanding of how matrix association affects the redistribution and degradation of terrigenous organic carbon terroc during cross shelf transport in the siberian m

long term hydroclimatic variability in monsoon shadow zone of western himalaya india tree ring width data of himalayan cedar cedrus deodara roxb g don from 11 homogeneous moisture stressed sites in the monsoon shadow zone of the western himalaya were used to develop a mean chronology extending back to ad 1353 the chronology developed using regional curve standardization method is the first from the himalayan region of india showing centennial scale variations the calibration of ring width chronology with instrumental precipitation data available from stations close to the tree ring sampling sites showed strong direct relationship with march april may june mamj precipitation this strong relationship was used to supplement the instrumental precipitation data back to ad 1410 the precipitation reconstruction showed extended period of drought in fifteenth and sixteenth centuries increasingly pluvial conditions were recorded since eighteenth century with the highest precipitation in the early part of the nineteenth century the decreasing trend in reconstructed precipitation in the last decade of the twentieth century consistent with the instrumental records is associated with the decreasing trend in frequency of western disturbances mamj precipitation over the monsoon shadow zone in the western himalaya is directly associated with the north atlantic oscillation nao and nino3 sst index of el nino southern oscillation enso the leading modes of climate variability influencing climate over large parts of the northern hemisphere however the relationship between enso and mamj precipitation collapsed completely during 1930 1960 the breakdown in this relationship is associated with the warm phase of atlantic multidecadal oscillation amo a spectral analysis of reconstructed mamj precipitation indicates frequencies in the range of the variability associated with modes of nao enso and amo

african rift tectonics and sedimentation an introduction rifts are one of the most spectacular features of global morphology within oceans they separate plates as new oceanic crust is created within continents they may form deep valleys such as the rhine graben within which runs one of the world s busiest waterways they are often floored by deep lakes such as lake baikal the deepest lake in the world today whose floor lies 1700 m below the surface of the lake ancient rifts are the sites of petroleum accumulations beneath the margins of the atlantic in the north sea and in china of coals and oil shales and of minerals including phosphates barite cu pb zn sulphides and uranium robbins 1983 of all the world s rifts none can match in scale and diversity the great rift system which runs for over 7000 km and includes the east african rift system and its extension through the red sea into the dead sea to form a unique feature of global geology its study is important not only for what it can tell about the nature and origin of present day rifts the thermal magmatic and tectonic processes which gave rise to them climatic changes and sedimentary particularly lacustrine and volcaniclastic processes it is also essential for the understanding of the processes which formed passive continental margins all of which are underlain by rifted sedimentary basins and failed rifts whether they formed within continents or at the junction of continents and oceans early workers on rifts were impressed by the wide valleys 40 50 km across filled by young alluvial and lacustrine sediments and bordered by steep escarpments rising in some cases a few hundred metres in others up to 3 4000 m above the valley floor many rifts are the sites of volcanic activity sometimes of rather unusual composition these unusual volcanic source rocks may in turn be the cause of peculiar lake water chemistries many rift lakes containing unique suites of evaporitic minerals although at one time some people considered rifts to have been formed by compression rampvalley hypothesis discussion today revolves principally around the extent to which rift valleys are extensional features or are the result of oblique slip movements between two laterally moving blocks there is no doubt now that some rift valleys are the result of strike slip movement the dead sea gulf of elat rift lies along a lineament that separates two lithospheric plates and as arabia moves northwards relative to the palestinian mediterranean block and faults curve or sidestep each other extensional pull apart basins are formed such as the dead sea whose surface lies further below sea level than any other place in the world a feature of these strike slip rift valleys is that the extensional valleys pass along the rift into mountainous zones of compression and uplift rapid erosion from these mountains leads to substantial sediment supply for the basins from within the fault system itself ancient strike slip rift basins are therefore characterized by very thick rapidly accumulated basin fills with areas of contemporaneous compressional tectonics and unconformities not far away rift valley basins that are extensional features on a regional scale tend to sink rather more slowly have less sediment entering them and show no evidence of synchronous compressional tectonics in their neighbourhood cross sections through them show normal faulting probably listric in form the main controversy with regard to extensional rift valleys is whether magmatic activity in rifts reflects an underlying heat source such as a convection plume in the mantle or hot spot the rifting then being the consequence of expansion and uplift brought about by thermal activity or whether the magmatic activity is merely the result of regional or local extensional stresses which have passively allowed magma to come to the surface some rifts that penetrate continents are clearly failed rifts or aulacogens that began as one arm of a triple junction as ocean floor spreading developed along two arms one arm was left as a failed rift in the sense that new oceanic crust was not created perhaps the best known is the benuc trough within which the niger delta developed however the northern viking graben of the north sea has been claimed to be one whiteman et al 1975 and so has that part of the east african rift known as the afar triangle where thc red sea and the gulf of aden rifts successfully drifted whilst the afar triangle failed molnar tapponnier 1975 have argued that other rifts are the result of continental collision in particular that the impact of india with asia caused not only major lateral displacement along

formation infill and dissection of a latest pleistocene landslide dammed reservoir betic cordillera southern spain upstream and downstream geomorphological and sedimentological evidence abstract a slope collapse in a narrow mountainous valley led to the formation of a latest pleistocene 14 500 cal bp lake dammed behind this mass movement deposit in the betic cordillera se spain the lithostructural conditions of the carbonate bedrock a warm and more humid period at the end of the last glaciation bolling interstadial and its location very close to a seismic mountain front provide the ideal context for the destabilization and failure of bedrock and the subsequent formation of this ephemeral mountain basin it was filled in 260 years estimated specific sediment yield ssy is at least two orders lower than ssy nowadays in se spain the calculated value of 81 t km2 y is similar to calculated values from artificial reservoirs in more humid and temperate drainage areas such as in central europe geomorphological and sedimentological features of the siltation of the landslide dammed reservoir have been preserved close to the betic cordillera mountain front the reservoir fill consists of over 30 m of lacustrine and alluvial deposits the lake created upstream of the landslide dam was silted by mainly terrigenous gilbert type delta gravels and turbiditic sands and mixed terrigenous bioclastic sedimentation horizontally laminated carbonate mudstones after the lake was silted a meandering river caused linear erosion over the natural dam and deeply dissected the lacustrine deposits above the river s pre landslide profile this process has allowed the study of the well preserved internal structure of the natural reservoir and identification of the stages in the construction and degradation of a semi closed basin the stages involved in the evolution of the landslide dammed reservoir may provide insights into studying the development of other closed or semi closed basins such as mountain basins or artificial dams

accelerated thawing of subarctic peatland permafrost over the last 50 years 1 in this study we provide a quantification of the main patterns of change of a subarctic peatland caused by permafrost decay monitored between 1957 and 2003 up thrusting of the peatland surface due to permafrost aggradation during the little ice age resulted in the formation of an extensive peat plateau that gradually fragmented into residual palsas from the 19th century to the present only about 18 of the original surface occupied by permafrost was thawed in 1957 whereas only 13 was still surviving in 2003 rapid permafrost melting over the last 50 years caused the concurrent formation of thermokarst ponds and fen bog vegetation with rapid peat accumulation through natural successional processes of terrestrialization the main climatic driver for accelerated permafrost thawing was snow precipitation which increased from 1957 to present while annual and seasonal temperatures remained relatively stable until about the mid 1990s when annual temperature rose well above the mean contrary to current expectations the melting of permafrost caused by recent climate change does not transform the peatland to a carbon source ecosystem as rapid terrestrialization exacerbates carbon sink conditions and tends to balance the local carbon budget

spatial distribution of sediment storage types and quantification of valley fill deposits in an alpine basin reintal bavarian alps germany spatial patterns of sediment storage types and associated volumes using a novel approach for quantifying valley fill deposits are presented for a small alpine catchment 17 km 2 in the bavarian alps the different sediment storage types were analysed with respect to geomorphic coupling and sediment flux activity the dominant landforms in the valley in terms of surface area were found to be talus slopes sheets and cones followed by rockfall deposits and alluvial fans and plains more than two thirds of the talus slopes are relict landforms completely decoupled from the geomorphic system notable sediment transport is limited to avalanche tracks debris flows and along floodplains sediment volumes were calculated using a combination of polynomial functions of cross sections seismic refraction and gis modelling a total of 66 seismic refraction profiles were carried out throughout the valley for a more precise determination of sediment thicknesses and to check the bedrock data generated from geomorphometric analysis we calculated the overall sediment volume of the valley fill deposits to be 0 07 km 3 this corresponds to a mean sediment thickness of 23 3 m the seismic refraction data showed that large floodplains and sedimentation areas which have been developed through damming effects from large rockfalls are in general characterised by shallow sediment thicknesses 20 m by contrast the thickness of several talus slopes is more than twice as much for some locations e g narrow sections of valley the polynomial generated cross sections resulted in overestimations of up to one order of magnitude whereas in sections with a moderate valley shape the modelled cross sections are in good accordance with the obtained seismic data for the quantification of valley fill deposits a combined application of bedrock data derived from polynomials and geophysical prospecting is highly recommended d 2003 elsevier b v all rights reserved

