soil formation in coastal continental antarctica wilkes land recent antarctic soil studies suggest that in terrestrial ecosystems of coastal regions soil formation and chemical weathering occur to a greater extent than predicted by former models this paper summarizes pedogenic findings from the casey area on the coast of east antarctica and presents a proposal of soil formation sequences on a large scale data base soil organic matter accumulation and podzolization are important soil forming processes in regions outside the antarctic cold desert of the ross sea section the results suggest some correlations between the soil development and vegetation patterns nutrient supply in soil is affected by the high contents and availability of nitrogen phosphorus potassium and magnesium due to an input by seabirds the us soil taxonomy 8th edn gelisol order and the recently adopted world reference base for soil resources wrb cryosol soil group suggest a different understanding of impact of permafrost on soil formation according to the wrb and the us soil taxonomy organic permafrost affected soils are not cryosols but gelisols lithic haplorthels as well as haploturbels and to some extent aquaturbels and organic gelisols are suggested to be representative of the casey area in addition podzols occur to a great extent however the recent keys to soil taxonomy do not reflect the podzolization process in an adequate way and a classification is not possible according to a former version these soils would be lithic or pergelic haplocryods whereas according to the newly adopted wrb system these soils are spodic haplic cryosols

distribution of soil taxa in antarctica a preliminary analysis abstract only 0 35 49 500 km2 of antarctica is ice free these areas are scattered around the periphery of the continent and in interior mountain ranges making soil mapping difficult here we compile the results of mapping in five of the nine ice free areas that account for 79 of the ice free area on a reconnaissance scale and interpret the distribution of soil subgroups in soil taxonomy soils of antarctica are contained in four orders dominantly gelisols 84 13 suborders 27 great groups and 76 subgroups forty five percent of the soils of antarctica are orthels gelisols that show minimal cryoturbation and occur in dry landscape positions 38 of the soils are turbels showing cryoturbation and occurring in more moist landscape positions only 16 of the soils of antarctica lack permafrost in the control section and are classified as entisols gel great groups inceptisols gelepts suborder or gelaquepts or histosols gel great groups these soils occur almost exclusively along the western antarctic peninsula and at elevations below 30 m in the south shetland islands ssi and south orkney islands soi typic anhyorthels are the dominant soil subgroup comprising nearly 15 340 km2 or 31 of the soils in antarctica these soils occur primarily in central and southern victoria land but also occur in the thiel and pensacola mountains and shackleton range the prince charles mountains and the mountains of queen maud land typic haploturbels and typic anhyturbels occupy 14 and 13 of the soils of ice free regions of antarctica respectively most abundant in central victoria land they are common in most mountainous regions of antarctica the dominant soil processes of maritime antarctica are cryoturbation gleization melanization podzolization paludization and phosphatization in coastal east antarctica the major soil processes are rubification salinization calcification pervection and gleization the predominant soil forming processes in the transantarctic mountains include rubification salinization desert pavement formation and permafrost development measures of pedodiversity will be valuable in the selection of protected areas in antarctica

sediment sources and siltation in mountain reservoirs a case study from the central spanish pyrenees abstract based on a 137 cs derived chronology we reconstruct the depositional history of the barasona reservoir in the esera isabena basin central pyrenees spain most of the sediments were delivered to the barasona reservoir during flood events comparative mineralogical studies of the esera and isabena river channels and the barasona reservoir sediments help to identify sediment sources and areas of high sediment yield risk and to establish erosion and sediment transport processes in the watershed changes in the mineralogical composition of the sediments can be used to discriminate the relative contribution of the esera and isabena rivers during flood periods three main periods in the siltation history of the barasona reservoir were distinguished 1 from dam construction 1932 to the early 1950s the reservoir was flushed every year using the lower gates and average sediment accumulation was very low 1 5 cm yr 2 during the 1950s and 1960s the sedimentation rate increased and reached the highest values 15 cm yr 24 6 cm yr and 18 2 cm yr in the esera river mouth the northern and the southern areas of the reservoir respectively both changes in the exploitation regime no annual flushes and climate variability increased flood frequency and river inflow caused this increase in sediment delivery and accumulation 3 the third period was initiated by the enlargement of the dam in 1972 the new sedimentary dynamics in the reservoir caused a general decrease in the sedimentation rate 11 6 cm yr in the southern areas 10 cm yr in the esera mouth that was especially noticeable in the northern areas where the accumulation rate was reduced to 3 7 cm yr an increase in channel erosion processes during this period contributed to the transport of sediments to the inner areas of the reservoir