evolution of the methane cycle in ace lake antarctica during the holocene response of methanogens and methanotrophs to environmental change abstract post glacial ace lake vestfold hills antarctica which was initially a freshwater lake and then an open marine system is currently a meromictic basin with anoxic sulfidic and methane saturated bottom waters lipid and 16s ribosomal rna gene stratigraphy of up to 10 400 year old sediment core samples from the lake revealed that these environmentally induced chemical and physical changes caused clear shifts in the species composition of archaea and aerobic methanotrophic bacteria the combined presence of lipids specific for methanogenic archaea and molecular remains of aerobic methanotrophic bacteria 13c depleted 8 14 sterols and 16s rrna genes revealed that an active methane cycle occurred in ace lake during the last 3000 calendar years and that the extant methanotrophs were most likely introduced when it became a marine inlet 9400 y bp rdna sequences of known methanogens were only recovered from the oldest sediments deposited during the freshwater phase the latter sequences showed 100 sequence similarity with methanosarcinales species from freshwater environments and were the source of sn 2 and sn3 hydroxyarchaeols archaeal phylotypes related to uncultivated archaea associated with various marine environments were recovered from the present day anoxic water column and sediments deposited during the meromictic and marine period

sequence stratigraphy in lacustrine basins a model for part of the green river formation eocene southwest uinta basin utah u s a abstract in the middle green river formation of central nine mile canyon uinta basin utah several lacustrine dominated intervals 10 m thick comprise aggradational carbonate parasequence sets and a progradational clastic parasequence maximum flooding surfaces are best identified within profundal oil shale that caps some of the clastic parasequences these lacustrine transgressive systems tracts therefore exhibit parasequence stacking patterns unlike typical marine sequences two types of sequence boundary are identified type a sequence boundaries display evidence for a basinward shift in facies across a regionally mappable surface that is an angular or rarely parallel unconformity and they typically juxtapose amalgamated braided fluvial channel sandstone late lowstand systems tract onto the profundal oil shale they also bound depositional sequences that show a distinct asymmetry being dominated by transgressive systems tracts 5 80 m thick highstand systems tracts are less than 4 m thick and may be removed completely by erosion on overlying sequence boundaries other surfaces satisfy only some of the standard criteria of sequence boundaries and are termed type b sequence boundaries type a sequence boundaries mark pronounced base level falls following times when the uinta lake had merged with a lake in an adjacent basin to form a much deeper lake such merging permitted the establishment of a new threshold at higher elevation following lake level balancing type b sequence boundaries are interpreted as marking base level falls from a barely merged lake or a lake that had an outflow over a 200 m stratigraphic thickness type a sequence boundaries are more common upsection indicating that with time a pluvial climate became more pronounced or that the adjacent lake was more easily filled type a sequence boundaries also become angular rather than parallel unconformities upsection suggesting increased tilting of the basin margin over time

formation of internally drained contractional basins by aridity limited bedrock incision 1 low internal relief aridity and internal drainage characterize the puna altiplano plateau and the tibetan plateau and the tarim basin structurally these areas are reverse fault bounded terrains with intervening wedge top basins that store thick accumulations of sediment for millions of years orographic barriers along the margins of these basins are oriented normal to moisture bearing winds resulting in regional aridity the combination of this aridity rapid shortening and uplift rates and resistant exposed lithologies coincides with the location of these internally drained basins we hypothesize that these large internally drained areas persist indefinitely when uplift overwhelms the fluvial systems and defeats the channel network to test this hypothesis we developed models of channel defeat to examine the threshold conditions required to fragment the channel network the results of these models suggest that low erodibility rocks moderate to high uplift rates and low precipitation favor defeat of orogen traversing channels most coupled tectonic landscape development models prevent the development of internal drainage and so may overestimate the voracity of erosion in regimes that favor internal drainage profoundly influencing predicted orogenic growth patterns

millennial scale variability of denudation rates for the last 15 kyr inferred from the detrital 10be record of lake stappitz in the hohe tauern massif austrian alps reconstructing paleo denudation rates over holocene timescales in an alpine catchment provides a unique opportunity to isolate the climatic forcing of denudation from other tectonic or anthropogenic effects cosmogenic 10be on two sediment cores from lake stappitz austrian alps were measured yielding a 15 kyr long catchment averaged denudation record of the upstream seebach valley the persistence of a lake at the outlet of the valley fixed the baselevel and the high mean elevation minimizes anthropogenic impacts the 10be record indicates a decrease in the proportion of paraglacial sediments from 15 to 7 kyr cal bp after which the 10be concentrations are considered to reflect hillslope erosion and thus can be converted to denudation rates these ones significantly fluctuated over this time period lower hillslope erosion rates of ca 0 4 mm year dated between 5 and 7 kyr cal bp correlate with a stable climate sparse flooding events and elevated temperatures that favoured the widespread growth of st

constraints on water reservoir lifetimes from catchment wide 10be erosion rates a case study from western turkey the functionality and retention capacity of water reservoirs is generally impaired by upstream erosion and reservoir sedimentation making a reliable assessment of erosion indispensable to estimate reservoir lifetimes widely used river gauging methods may underestimate sediment yield because they do not record rare high magnitude events and may underestimate bedload transport hence reservoir lifetimes calculated from short term erosion rates should be regarded as maximum values we propose that erosion rates from cosmogenic 10be which commonly integrate over hundreds to thousands of years are useful to complement short term sediment yield estimates and should be employed to estimate minimum reservoir lifetimes here we present 10be erosion rates for the drainage basins of six water reservoirs in western turkey which are located in a tectonically active region with easily erodible bedrock our 10be erosion rates for these catchments are high ranging from 170 to 1040 t km2 yr when linked to reservoir volumes they yield minimum reservoir lifetimes between 25 5 and 1650 360 years until complete filling with four reservoirs having minimum lifespans of 110 years in a neighboring region with more resistant bedrock and less tectonic activity we obtain much lower catchment wide 10be erosion rates of 33 to 95 t km2 yr illustrating that differences in lithology and tectonic boundary conditions can cause substantial variations in erosion even at a spatial scale of only 50 km in conclusion we suggest that both short term sediment yield estimates and 10be erosion rates should be employed to predict the lifetimes of reservoirs

influence of holocene permafrost aggradation and thaw on the paleoecology and carbon storage of a peatland complex in northwestern canada permafrost in peatlands strongly influences ecosystem characteristics including vegetation composition hydrological functions and carbon cycling large amounts of organic carbon are stored in pe

quantification of soil erosion rates related to ancient maya deforestation we used seismic and sediment core data to quantify soil erosion rates for the past 6000 yr in the closed catchment of lake salpeten in the tropical lowlands of northern guatemala the region was affected by ancient maya land use from before ca 1000 b c to a d 900 this period of human impact coincided with deposition in the lake of a detrital unit maya clay as much as 7 m thick that contrasts sharply with the relatively organic rich gyttja deposited both before and after maya occupation of the watershed the greatest soil loss with mean sustained values of 1000 t km2yr 1 occurred in the middle and late preclassic periods 700 b c to a d 250 associated with relatively low maya population densities soil erosion slowed during the period of maximum population density in the late classic period a d 550 830 indicating a decoupling between human population density and soil erosion rate the most rapid soil loss occurred early during initial land clearance suggesting that even low numbers of people can have profound impacts on lowland tropical karst landscapes

geochemistry of great salt lake utah ii pleistocene holocene evolution sedimentologic and biostratigraphic evidence is used to develop a geochemical model for great salt lake utah extending back some 30 000 yrs b p hydrologie conditions as defined by the water budget equation are characterized by a lake initially at a low saline stage rising by about 17 000 yrs b p to fresh water basin full conditions bonneville level and then after about 15 000 yrs b p dropping rapidly to a saline stage again as exemplified by the present situation inflow composition has changed through time in response to the hydrologie history during fresh water periods high discharge inflow is dominated by calcium bicarbonate type river waters during saline stages low discharge nacl rich hydrothermal springs are significant solute sources this evolution in lake composition to nacl domination is illustrated by the massive mirabilite deposition free of halite following the rapid drawdown until about 8 000 years ago while historic droughts have yielded principally halite hydrologic history can be combined with inferred inflow composition to derive concentration curves with time for each major solute in the lake calcium concentrations before the drawdown were controlled by calcite solubility and afterwards by aragonite significant amounts of solutes are removed from the lake by diffusion into the sediments na cl and so42 are also involved in salt precipitation by including pore fluid data a surprisingly good fit has been obtained between solute input over the time period considered and the amounts actually found in lake brines pore fluids salt beds and sediments excess amounts are present for calcium carbonate and silica indicating detrital input

dendroclimatic reconstruction of april may temperature fluctuations in the western himalaya of india since a d 1698 abstract ring width chronologies of himalayan cedar cedrus deodara d don g don himalayan pine pinus wallichianaa b jackson and himalayan spruce picea smithiana wall boiss from the western himalayan region india have been used to reconstruct mean april may temperature back to a d 1698 the reconstruction correlates significantly with the average april may instrumental temperature record r 0 62 1876 1988 and is characterized by annual to multiyear fluctuations the most striking feature of the present reconstruction is the absence of any warming trend in the 20th century relationships between the mean april may temperature for the western himalayan region indian summer monsoon rainfall and southern oscillation index indicate that the tree ring chronologies as surrogate temperature records will provide valuable data for climate change studies with regional and global perspectives

space time variability of denudation rates at the catchment and hillslope scales on the tyrrhenian side of central italy studies on denudation rates can provide insight into the influence of climate change tectonics and human activities on landscape evolution research performed in central italy has shown considerable spatial variability of denudation rates in the major river basins these studies have focused mainly on the tyrrhenian side of the italian peninsula where plio pleistocene marine deposits filling nw se elongated sedimentary basins have been uplifted during the quaternary up to several hundreds of meters above present sea level small sub catchments developed on clays are affected by sharp and or rounded edged badlands i e calanchi and biancane representing denudation hot spots in the present day morphoclimatic framework in this paper we analyze the relationships between indirectly estimated denudation rates at the catchment scale and field monitoring data at the hillslope scale we attempt to better understand and quantify all hillslope processes that contribute to seasonal variability of denudation to help with predicting the net input from hot spots to the overall estimated sediment yield at the basin outlets at the hillslope scale we discuss in particular the variability of denudation rates at calanchi and biancane badlands as a function of their different morphoevolution

methane oxidation following submarine permafrost degradation measurements from a central laptev sea shelf borehole submarine permafrost degradation has been invoked as a cause for recent observations of methane emissions from the seabed to the water column and atmosphere of the east siberian shelf sediment drilled 52 m down from the sea ice in buor khaya bay central laptev sea revealed unfrozen sediment overlying ice bonded permafrost methane concentrations in the overlying unfrozen sediment were low mean 20 m but higher in the underlying ice bonded submarine permafrost mean 380 m in contrast sulfate concentrations were substantially higher in the unfrozen sediment mean 2 5 mm than in the underlying submarine permafrost mean 0 1 mm using deduced permafrost degradation rates we calculate potential mean methane efflux from degrading permafrost of 120 mg m 2 yr 1 at this site however a drop of methane concentrations from 190 m to 19 m and a concomitant increase of methane 13c from 63 to 35 directly above the ice bonded permafrost suggest that methane is effectively oxidized within the overlying unfrozen sediment before it reaches the water column high rates of methane ebullition into the water column observed elsewhere are thus unlikely to have ice bonded permafrost as their source

sediment yield in europe spatial patterns and scale dependency abstract our understanding about the regional variation of sediment yield sy in europe and its scale dependency currently relies on a limited number of data for mainly larger river systems sy is the integrated result of all erosion and sediment transporting processes operating in a catchment and is therefore of high value for environmental studies and monitoring purposes most global assessments of sy consider catchment area a climate and topography as the main explanatory variables however it is still unclear if these factors also control regional variations of sy within europe this paper aims at bridging this gap therefore we i present a large database of sy values which was constructed through an extensive literature review ii describe the spatial patterns of sy across europe and iii explore its relation with a climate and topography in total sediment yield data from 1794 different locations throughout europe were collected 507 reservoirs and 1287 gauging stations representing a minimum of 29 203 catchment year data only sy data measured at gauging stations or derived from reservoir siltation rates over a period of a minimum of one year were included in the database this database comprises a large range of catchment areas a i e from small upland catchments 0 01 km to major european river basins 1 360 000 km an overview of the collected sy data is provided and sources of uncertainty on the available data are discussed despite potentially large uncertainties on several of the individual sy values analysis of this database indicates clear spatial patterns of sy in europe the temperate and relatively flat regions of western northern and central europe generally have relatively low sy values with ca 50 of the sy 40 t km 2 yr 1 and ca 80 of the data 2 yr 1 while mediterranean and mountainous regions generally have higher sy values with around 85 of the sy data 40 t km 2 yr 1 and more than 50 of the data 200 t km 2 yr 1 these differences are attributed to a combination of factors such as differences in climate topography lithology and land use although larger differences in sy were found between the climatic regions than between topographic zones it is currently difficult to identify the individual importance of the various controlling factors of sy sy a relationships were calculated for the entire dataset and for subgroups stratified according to the measurement method gauging stations or reservoir surveys range of the catchment area climatic region topographic zone of the river outlet and major european river system although typically a negative relationship between sy and a is expected due to a decrease in topsoil erosion rates on more gentle slopes and an increase in sediment deposition with an increase in catchment size this relationship was found to be generally very weak and subject to a lot of scatter furthermore results illustrate important differences in scale dependency whereas a weak but significant negative trend is generally observed for the temperate and relatively flat regions no significant or even positive trends were observed in mountain regions and mediterranean europe when only larger river catchments i e 100 km and especially 10 000 km are considered catchment area exerted a larger control on sy these findings confirm previous studies and indicate that the relationship between sy spatial scale and other controlling factors is often complex and non linear

preferential burial of permafrost derived organic carbon in siberian arctic shelf waters the rapidly changing east siberian arctic shelf esas receives large amounts of terrestrial organic carbon oc from coastal erosion and russian arctic rivers climate warming increases thawing of coastal ice complex deposits icd and can change both the amount of released oc as well as its propensity to be converted to greenhouse gases fueling further global warming or to be buried in coastal sediments this study aimed to unravel the susceptibility to degradation and transport and dispersal patterns of oc delivered to the esas bulk and molecular radiocarbon analyses on surface particulate matter pm sinking pm and underlying surface sediments illustrate the active release of old oc from coastal permafrost molecular tracers for recalcitrant soil oc showed ages of 3 4 13 14c ky in surface pm and 5 5 18 14c ky in surface sediments the age difference of these markers between surface pm and surface sediments is larger i in regions with low oc accumulation rates suggesting a weaker exchange between water column and sediments and ii with increasing distance from the lena river suggesting preferential settling of fluvially derived old oc nearshore a dual carbon end member mixing model showed that i contemporary terrestrial oc is dispersed mainly by horizontal transport while being subject to active degradation ii marine oc is most affected by vertical transport and also actively degraded in the water column and iii oc from icd settles rapidly and dominates surface sediments preferential burial of icd oc released into esas coastal waters might therefore lower the suggested carbon cycle climate feedback from thawing icd permafrost

from gullies to mountain belts a review of sediment budgets at various scales this paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research sediments are a product of mass dispersal at the earth surface and take part in global cycles sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface this involves fundamental questions about the interplay of uplift climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion reservoir siltation and coastal protection first after introducing basic concepts relevant scales and methodologies the different components of quaternary routing systems from erosion in headwaters river systems glacial and paraglacial systems lakes deltas estuaries coasts shelves epicontinental seas and deep sea fans are discussed in terms of their sediment budget most suitable are sedimentologically closed or semi closed depositional environments e g alluvial fans lakes deltas and deep sea fans in a second step the dynamics of passive active and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings in terms of sedimentary basin types rifts intracontinental and epicontinental settings are preferred objects of sediment budgets because of their persistence and relatively simple overall sedimentary architecture however closing basins such as foreland forearc retroarc piggy back and wedge top basins may provide excellent snapshots of orogenic sediment fluxes in a third step the large long lived routing systems of the amazon the ganges brahmaputra and the rhine are reviewed for each system estimates of either sediment volumes mass or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the late glacial maximum as well as the cenozoic following lessons can be taken from these case studies i depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems ii the response times of these large systems are within the milankovich time interval thus lower than predicted from diffusion models iii cyclic routing of sediments in continental basins is much more dominated by climate human control than by eustacy and iv at long time scales ultimate sinks win over intermittent storage it is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles this includes i to better determine response times of large routing systems by linking quaternary with cenozoic sediment budgets and continental with marine sub systems ii to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems iii to study sediment partitioning at the basin scale iv to reconcile continental supply dominated sequence stratigraphy with the eustatic dominated marine concept and iv to account for non actualism of ancient systems with respect to their erosion and transport mode in particular during glaciations and pronounced arid intervals glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins thus challenging the principle of mass conservation