137cs and 210pb derived sediment accumulation rates and their role in the long term development of the mkuze river floodplain south africa abstract wetlands are well known to act as sinks for sediment and chemicals in the landscape within the mkuze river floodplain in northern kwazulu natal south africa deposition of clastic sediment occurs predominantly in close proximity to the river channel resulting in the formation of levees over time this leads to channel avulsion a process that may be accelerated by the activities of hippopotami whose trails create hydraulically favourable pathways sedimentation rates determined using the isotopes 210pb and 137cs indicate that the mkuze river floodplain is a relatively rapidly aggrading system that should experience frequent avulsion with average short term rates in the order of 0 25 to 0 50 cm y sediments on the floodplain are also an important sink for solutes which concentrate in the groundwater and precipitate out because of evapotranspiration over long timescales chemical sedimentation affects the landscape by influencing salinity vegetation distribution hydrological flows and local topography the mkuze river floodplain is an actively evolving system which continues to aggrade as a result of the combination of clastic and chemical sedimentation in a region characterised by a strong annual water deficit temporal patterns of clastic and chemical sedimentation are likely to exert influence on the long term development of wetland systems elsewhere in southern africa this study the first on sediment accretion rates using 210pb and 137cs dating for a southern african wetland demonstrates that radioisotopic methods are an important tool that can be applied toward fully understanding wetland formation evolution and functioning in the region

chemistry and microstructures of clay particles in smectite rich shelf sediments south shetland islands antarctica the clay mineralogy of a holocene sediment core from the shelf of livingston island south shetland islands antarctica has been investigated by x ray diffraction xrd lattice imaging bulk chemical analysis of fine clay fractions and analytical transmission electron microscopy atem the clay minerals identified by xrd of 2 m fraction are smectite 63 chlorite 25 and illite 12 with little downcore variation lattice imaging of clay particles has confirmed the presence of interstratified illite smectite and interstratified chlorite smectite atem of ca saturated samples showed that the smectitic clay particles are rich in k fe and mg k in the smectitic particles is mostly present as a fixed cation in the interlayer confirming the presence of interstratified illite a comparison of the mineralogy of the bedrock soils in the probable source area and the core sediment strongly supports the view that the clay minerals must have originated by glacial erosion physical weathering and reworking of hydrothermally altered volcanic bedrock and tephra of the south shetland islands

factors controlling sediment yield from small intensively cultivated catchments in a temperate humid climate abstract data on sediment yield from 26 small cultivated catchments 10 10 000 ha in central belgium were collected based on sedimentation rates in small flood retention ponds area specific sediment yield varies from 0 4 to 20 6 t ha 1 year 1 for catchments ranging from 7 to 4873 ha various catchment properties were analysed in order to understand this large variation in sediment yield catchment area alone explains 64 of the observed variance in area specific sediment yield although no other parameter could explain more it is concluded that catchment area is not a valid parameter to link with sediment yield overall catchment geomorphology e g presented by the hypsometric integral is much more important in controlling sediment yield the lack of data however made this not very clear a multiple regression model including three morphological catchment properties is a valuable tool to predict total sediment yield t year 1 from catchments in central belgium this model has an efficiency of 0 81 furthermore it was concluded that the within catchment spatial distribution of parameters for instance slope steepness is very important but difficult to obtain one single representative value the use of spatially distributed erosion and sediment delivery models is therefore necessary accurate sediment yield data like the one presented in this study however are needed to validate these models

stratigraphy and regional significance of the upper jurassic lower cretaceous byers group livingston island antarctica the byers group exposed on byers peninsula western livingston island antarctica comprises a mudstone dominated sequence at least 1 km thick which accumulated in a marginal fore arc environment the basal 105 m thick anchorage formation consists of radiolarian mudstones and tuff rich interbeds of kimmeridgian tithonian age it correlates with upper jurassic organic rich mudstone units throughout the proto south atlantic region the succeeding 244 m thick devils point formation marks the first major pulse of coarse volcaniclastic material into the basin it is in turn followed by the extensive president beaches formation comprising several hundred metres of finely laminated mudstones with at least two major sandstone intercalations molluscan and dinoflagellate cyst taxa indicate a berriasian age and comparatively nearshore depositional environment for this unit an unconformity of late berriasian or early valanginian age separates the three lowest formations from the chester cone formation the fine grained sealer hill member at the base of the latter is dated as valanginian and grades up into several hundred metres of pebbly sandstones and pebble granule conglomerates these mark the second major volcaniclastic pulse and may be of hauterivian or even younger age definition of this major new group will facilitate more precise upper jurassic lower cretaceous stratigraphical correlations within the southern south america scotia arc antarctic peninsula region it will also aid our understanding of the critical palaeogeographical transition in the northern antarctic peninsula from anoxic basin to active magmatic arc