a two step expansion of the dinocyst lingulodinium machaerophorum in the caspian sea the role of changing environment dinoflagellate cyst assemblages were analysed in four short sediment cores collected in the south basin of the caspian sea for assessing environmental changes over the last few millennia two of these cores were dated by radionuclides the sedimentation rate of one of them was very high in the order of 20 mm per year the interpretation of the four sequences is supported by a collection of 27 lagoonal or marine surface sediment samples a sharp increase in the concentration of the dinocyst occurs after 1967 especially owing to lingulodinium machaerophorum considering nine other cores covering parts or the whole of holocene it became clear that this species started to develop in the caspian sea only during the last three millennia by analysing instrumental data and collating existing reconstructions of sea level changes over the last decades we show that the main forcing for the recent increase of l machaerophorum percentages and concentration is global climate change especially sea surface temperature increase sea level fluctuations likely only have a minor impact we argue that the recent increase in l machaerophorum indicates that the caspian sea clearly is in the anthropocene

permafrost carbon stock and decomposability of a globally significant carbon pool 1 the magnitude of future co2 induced climate warming is difficult to predict because of uncertainties in the role of ecosystems and oceans as co2 sources and sinks siberia has extensive areas 1 106 km2 of deep up to 90 m deposits of organic rich frozen loess wind blown silt that accumulated during the pleistocene but have not been considered in most global carbon c inventories similar deposits occur less extensively in alaska recent warming at high latitudes causes this permafrost permanently frozen ground to thaw raising questions about the fate of c in thawing permafrost here we show that siberian loess permafrost contains a large organic c pool 450 gt more than half the quantity in the current atmosphere that decomposes quickly when thawed and could act as a positive feedback to climate warming

post collisional sediment budget history of the alps tectonic versus climatic control based on the sediment budget of the eastern swiss and western alps since the oligocene the regional tectonic evolution has been identified as the dominant factor it is superimposed on the influence of both regional and global climate change and global sea level change during late pliocene and pleistocene times climate became the dominant factor because of cyclic glaciations the early post collisional history of the alps is characterized by a doubling of sediment discharge rates around the rupelian chattian boundary this increase is attributed to isostatic re adjustment either after large scale thermal reorganization of the lithosphere related to slab break off or to crustal thickening as continental crust became subducted from middle oligocene to late miocene times the overall trend of sediment discharge rates in the entire alps was modified only during relatively short lived phases these are characterized by an increase in aquitanian ca 23 21 ma and late burdigalian times ca 18 16 4 ma and a decrease in early to middle burdigalian 21 19 ma and langhian to serravalian times 16 4 12 ma an important still ongoing period of uplift reflected by rapidly increasing sediment discharge rates started in latest miocene times in the swiss and western alps and affected the eastern alps some 2 million years later the reason for this uplift is not clear but deep seated lithospheric processes appear to be likely

paleoenvironmental and paleoclimatic records from permafrost deposits in the arctic region of northern siberia ice complexes extremely ice rich permafrost deposits with large ice wedges are widely distributed in the arctic region of northeast siberia they present excellent archives for the reconstruction of late quaternary paleoenvironmental conditions in nonglaciated areas in 1998 1999 and 2000 russian and german scientists worked together on the bykovsky peninsula southeast of the lena delta in order to investigate the ice complex and its associated sediments intensive cryolithological and sedimentological studies radiocarbon age determinations paleobotanical studies micropaleontological investigations studies of mammal and insect fossils and stable isotope analyses of ground ice were performed radiocarbon data have been obtained from the entire exposed sequence coveringapproximately the last 60 000 years the results indicate that compared with modern time the investig ated ice complex sequence was formed duringtwo cooler and more arid stages of the late pleistocene with relatively uniform environmental conditions separated by a stage with environmental variations and more intensive soil formation caused by climate amelioration the late pleistocene environmental changes were not as strong as those occurring during the pleistocene holocene transition where a sharp break is evident r 2002 elsevier science ltd and inqua all rights reserved

soil organic carbon pools in the northern circumpolar permafrost region of all soils in the northern permafrost region is approximately 18 782 10 3 km 2 o r approximately 16 of the global soil area in the northern permafrost region organic soils peatlands and cryoturbated permafrost affected mineral soils have the highest mean soil organic carbon contents 32 2 69 6 kg m 2 here we report a new estimate of the carbon pools in soils of the northern permafrost region including deeper layers and pools not accounted for in previous analyses carbon pools were estimated to be 191 29 pg for the 0 30 cm depth 495 80 pg for the 0 100 cm depth and 1024 00 pg for the 0 300 cm depth our estimate for the first meter of soil alone is about double that reported for this region in previous analyses carbon pools in layers deeper than 300 cm were estimated to be 407 pg in yedoma deposits and 241 pg in deltaic deposits in total the northern permafrost region contains approximately 1672 pg of organic carbon of which approximately 1466 pg or 88 occurs in perennially frozen soils and deposits this 1672 pg of organic carbon would account for approximately 50 of the estimated global belowground organic carbon pool

determination of recent deposition rates in lake constance with radioisotopic methods sedimentation rates were determined with the 210pb method in eight sediment cores from lake constance the rate of deposition in the main basin obersee varies from about 0 06 g cm 2 y 1 in the central part to 0 13 g cm 2 y 1 in the eastern part of the lake and then increases rapidly towards the rhine delta in the central lake area the rate of deposition has been approximately constant since 1900 and dating with the 210pb method is in good agreement with sedimentological observations in the konstanzer trichter area the deposition rate has been increasing since about 1955 as a result of eutrophication and subsequent high carbonate production dating with 137cs is fairly accurate for sediments deposited at a high rate but is questionable for slowly accumulating ones a positive correlation of 210pb fluxes and sedimentation rates indicates that 210pb flux into sediments follows the distribution pattern of solids 210pb profiles in four sediment cores interpreted in terms of a constant flux model display synchronous fluctuations of the sedimentation rate however their relation to long range particulate input variations remains to be proved sedimentation rates determined with the 210pb method were used to calculate recent nutrient and heavy metal fluxes anthropogenic fluxes of zn and pb are in the same range of magnitude as in other polluted areas in europe and america

tracking sediment provenance and erosional evolution of the western greater caucasus this article investigates landscape characteristics and sediment composition in the western greater caucasus by using multiple methods at different timescales our ultimate goal is to compare short term versus long term trends in erosional processes and to reconstruct spatio temporal changes in sediment fluxes as controlled by partitioning of crustal shortening and rock uplift in the orogenic belt areas of active recent uplift are assessed by quantitative geomorphological techniques digital elevation model dem analysis of stream profiles and their deviation from equilibrium and compared with regions of rapid exhumation over longer time intervals as previously determined by fission track and cosmogenic nuclide analyses complementary information from petrographic and heavy mineral analyses of modern sands and ancient sandstones is used to evaluate erosion integrated throughout the history of the orogen river catchments displaying the highest relief as shown by channel steepness indices correspond with the areas of most rapid exhumation as outlined by thermochronological data the region of high stream gradients is spatially associated with the highest topography around mount elbrus where sedimentary cover strata have long been completely eroded and river sediments display the highest metamorphic indices and generally high heavy mineral concentrations this study reinforces the suggestion that the bedrock channel network can reveal much of the evolution of tectonically active landscapes and implies that the controls on channel gradient ultimately dictate the topography and the relief along the greater caucasus our integrated datasets obtained during a decade of continuing research display a general agreement and regularity of erosion patterns through time and consistently indicate westward decreasing rates of erosional unroofing from the central part of the range to the black sea 2014 john wiley sons ltd

the himalaya bengal fan denudation accumulation system during the past 20 ma mass balances for both denudation in the himalayas and sediment accumulation in the subhimalayan basins including the bengal deep sea fan but excluding the indus fan yield 7 1 106 km3 and 7 4 106 km3 s 20 rock of 2 75 g cm3 density respectively for the past 20 million years coarsening and increased sediment accumulation rates in the foreland basin and in the bengal foredeep indicate accentuated tectonic activity and unroofing in the himalayas since that time the sediment volume includes 1 106 km3 of neogene bengal fan sediment that was lost via the nicobar fan to the sunda accretionary wedge in addition the indian peninsular rivers contributed about c 0 6 106 km3 of solid load to the basins average denudation during the past 20 m y as derived from geothermobarometric data and restored cross sections occurred most rapidly along the high himalayan crystalline chain vertical unroofing c 1000 m m y northward lateral retreat of southern himalayan slope exposed to monsoonal rain

streamflow variability for the aksu river on the southern slopes of the tien shan inferred from tree ring records gauged river flow records from china generally span only a few decades which hampers the detection of long term decadal to centennial scale cycles and trends in streamflow variability new and updated tree ring chronologies help reconstructed the water year october september streamflow for the aksu river which is an important river at the edge of the taklimakan desert that drains into the tarim basin the reconstruction dates back to 1692 and has an adjusted r 2 of 0 61 1957 2006 based on frequency intensity and duration of droughts and pluvial events the lowest streamflows occurred in the 1920s since then streamflow has continuously increased and was exceptionally rapidly after the 1960s until today the start and end of the 20th century to the present were the highest streamflow periods the mid 20th century was the longest and driest period over the past 300 yr the reconstructed streamflow series has a strong positive correlation with the north atlantic oscillation index changes in mid latitude circulation patterns influencing precipitation may have indirectly resulted in streamflow variations along the aksu river over the past 300 yr the rapid increase and the exceptional streamflows of the 1960s are likely linked with global warming and mid latitude atmospheric circulation changes c 2016 university of washington published by elsevier inc all rights reserved

mechanical analysis of a natural example of onland gravity gliding the role of river incision and deposition gravity gliding implies rigid translation of a body down a slope where displacements are parallel to a tilted detachment plane although large scale gravity gliding is commonly observed offshore under conditions of high fluid overpressure and abundant upslope sedimentary supply its occurrence on land is debated we investigate the mechanical feasibility of such a process as well as the role of fluvial incision and sedimentation down the slope in the initiation of the gliding we use a two dimensional 2 d finite element model combined with a 2 d failure analysis approach the numerical models simulate the deformation and provide quantitative estimates of the failure criteria at the head and toe of the overburden analytical solutions approximate the numerical results by taking into account the fluvial incision and sedimentation the internal friction angle and the thickness and length of the overburden our models are based on a field example in the andean foothills of argentina where gravity gliding of a 1000 m thick section is suspected above a crustal scale anticline the incision and sedimentation reduce and strengthen respectively the downslope resistance to contractional failure the critical slope at which the gliding is initiated is reduced by fluvial incision and increased by sedimentation we show that tectonic uplift may lead to large scale gravity gliding on land where the overburden thickness is less than 2000 m incision facilitates and localizes the frontal shortening incision greater than 1000 m may trigger gliding for overburden up to 4000 m thick while sedimentation thicker than 1000 m inhibits gliding these results show that thin skinned onland gravity gliding could be common in tectonically active regions where incision is important

erosion rates and sediment budgets in vineyards at 1 m resolution based on stock unearthing burgundy france abstract a new and simple method is developed to efficiently quantify erosion and deposition rates based on stock unearthing measurements this is applicable to spatial scales ranging from plot to hillslopes and to time scales ranging from single hydrologic events to centennial scales the method is applied to a plot area on vineyard hillslopes in burgundy monthelie france with measurement of 4328 vine plants a sediment budget established at the plot scale shows a mean soil lowering of 3 44 1 cm over 20 years involving a minimal erosion rate of 1 7 0 5 mm yr 1 locally erosion rates can reach up to 8 2 0 5 mm yr 1 this approach allows the sediment redistribution to be mapped and analyzed at 1 m resolution it provides novel insights into the characterization of erosion patterns on pluri decennial scales and into the analysis of spatial distribution of erosion processes on cultivated hillslopes

terrestrial sediment yield and the lifetimes of reservoirs lakes and larger basins water reservoirs lakes and larger basins including their drainage areas represent sedimentologically closed to semi closed denudation accumulation systems the mean rates of mechanical denudation drme and clastic sedimentation srme are related by the ratio of the drainage lake area ad al if the latter is known drme or the specific sediment yield sy in t per km2 a can be calculated from srme or vice versa the best data for modern sy mainly come from the sediment fills of artificial reservoirs small drainage areas of mountainous regions show sy values up to two orders of magnitude higher than lowlands and approximately one order higher than larger regions of mixed relief this is also true of arid to semi arid zones which often provide approximately as much sediment sy as humid temperate and even tropical zones of comparable relief lithology and climate river runoff also may play some role for sy from catchments of limited size the importance of these factors is exemplified by perialpine lakes and two east african lakes sediment yields gained from some large reservoirs compare well with long term denudation rates derived from geological studies e g the tarbela dam reservoir along the indus river in many other cases human activities have raised sy by factors of 2 10 locally up to 100 artificial reservoirs in mountainous regions with sy in the range of 300 2000 t per km2 a tend to become filled within several tens to hundreds of years some have even shorter lifetimes perialpine lakes of the alps and british columbia are strongly affected by delta prograding and have lifetimes mostly between 15 and 40 ka closed lake systems in deep morphological depressions lake bonneville aral sea northern caspian sea have a high potential for sediment storage up to the level of spillover and therefore can persist over long time periods basins with markedly subsiding basin floors lakes of the east african rift zone the southern caspian sea and the black sea both on oceanic crust can survive for many ma in the future despite relatively high terrigenous input

a long term estimate of bedload and suspended sediment yield derived from reservoir deposits abstract the draw down of pinmacher reservoir ayrshire west scotland in 1988 exposed sedimentary sequences entrapped since impoundment in 1903 the sole surface influent an ungauged second order stream drains a mainly undisturbed upland catchment most of the floor of the small basin is coated with mud however below the inflow a normally subaqueous delta of gravelly sand has accumulated examination of sections has enabled the construction of an isopachyte map from which the volume of deposits has been evaluated taking account of trap efficiency sediment water content and bulk densities the total sediment yield from the pinmacher catchment is 51 1 t km 2 year 1 on the assumption that the deltaic and lacustrine sequences respectively represent the bed and suspended fractions of the influent stream load long term 85 years average yields for the two components of 23 3 t km 2 year 1 and 27 8 t km 2 year 1 may be discriminated thus bedload accounts for ca 46 of the total load whilst the quantification of long term bedload transport remains elusive this study provides an unusually long record moreover analysis of the delta stratigraphy demonstrates two major and 21 additional flood events during the history of impoundment

proglacial erosion rates and processes in a glacierized catchment in the swiss alps in the swiss alps climatic changes have not only caused glacier retreat but also likely increased sedimentation downstream of glaciers this material either originates from below the glacier or from periglacial environments exposed as glaciers retreat and often consist of easily erodible sediment griesgletscher s catchment in the swiss alps was examined to quantify erosion in theproglacial area possible hydrological drivers and contributions of the sub and periglacial sources digital elevation models created from annual aerial photographs were subtracted to determine annual volume changes in the proglacial area from 1986 to 2014 these data show a strong increase in proglacial erosion in the decade prior to 2012 coincident with increasing proglacial area size however examination of the gradient between discharge and sediment evacuation and the modeled sediment transport could suggest that the proglacial area began to stabilize and sediment supply is limited the large influx of sediment into the proglacial reservoir which is roughly 2 5 times greater than the amount of sediment eroded from the proglacial area demonstrates the importance of subglacial erosion to the catchment s sediment budget although far more sediment originates subglacially erosion rates in the proglacial area are over 50 times greater than the rest of the catchment in turn both sub and periglacial processes in addition to constraining sediment supply must be considered forassessing future sediment dynamics as glacier area shrinks and proglacial areas grow

river loads and modern denudation of the alps a review this paper presents the first comprehensive analysis of sediment and dissolved load across an entire mountain range we investigate patterns and rates of modern denudation of the european alps based on a compilation of data about river loads and reservoir sedimentation from 202 drainage basins that are between ca 1 to 10 000 km2 large the study basins cover about 50 of the total area of the alps modern glaciated basins have the highest sediment yields of up to 7000 t km 2 a 1 which are on average 5 to 10 times higher than in non glaciated basins likewise sediment yield and glacial cover are positively correlated instead relief is a relatively weak predictor of sediment yield the strong glacial impact in the correlations is due to glacier recession since the 19th century as well as due to glacial conditioning during repeated quaternary glaciations which have produced the strong transient state of the alpine landscape we suggest that this is the major cause for ca 3 fold enhanced denudation of the western compared to the eastern alps chemical denudation rates are highest in the external alps dominated by carbonate sedimentary rocks where they make up about one third of total denudation the high rates cannot be explained without anhydrite dissolution we estimated that only 45 of the sediments mobilized in headwaters are exported out off the alps most sediments being trapped in artificial reservoirs the total amount of sediment annually trapped within the alps equates to 43 mt when corrected for sediment storage we obtain an area weighted mean total denudation rate for the alps of about 0 32 mm a 1 the pre dam rate might be as high as 0 42 mm a 1 in total ca 35 plus 23 mt of mass are exported each year out of the alps as solids and solutes respectively these rates are not enough to out pace modern rock uplift nevertheless pattern of sediment yield across the alps coincides roughly with the intensity of glacial conditioning and modern rock uplift supporting the hypothesis of an erosion driven uplift of the alps