estimates of late holocene soil production and erosion in the snowy mountains australia soil production in actively uplifting or high precipitation alpine landscapes is potentially rapid however these same landscapes are also susceptible to erosion and can be sensitive to changes in climate and anthropogenic activity which can upset the balance between soil production and erosion the snowy mountains southeastern australia are a tectonically stable low relief moderate precipitation mountain environment the alpine area is extensively blanketed by soil that has been subjected to more intensive episodes of erosion during past periods of anthropogenic disturbance and under cold climate conditions of the late quaternary in this study rates of soil development and hillslope erosion were investigated using radiocarbon dating fallout radionuclides and sediment cores collected from lakes and reservoirs estimated holocene soil development rates were 20 220 t km y erosion rates determined from the radionuclides cs and pb were equivocal due to the inherent spatial variability of radionuclide inventories relative to apparent erosion rates estimated average erosion rates over the past 100 years determined from pb inventories were 60 t km y 95 ci 10 90 inventories of cs observed at the same site implied that more recent erosion rates over the past 60 years was below the detection limits of the sampling method applied here i e 70 t km y the upper estimate of 90 t km y is comparable to the mean erosion rate estimated using the radionuclide method for uncultivated sites in australia and is significantly lower than that measured at sites were vegetation cover was disturbed by livestock grazing prior to its exclusion from the alpine area in the 1940s ce low erosion and high soil production rates relative to the lowland soils are likely related to extensive vegetation cover which in this context protects soils against erosion and contributes to the formation of organic alpine soils that rapidly accumulate organic matter by comparison to other soil types

210pb geochronology of sediment accumulation rates in mexico city metropolitan zone as recorded at espejo de los lirios lake sediments abstract a sedimentary sequence from the espejo de los lirios lake in the metropolitan zone of mexico city mzmc was analyzed in detail for 210 pb and 137 cs activities allowing to assess the evolution of the accretion rates in the lake during the last 84 4 years the core revealed the deposition of contemporaneously indigenous lake sediments to the site interspersed with eroded bedrock from the catchment evidencing episodic increases in sediment accretion which varied from 0 14 to 0 93 cm year 1 increasing trends in sedimentation rates were found to be closely related to demographic expansion of the metropolitan zone of mexico city and explained on the basis of the erosive processes produced as a result of deforestation created as a consequence of the urban and industrial development of the mzmc

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

sediment yield estimation in a small watershed on the northern loess plateau china abstract soil erosion is a major form of land degradation throughout the world and the key environmental problem that threatens the ecosystem of the chinese loess plateau in this study we determined the sediment yield from a small dam controlled watershed in the huangfuchuan watershed northern loess plateau with a drainage area of 0 64 km2 the dam infill sediment provided evidence of at least 31 flood couplets which corresponded to rain storms during 1958 1972 in total 1 65 105 t sediment was accumulated within the whole check dams in this period the annual sediment yield ranged from null in 1965 to 59 990 t in 1959 we used the modified watem sedem model to simulate soil erosion and the sediment yield in the watershed and the sedimentation records were used for model verification the model produced satisfactory results the total soil erosion and sediment delivery ratio were estimated to be 1 97 105 t and 83 6 respectively bare weathered stone in the steep gullies contributed 90 of the sediment yield while the remainder was derived mainly from bare loess slopes and the alluvial plain this study suggests that analyzing sedimentation behind check dams and applying the watem sedem model are useful for the quantitative analysis of sediment dynamics in ungauged basins on the loess plateau