the organic matter distribution and methane capacity of the lower cretaceous strata of northeastern british columbia canada abstract the methane sorption capacity of a succession of sandstone siltstone shale and coal from the lower cretaceous fort st john group of northeastern british columbia was investigated average organic matter om content for all formations is 2 3 wt with a minimum of 0 6 wt and maximum of 10 1 wt the methane sorption capacity ranges between 0 19 and 2 74 cm3 g at 6 mpa and at 30 c total gas capacity free and sorbed gas ranges between 2 2 and 16 6 cm3 g at 6 mpa micropore volumes range between 0 43 and 1 69 cm3 100 g a positive correlation exists between the om content micropore volume and the methane capacity of shales shales with high methane capacities have either high contents of inertodetrinite or vitrinite moisture content shows a positive relationship with om content micropore volume and methane capacity the negative relationship between moisture and surface area derived from n2 adsorption suggests the moisture is located within the microporosity of the om and also explains the positive relationship between methane capacity and moisture the high inertodetrinite and vitrinite contents correlate with sea level regressions that delivered terrestrial om from coastal plains located south of the study area into the basin

quantifying tectonic versus erosive denudation by the sediment budget the miocene core complexes of the alps abstract the denudation budget of the alps is quantified for the main period of lateral extrusion between 22 and 12 ma the relative importance of tectonic denudation increases from w to e from 70 in the lepontine window in the swiss alps to 80 in the tauern window and to more than 95 in the rechnitz window the driving mechanism of tectonic denudation was eastward extrusion due to an unconstrained orogenic margin in the pannonian basin tectonic denudation in the alps was responsible for about 30 of the total exhumation between 22 and 12 ma

quantifying sand provenance and erosion marsyandi river nepal himalaya we use petrographic and mineralogical data on modern sediments to investigate erosion patterns in the marsyandi basin of the central himalaya a privileged natural laboratory in which a series of multidisciplinary geomorphological sedimentological geochemical and geochronological studies have been recently carried out to unravel the interrelationships between tectonic climatic and sedimentary processes in high relief orogenic belts although relative erosion patterns are effectively constrained by analyses of replicate samples along six successive tracts of the marsyandi river uncertainties are caused by potential compositional variation between the monsoon and post monsoon season estimates of erosion rates are significantly affected by poor knowledge of total sediment flux through the basin ourresults support focusederosion of the southern tectonically lower part of the greater himalayain the hangingwall of the mct zone where thesummer monsoon reachesitspeak intensity up to 5 m a andsediment yieldsanderosion ratesreach14 100 3400t km 2 and 5 1 1 2 mm a erosion rates sharply decrease southward in low relief lesser himalayan units 1 6 0 6 mm a and also progressivelydecreasenorthwardsinthehigh altitude tectonically upperpartofthegreaterhimalaya whererainfalldecreasesrapidly to b2 m a even areas of extreme topography such as the manaslu granite are characterized by relatively low erosion rates 2 4 0 9 mm a because precipitations become too scarce to feed significant ice flux and glacial activity monsoonal rainfall decreases further tob0 5 m a in the tethys himalayan zone farther north where erosion rates are 1 mm a coupling between erosion and peak monsoonal rainfall along the southern front of the greater himalaya is consistent with both channel flow models of tectonic extrusion

palaeoenvironmental dynamics inferred from late quaternary permafrost deposits on kurungnakh island lena delta northeast siberia russia abstract late quaternary palaeoenvironments of the siberian arctic were reconstructed by combining data from several fossil bioindicators pollen plant macro fossils ostracods insects and mammal bones with sedimentological and cryolithological data from permafrost deposits the record mirrors the environmental history of beringia and covers glacial interglacial and stadial interstadial climate variations with a focus on the middle weichselian interstadial 50 32 kyr bp the late pleistocene to holocene sequence on kurungnakh island reflects the development of periglacial landscapes under changing sedimentation regimes which were meandering fluvial during the early weichselian colluvial or proluvial on gently inclined plaines during the middle and late weichselian and thermokarst affected during the holocene palaeoecological records indicate the existence of tundra steppe vegetation under cold continental climate conditions during the middle weichselian interstadial due to sedimentation gaps in the sequence between 32 and 17 kyr bp and 17 and 8 kyr bp the late weichselian stadial is incompletely represented in the studied outcrops nevertheless by several palaeoecological indications arctic tundra steppe vegetation under extremely cold arid conditions prevailed during the late pleistocene the tundra steppe disappeared completely due to lasting paludification during the holocene initially subarctic shrub tundra formed which later retreated in course of the late holocene cooling

late cenozoic increase in accumulation rates of terrestrial sediment how might climate change have affected erosion rates abstract accumulation rates of terrestrial sediment have increased in the past few million years both on and adjacent to continents although not everywhere apparently erosion has increased in elevated terrain regardless of when last tectonically active or what the present day climate in many regions sediment coarsened abruptly in late pliocene time sparser data suggest increased sedimentation rates at 15 ma approximately when oxygen isotopes in benthic foraminifera imply high latitude cooling if climate change effected accelerated erosion understanding how it did so remains the challenge some obvious candidates such as lowered sea level leading to erosion of continental shelves or increased glaciation account for increased sedimentation in some but not all areas perhaps stable climates that varied slowly allowed geomorphic processes to maintain a state of equilibrium with little erosion until 3 4 ma when large oscillations in climate with periods of 20 000 40 000 years developed and de

spatial and temporal variability of air sea co2 exchange of alongshore waters in summer near barrow alaska alongshore water off barrow alaska is a useful area for studying the carbon cycle of the arctic coastal sea because the different coastal characteristics extant in the area likely represent much larger regions of the coastal water of the western arctic ocean especially noteworthy is the inflow shelf water transferred northward by the arctic coastal current into the chukchi sea from the north pacific and turbid water in the elson lagoon where a significant amount of coastal erosion has been reported along the extensive coastal line and where a part of the water from the lagoon drains into the beaufort sea adjacent to the chukchi sea to investigate spatial and temporal variations of air sea co2 flux co2 flux of the alongshore water partial pressure of co2 of surface seawater pco2sw was measured in summer 2007 and 2008 and co2 flux was directly measured by eddy covariance at a fixed point for the beaufort sea in summer 2008 measured pco2sw in the chukchi sea side was the lowest in the beginning of the measurement season and increased later in the season both in 2007 and 2008 the average co2 flux estimated based on pco2sw in the chukchi sea side was 0 10 mmol m 2 s 1 0 1 s d using the sign convention of positive fluxes into the atmosphere from the ocean pco2sw in the beaufort sea and the elson lagoon was relatively higher in early summer and decreased in the middle of the summer the overall average co2 flux was 0 07 mmol m 2 s 1 0 1 s d for the beaufort sea side and 0 03 mmol m 2 s 1 0 07 s d for the elson lagoon respectively indicating a sink of co2 despite high carbon inflows from the terrestrial margin into the elson lagoon a strong sink of co2 was often observed from the beaufort sea by eddy covariance in the middle of the summer this sink activity in the middle summer in the beaufort sea and elson lagoon was likely due to biological carbon uptake as inferred by low apparent oxygen utilization and high chlorophyll concentration that offset a potential source of co2 due to terrestrial carbon inputs

the late quaternary sedimentary record of stave lake southwestern british columbia the postglacial sedimentary record of 59 km2 stave lake was investigated using 3 5 khz subbottom profiles and cores from the sediment surface the acoustic data show a thin cover of acoustically transparent sediment unit 1 overlying bedrock or glacial sediment on the floor of the lake overlying acoustically stratified sediment is divided into unit 2 which thins from 28 m in the south of the lake to less than 12 m in the north and unit 3 which thins from 20 m in the north to about 12 m in the south unit 1 is interpreted as resulting from deposition in a relatively quiet lacustrine or marine environment following retreat of vashon glaciers about 13 ka ago unit 2 is ascribed to deposits of sediment in runoff to stave lake from the sumas ice sheet in the fraser valley and connecting valleys to the stave basin following the retreat of the sumas ice about 11 ka ago deposition of unit 3 resulted almost entirely from sediment input from stave river entering at the north end of the lake raising the lake

response of methanogenic archaea to late pleistocene and holocene climate changes in the siberian arctic 1 in order to investigate the link between the methane dynamics in permafrost deposits and climate changes in the past we studied the abundance composition and methane production of methanogenic communities in late pleistocene and holocene sediments of the siberian arctic we detected intervals of increased methane concentrations in late pleistocene and holocene deposits along a 42 ka old permafrost sequence from kurungnakh island in the lena delta northeast siberia increased amounts of archaeal life markers intact phospholipid ethers and a high variety in genetic fingerprints detected by 16s ribosomal ribonucleic acid gene analyses of methanogenic archaea suggest presently living and presumably active methanogenic archaea in distinct layers predominantly in holocene deposits but also in deep frozen ground at 17 m depth potential methanogenic activity was confirmed by incubation experiments by comparing methane concentrations microbial incubation experiments gene analysis of methanogens and microbial life markers intact phospholipid esters and ethers to already partly degraded membrane lipids such as archaeol and isoprenoid glycerol dialkyl glycerol tetraethers we demonstrated that archaeol likely represents a signal of past methanogenic archaea the archaeol signal was used to reconstruct the response of methanogenic communities to past temperature changes in the siberian arctic and the data suggest higher methane emissions occurred during warm periods particularly during an interval in the late pleistocene and during the holocene this new data on present and past methanogenic communities in the siberian terrestrial permafrost imply that these microorganisms will respond to the predicted future temperature rise in the arctic with increasing methane production as demonstrated in previous warmer periods

deep yedoma permafrost a synthesis of depositional characteristics and carbon vulnerability abstract permafrost is a distinct feature of the terrestrial arctic and is vulnerable to climate warming permafrost degrades in different ways including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features pleistocene ice rich permafrost with syngenetic ice wedges termed yedoma deposits are widespread in siberia alaska and yukon canada and may be especially prone to rapid thaw processes freeze locked organic matter in such deposits can be re mobilized on short time scales and contribute to a carbon cycle climate feedback here we synthesize the characteristics and vulnerability of yedoma deposits by synthesizing studies on the yedoma origin and the associated organic carbon pool we suggest that yedoma deposits accumulated under periglacial weathering transport and deposition dynamics in non glaciated regions during the late pleistocene until the beginning of late glacial warming the deposits formed due to a combination of aeolian colluvial nival and alluvial deposition and simultaneous ground ice accumulation we found up to 130 gigatons organic carbon in yedoma parts of which are well preserved and available for fast decomposition after thaw based on incubation experiments up to 10 of the yedoma carbon is considered especially decomposable and may be released upon thaw the substantial amount of ground ice in yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo erosion processes mobilization of permafrost carbon is expected to increase under future climate warming our synthesis results underline the need of accounting for yedoma carbon stocks in next generation earth system models for a more complete representation of the permafrost carbon feedback

lignin depolymerization products as biomarkers of the organic matter sedimentary record in 210pb 137cs dated lake sediments abstract the composition and concentration of lignin phenols used as biomarkers of organic matter quality gradients and granulometric and mineral composition were studied in order to document land cover variations in a dated using the 210 pb method validated with 137 cs distribution sediment core from a small lake pusty staw in the coastal baltic sea area substantial gradients were found in the granulometric composition these were attributed to varying erosion caused by deforestation and afforestation of the catchment area extrapolation of the dating to deep core layers showed that the deforestation layer originated from 1730 ad close to a period of deforestation found in historical records the core dating was validated by matching a peak in the 137 cs profile with the 1986 chernobyl accident changes in the use of the catchment area caused substantial shifts in organic matter composition and quality as suggested by the gradients of syringyl s cinnamyl c and vanillic v phenols derived from cuo alkaline oxidation of lignin the lignin component of the sedimentary organic matter originated primarily from angiosperm woody material s v 0 8 c v 0 4 a new lignin parameter called delta indicating the burden of lignin derived organic matter deposited in sediments with mineral matter shows changes between the uppermost and middle zones of the core an increased ratio of vanillic acid ad to vanillone al in the uppermost sediment layers was noticed and attributed to the inflow of degraded organic matter washed out from the catchment area soil principal component and cluster analysis indicated the lignin load and quality as the main factors distinguishing the organic material in the core sections both the lignin load and quality gradients were in agreement with the lithology of the core showing the steepest gradients at the boundaries of core sections deposited prior to after the deforestation afforestation events

late quaternary sedimentation history of the lena delta abstract core and outcrop analysis from lena mouth deposits have been used to reconstruct the late quaternary sedimentation history of the lena delta sediment properties heavy mineral composition grain size characteristics organic carbon content and age determinations 14c ams and ir osl are applied to discriminate the main sedimentary units of the three major geomorphic terraces which form the delta the development of the terraces is controlled by complex interactions among the following four factors 1 channel migration according to the distribution of 14c and ir osl age determinations of lena mouth sediments the major river runoff direction shifted from the west during marine isotope stages 5 3 third terrace deposits towards the northwest during marine isotope stage 2 and transition to stage 1 second terrace to the northeast and east during the holocene first terrace deposits 2 eustasy sea level rise from last glacial lowstand to the modern sea level position reached at 6 5 ka bp resulted in back filling and flooding of the palaeovalleys 3 neotectonics the extension of the arctic mid ocean ridge into the laptev sea shelf acted as a halfgraben showing dilatation movements with different subsidence rates from the continent side differential neotectonics with uplift and transpression in the siberian coast ridges are active both likely have influenced river behavior by providing sites for preservation with uplift in particular allowing accumulation of deposits in the second terrace in the western sector the actual delta setting comprises only the eastern sector of the lena delta 4 peat formation polygenetic formation of ice rich peaty sand ice complex was most extensive 7 11 m in thickness in the southern part of the delta area between 43 and 14 ka bp third terrace deposits in recent times alluvial peat 5 6 m in thickness is accumulated on top of the deltaic sequences in the eastern sector first terrace

petrology of indus river sands a key to interpret erosion history of the western himalayan syntaxis the indus river has been progressively transformed in the last decades into a tightly regulated system of dams and channels to produce food and energy for the rapidly growing population of pakistan nevertheless indus river sands as far as the delta largely retain their distinct feldspar and amphibole rich composition which is unique with respect to all other major rivers draining the alpine himalayan belt except for the brahmaputra both the indus and brahmaputra rivers flow for half of their course along the india asia suture zone and receive major contributions from both asian active margin batholiths and upper amphibolite facies domes rapidly exhumed at the western and eastern himalayan syntaxes compositionofindussandschangesrepeatedlyandmarkedlyinladakhandbaltistan indicatingoverwhelmingsedimentflux from each successive tributary as the syntaxis is approached provenance estimates based on our integrated petrographic mineralogical data set indicate that active margin units karakorum and transhimalayan arcs provide 81 of the 250f50 10 6 t ofsedimentsreachingthetarbelareservoireachyear partitioningofsuchfluxamongtributariesandamongsourceunitsallowsus to tentatively assess sediment yields from major subcatchments extreme yields and erosion rates are calculated for both the karakorum belt up to 12 500f4700 t km 2 year and 4 5f1 7 mm year for the braldu catchment and nanga parbat massif 8100f3500t km 2 yearand3 0f1 3mm year thesevaluesapproachdenudationratescurrentlyestimatedforsouthkarakorum and nanga parbat crustal scale antiforms and highlight the major influence that rapid tectonic uplift and focused glacial and fluvial erosion of young metamorphic massifs around the western himalayan syntaxis have on sediment budgets of the indus system detailed information on bulk petrography and heavy minerals of modern indus sands not only represents an effective independent method to constrain denudation rates obtained from temperature time histories of exposed bedrock but also

use of reservoir deposits to reconstruct the recent changes in sediment yields from a small granite catchment in the yimeng mountain region china information on recent changes in sediment yields from small catchments provides a better understanding of temporal trends in soil loss from certain physical and human influenced landscapes that have been subjected to recent environmental changes and will help bridge the current knowledge gap that exists between hillslope erosion and sediment transport in rivers the yimeng mountain region characterized by alternating granite and limestone is one of the most susceptible regions to soil erosion in northern china and has been subjected to intensive anthropogenic activity in recent years soil loss from areas underlain by granite is particularly obvious and is the main sediment source for the yihe river in this study we used reservoir deposits to estimate the changes in sediment yields over the past 50 years from a small catchment underlain by granite namely the jiangzhuang catchment in the yimeng mountain region three cores were collected from the jiangzhuang reservoir in the catchment the activities of 137cs and 210pbex at different depths clay grain size 5 m contents and sedimentary organic carbon soc contents in the cores were analysed with reference to human activity and environmental change in the catchment the chronologies of the cores were established by 137cs and 210pbex dating the area specific sediment yield ssy for different time periods since dam construction was estimated from each core by referring to the original capacity curve of the reservoir the results indicate that the depth profiles of 137cs 210pbex clay and soc contents in cores from the jiangzhuang reservoir reflect the general history of human disturbances on the catchment over the past 50 years the estimated ssy value from each core for each period ranged from 7 2 2 7 to 23 7 8 3 t ha 1 y 1 with a mean of 12 5 4 6 t ha 1 y 1 ssy decreased during 1954 1972 and then showed a general tendency to increase the temporal pattern of the sediment yield largely reflects the history of environmental change influenced by human activity in the catchment