accumulation and properties of soil organic carbon at reclaimed sites in the lusatian lignite mining district afforested with pinus sp abstract the accumulation of organic carbon mainly derived from litter fall and necromass corg recent has been investigated within the forest floor horizons and the mineral topsoil 0 4 cm and 4 10 cm at reclaimed forest stands of the lusatian lignite mining district as well as on an undisturbed forest stand in the general region planted with pinus sylvestris l or pinus nigra arnold recently formed organic carbon corg recent was differentiated from organic carbon derived from lignite and lignite derivatives corg geogenic which are inherent in the dumped substrate at post mining sites by 14 c measurements total organic carbon toc was characterized by 13 c cpmas nmr spectroscopy the storage of toc corg recent corg geogenic and of organic carbon structures was examined we found that the accumulation of corg recent increased with stand age at all investigated stands the results indicate that at the reclaimed stands accumulation of corg recent takes place in the same order of magnitude when compared to the undisturbed stand storage of toc in the mineral topsoil 0 10 cm amounted from 2 6 kg m 2 to 7 0 kg m 2 at the reclaimed stands and to 2 6 kg m 2 at the undisturbed stand at reclaimed stands toc in the mineral topsoil can be attributed mainly to corg geogenic the calculated pools of corg geogenic effect physico chemical soil properties our results indicate that corg geogenic in the substrate may compensate in part the lack of soil organic matter derived from soil development as storage for nutrients and water

the origin of clay minerals in soils of king george island south shetland islands west antarctica and its implications for the clay mineral compositions of marine sediments abstract clay minerals in the soils of king george island south shetland islands west antarctica were investigated to evaluate their influence upon the composition of marine sediments derived from them paleohydrothermal activity has developed phyllic argillic alteration zones in restricted areas of the volcanic bedrock illite and kaolinite show a highly localized distribution in the soils of the phyllic argillic zones whereas chlorite dominates in the soils of unaltered bedrock the localized distribution indicates that illite and kaolinite are residues from altered bedrock whereas chlorite originates from unaltered bedrock smectite in the soils is rather uniformly distributed with no relationship to the phyllic argillic zones it is mostly the alteration product of eolian pumice shards which are found scattered throughout the soils on a microscopic scale the eolian provenance of smectite associated with pumice shards is supported by a uniform distribution of smectite coexistence of fresh and altered pumice shards and rather short exposure after deglaciation smectites likely have been formed in a remote source around volcanic craters and reworked by repeated eruptions formation of clay minerals by chemical weathering as suggested in previous studies appears to be insignificant on king george island even though the climate is warmer and more humid than in other antarctic regions smectite and kaolinite in seafloor sediments around the south shetland islands do not indicate chemical weathering in the source area instead their occurrence suggests that volcanism igneous intrusion and related hydrothermal alterations were active in the south shetland islands during the cenozoic

semi arid soils from a topolithosequence at james ross island weddell sea region antarctica chemistry mineralogy genesis and classification abstract climate and parent material have a significant impact on the development of antarctic soils and areas dominated by basaltic andesitic volcanic rocks sedimentary rocks and metamorphic rocks have been widely studied james ross island located in the semi arid transition between east antarctic peninsula weddell sea sector receives both continental and maritime climatic influences resulting in distinct transitional soil formation process in antarctica there is little research on semi arid soils formed on volcano sedimentary rocks as well as their pedogenetic processes in this study a topolithosequence of volcanic and sedimentary rocks in this semi arid transitional climate was investigated nine profiles three on marine terraces four on sedimentary rocks and two on volcanic rocks were described sampled and analyzed for morphological physical chemical and mineralogical properties soils are predominantly gelisols cryosols and present cryoturbation features despite the current dry climate vegetation is scarce and nesting birds are absent so that most soils can be characterized as ahumic all profiles have a skeletic character with a high percentage of coarse materials the soil ph varied from neutral to alkaline and the potential acidity values were null the mineralogy of the clay fraction presented kaolinite which was likely inherited from warmer and wetter paleoclimatic conditions during sedimentation the soils have intergrade properties between maritime and continental antarctic such as cryoturbation and redoximorphism side by side with desert pavements and ahumic character soil properties were more sensitive to the variations in parent material than to the topographic position in the landscape

geomorphological mapping of ice free areas using polarimetric radarsat 2 data on fildes peninsula and ardley island antarctica satellite borne synthetic aperture radar sar has been used for characterizing and mapping in two relevant ice free areas in the south shetland islands the objective has been to identify and characterize land surface covers that mainly include periglacial and glacial landforms using fully polarimetric sar c band radarsat 2 data on fildes peninsula that forms part of king george island and ardley island polarimetric parameters obtained from the sar data a selection of field based training and validation sites and a supervised classification approach using the support vector machine were chosen to determine the spatial distribution of the different landforms eight periglacial and glacial landforms were characterized according to their scattering mechanisms using a set of 48 polarimetric parameters the mapping of the most representative surface covers included colluvial deposits stone fields and pavements patterned ground glacial till and rock outcrops lakes and glacier ice the overall accuracy of the results was estimated at 81 a significant value when mapping areas that are within isolated regions where access is limited periglacial surface covers such as stone fields and pavements occupy 25 and patterned ground over 20 of the ice free areas these are results that form the basis for an extensive monitoring of the ice free areas throughout the northern antarctic peninsula region

fallout 210pb as a soil and sediment tracer in catchment sediment budget investigations a review increasing anthropogenic pressures coupled with climate change impacts on natural resources have promoted a quest for innovative tracing techniques for understanding soil redistribution processes and assessing the environmental status of soil resources among the different existing tracers the fallout component of the radioisotope lead 210 also termed unsupported or excess lead 210 pb 210 ex when referring to its presence in soil or sediment arguably offers the broadest potential for environmental applications due to its origin and relatively long half life for more than five decades pb 210 ex has been widely used for dating sediments to investigate sedimentation processes and since the 1990s to provide information on the magnitude of soil and sediment redistribution the aim of this review is to provide a comprehensive evaluation and discussion of the various applications of pb 210 ex as a tracer in terrestrial and aquatic environments with particular emphasis on catchment sediment budget investigations this paper summarizes the state of the art related to the use of this tracer the main assumptions the requirements including the need for accurate analytical measurements and for parallel validation and the limitations which must be recognised when using this fallout radionuclide as a soil and sediment tracer lessons learned and current and future research needs in the environmental and radiochronological application of pb 210 ex are also presented and discussed c 2014 elsevier b v all rights reserved

distribution and characterization of soils and landform relationships in byers peninsula livingston island maritime antarctica abstract this paper presents the spatial distribution of soils from the northern part of byers peninsula livingston island which is the largest ice free area of the south shetlands archipelago maritime antarctica physical and chemical characteristics are presented for 23 soil profiles soil parent materials vary from marine sedimentary to volcanic and volcanoclastic rocks intruded by igneous bodies to assess soil landscape relationships twenty three soil profiles were described and sampled soil samples of selected horizons were submitted to chemical physical and mineralogical analyses soil mapping was based on the soil profiles integrated with the existent topographic map 1 25 000 scale a digital elevation model the geological map and a satellite image twenty different soil units were identified and mapped according to the world reference base for soil resources wrb system soils were classified as fluvisols regosols leptosols or cryosols which correspond mostly to fluvents orthents psamments inceptsols and gelisols respectively according to the soil taxonomy soils from northern byers peninsula are generally shallow and coarse textured with low organic matter content three soils from the rocky platforms of the northern coastal region possess ornithogenic character with lower ph higher p al 3 and organic c values when compared to soils not influenced by sea birds in non ornithogenic soils the presence of easily weatherable minerals in the clay fraction indicates that physical weathering occurs with limited chemical alteration of primary minerals the influence of penguin and other birds on coastal soils alters clay mineralogy with formation of poorly crystalline p rich phases a better understanding of the depth of the permafrost table and the spatial distribution of permafrost is necessary for a more conclusive classification of cryosols or gelisols

dating reservoir deposits to reconstruct sediment yields from a small limestone catchment in the yimeng mountain region china abstract in this study we use reservoir deposits to reconstruct sediment yields over the past 50 years from the quananzi catchment a small limestone catchment in the yimeng mountain region china three sediment cores were collected from the reservoir and the chronology of each core was established using 137cs and 210pbex dating the area specific sediment yields ssy for different time periods since dam construction were estimated from each core by referring to the original capacity curves of the reservoir the estimated ssy from the quananzi catchment in each core for each period ranged between 0 9 0 3 and 2 6 0 9 t ha 1 y 1 with a mean value of 1 8 0 6 t ha 1 y 1 which is low compared with reported ssy from catchments worldwide the mean value was only about 1 7 of the equivalent value reported from the jiangzhang catchment in the granite area of the yimeng mountain region this low ssy reflects the shortage of erodible luvisols resistance to erosion and the limited effect of human disturbance in this small limestone catchment the decrease in ssy from 1959 to1972 suggests that the effect of the deforestation that occurred in 1958 on soil erosion decreased with time the continual increase of ssy through the two subsequent periods after 1972 reflects the expansion and intensification of cultivation during this time however the decreased ssy over the latest period of 1998 2012 can be related to the limitations imposed by the karst landscape on cultivation and to the impact of increasing numbers of residents leaving the area since the end of the 1990s to become temporary migrant workers elsewhere resulting in a decrease in human activity in the area overall the trend in ssy reflects the general history of changing human disturbance in this small limestone catchment over the past 50 years the results indicate that reservoir deposits provide a means of estimating the historical sediment yields from a karstic environment