the development of permafrost bacterial communities under submarine conditions submarine permafrost is more vulnerable to thawing than permafrost on land besides increased heat transfer from the ocean water the penetration of salt lowers the freezing temperature and accelerates permafrost degradation microbial communities in thawing permafrost are expected to be stimulated by warming but how they develop under submarine conditions is completely unknown we used the unique records of two submarine permafrost cores from the laptev sea on the east siberian arctic shelf inundated about 540 and 2500 years ago to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry combined with geochemical analysis we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16s rrna gene we show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw millennia after inundation by sea water bacteria stratify into communities in permafrost marine affected permafrost and seabed sediments in contrast to pore water chemistry the development of bacterial community structure diversity and abundance in submarine permafrost appears site specific showing that both sedimentation and permafrost thaw histories strongly affect bacteria finally highest microbial abundance was observed in the ice bonded seawater unaffected but warmed permafrost of the longer inundated core suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming

lateglacial and holocene climate disturbance and permafrost peatland dynamics on the seward peninsula western alaska abstract northern peatlands have accumulated large carbon c stocks acting as a long term atmospheric c sink since the last deglaciation how these c rich ecosystems will respond to future climate change however is still poorly understood furthermore many northern peatlands exist in regions underlain by permafrost adding to the challenge of projecting c balance under changing climate and permafrost dynamics in this study we used a paleoecological approach to examine the effect of past climates and local disturbances on vegetation and c accumulation at a peatland complex on the southern seward peninsula alaska over the past 15 ka 1 ka 1000 cal yr bp we analyzed two cores about 30 m apart nl10 1 from a permafrost peat plateau and nl10 2 from an adjacent thermokarst collapse scar bog for peat organic matter om c accumulation rates macrofossil pollen and grain size analysis a wet rich fen occurred during the initial stages of peatland development at the thermokarst site nl10 2 the presence of tree pollen from picea spp and larix laricinia at 13 5 12 1 ka indicates a warm regional climate corresponding with the well documented bolling allerod warm period a cold and dry climate interval at 12 1 11 1 ka is indicated by the disappearance of tree pollen and increase in poaceae pollen and an increase in woody material likely representing a local expression of the younger dryas yd event following the yd the warm holocene thermal maximum htm is characterized by the presence of populus pollen while the presence of sphagnum spp and increased c accumulation rates suggest high peatland productivity under a warm climate toward the end of the htm and throughout the mid holocene a wet climate induced several major flooding disturbance events at 10 ka 8 1 ka 6 ka 5 4 ka and 4 7 ka as evidenced by decreases in om and increases in coarse sand abundance and aquatic fossils algae chara and water fleas daphnia the initial peatland at permafrost site nl10 1 is characterized by rapid c accumulation 66 g c m 2 yr 1 high om content and a peak in sphagnum spp at 5 8 4 6 ka suggesting the lack of permafrost a transition to extremely low c accumulation rates of 6 3 g c m 2 yr 1 after 4 5 ka at this site suggests the onset of permafrost aggradation likely in response to neoglacial climate cooling as documented across the circum arctic region a similar decrease in c accumulation rates also occurred at non permafrost site nl10 2 time weighted c accumulation rates are 21 8 g c m 2 yr 1 for core nl10 1 during the last 6 5 ka and 14 8 g c m 2 yr 1 for core nl10 2 during the last 15 ka evidence from peat core analysis and historical aerial photographs shows an abrupt increase in sphagnum spp and decrease in area of thermokarst lakes over the last century suggesting major changes in hydrology and ecosystem structure likely due to recent climate warming our results show that the thermokarst permafrost complex was much more dynamic with high c accumulation rates under warmer climates in the past while permafrost was stabilized and c accumulation slowed down following the neoglacial cooling in the late holocene furthermore permafrost presence at local scales is controlled by both regional climate and site specific factors highlighting the challenge in projecting responses of permafrost peatlands and their c dynamics to future climate change

petroleum geology of the black sea abstract the black sea comprises two extensional basins formed in a back arc setting above the northward subducting tethys ocean close to the southern margin of eurasia the two basins coalesced late in their post rift phases in the pliocene forming the present single depocentre the western black sea was initiated in the aptian when a part of the moesian platform now the western pontides of turkey began to rift and move away to the south east the eastern black sea probably formed by separation of the mid black sea high from the shatsky ridge during the palaeocene to eocene subsequent to rifting the basins were the sites of mainly deep water deposition only during the late miocene was there a major sea level fall leading to the development of a relatively shallow lake most of the margins of the black sea have been extensively modified by late eocene to recent compression associated with closure of the tethys ocean gas chromatography mass spectrometry and carbon isotope analysis of petroleum and rock extracts suggest that most petroleum occurrences around the black sea can be explained by generation from an oil prone source rock of most probably late eocene age although a wider age range is possible in the basin centres burial history modelling and source kitchen mapping indicate that this unit is currently generating both oil and gas in the post rift basin a palaeozoic source rock may have generated gas condensate in the gulf of odessa in bulgarian waters the main plays are associated with the development of an eocene foreland basin kamchia trough and in extensional structures related to western black sea rifting the latter continue into the romanian shelf where there is also potential in rollover anticlines due to gravity sliding of neogene sediments in the gulf of odessa gas condensate has been discovered in several compressional anticlines and there is potential in older extensional structures small gas and oil discoveries around the sea of azov point to further potential offshore around the central azov high in offshore russia and georgia there are large culminations on the shatsky ridge but these are mainly in deep water and may have poor reservoirs there are small compressional structures off the northern turkish coast related to the pontide deformation these may include eocene turbidite reservoirs the extensional fault blocks of the andrusov ridge mid black sea high are seen as having the best potential for large hydrocarbon volumes but in 2200 m of water

towards a reconstruction of blue nile baseflow from ethiopian tree rings most of the water in the river nile originates from monsoonal rainfall over the ethiopian highlands despite warnings of future climate change little is known about the historical variability in this supply particularly at annual resolution development of tree ring records in this region has been limited by the occurrence of bi or multimodal rainfall regimes causing the development of multiple growth rings that cannot be dated with confidence in this study we identified annual rings in 30 juniperus procera trees from northwest ethiopia by dendrochronology and ams radiocarbon dating carbon isotope ratios 4 series and ring widths 73 series were measured the carbon isotope series did not contain strong trends possibly attributable to increased anthropogenic atmospheric co2 concentrations or the juvenile effect both carbon isotope values and ring widths were strongly correlated with blue nile baseflow and from composite chronology indices r 0 75 p 0 01 a preliminary reconstruction of blue nile baseflow back to ad 1836 was developed subsample signal strength remained above 0 85 for most of the reconstruction uncertainty bands were relatively narrow and the reliability of the preliminary reconstruction was confirmed by correspondence with reported years of drought and famine the preliminary reconstruction is characterized by an exceptional decline in baseflow during the late ad 1960s flows recovered during the late 1990s additional sampling is advised to increase replication spatial coverage and length of the preliminary reconstruction

reconstructing discharge of beas river basin kullu valley western himalaya based on tree ring data abstract tree ring data of cedrus deodara deodar growing within the beas river basin kullu valley himachal pradesh in western himalaya have been analyzed in relation to streamflow reconstruction the correlation between deodar tree ring chronology and river discharge data from various gauge stations of the beas river basin showed positive relationships with early summer months march april streamflow of these months has been reconstructed using a simple linear regression transfer function model which goes back to ad 1834 explained variances during the calibration period are 43 7 and 60 6 for two gauge stations bhuntar and thalout respectively in the reconstructed data ad 1834 1984 the periods of highest streamflow were during ad 1840 1843 1893 1897 1922 1926 1935 1940 and 1942 45 and lowest were during the years ad 1847 1851 1863 66 1927 1929 1960 1962 and 1972 1974 spatial coherence analysis between the reconstructed series with regional gridded precipitation and nearby longest instrumental precipitation records showed coincidence with drought and wet periods through the spatial correlation analysis between reconstructed march april runoff and gridded palmer drought severity index pdsi a common regional moisture variation was identified