origin of crystalline cold desert salts in the mcmurdo region antarctica abstract the distribution of crystalline salt minerals in deposits in the mcmurdo region of antarctica has been examined to study the origin of these salts sulphate chloride sodium and calcium salts are most frequently encountered salts containing chloride and sodium ions become less common away from the coast sulphate salts are more regularly distributed but tend to be related isotopically to sea water sulphate salts containing magnesium ion tend to exist mainly on substrates composed of basic igneous rocks whereas calcium and carbonate salts are present on all rock types in the region these distributions show that salts of marine origin are regionally and quantitatively most important but that chemical weathering of mafic materials in rocks and soils is also significant however biological volcanic and hydrothermal processes are or have been active contributing to salts in local areas that include penguin rookeries and eastern taylor valley the summit area of erebus volcano and subsurface rocks respectively

radionuclide dating of recent sediment and the validation of pollen environment reconstruction in a small watershed reservoir in southeastern china abstract a 76 cm sediment core was collected from the huangdong reservoir southeastern china the radionuclides 137 cs and 210 pb and sediment grain size analysis were applied to establish the chronology and modern sedimentation rates the chronology established by the 137 cs time markers was consistent with the constant flux constant sedimentation cfcs model and the known time of dam construction 1960 ad recognized from the curve of sediment grain size at the depth of 54 cm the results show that the sedimentation rate of the huangdong reservoir is relatively high implying that soil erosion and water loss were strong the sedimentation rate before the construction of the reservoir was approximately 1 5 cm a which belongs to the fluvial flooding deposit the rate decreased to approximately 1 0 cm a during the reservoir deposition since 1960s pollen and micro charcoal analysis were performed to test the reliability of pollen based environment reconstruction including vegetation cover deforestation planting and fire disasters the results of pollen and micro charcoal indicated that the herbs primarily gramineae ferns such as dicranopteris and several trees mainly pinus varied following chorography or historical records we discovered that the most important indicators for local forest cover changes are pollen concentration and the ap nap value ratio of arboreal pollen to non arboreal pollen human impact on forests is manifested by a sharp decrease in pollen percentage of trees and absolute pollen concentration forest fire events were recorded by the peaks of charcoal concentration and the c p value ratio of charcoal concentration to pollen concentration for example the massive deforestation and intensive fires during the great leap forward movement and the cultural revolution are reflected by pollen and micro charcoal spectra this work testifies that radionuclide use as a dating method is applicable in southern china and the 137 cs method has demonstrated its reliability in the small reservoir setting in spite of low absolute values the environmental proxies such as grain size pollen and charcoal are sufficiently sensitive to reveal local ecosystem changes caused by natural disasters or human activity

active layer dynamics in three topographically distinct lake catchments in byers peninsula livingston island antarctica abstract topography exerts a key role in controlling permafrost distribution in areas where mean annual temperatures are slightly negative one such case is the low altitude environments of maritime antarctica where permafrost is sporadic to discontinuous below 20 40 m asl and continuous at higher areas and active layer dynamics are thus strongly conditioned by geomorphological setting in january 2014 we installed three sites for monitoring active layer temperatures across byers peninsula livingston island south shetland islands at elevations between 45 and 100 m the sites are situated in lake catchments lakes escondido cerro negro and domo that have different geomorphological and topographical conditions our objective was to examine the role of topography and microclimatic conditions in determining the active layer thermal regime in order to identify the factors that control geomorphic processes in these lake catchments at each site a set of loggers was installed to monitor air temperature at snow thickness swt and soil temperature st down to 80 cm depth mean annual air temperatures maat showed similar values in the three sites 2 7 to 2 6 c whereas soil temperatures showed varying active layer thicknesses at the three catchments the ground thermal regime was strongly controlled by soil properties and snow cover thickness and duration which is influenced by local topography geomorphological processes operating at the lake catchment scale control lacustrine sedimentation processes and both are dependent on the combination of topographical and climatic conditions therefore the interpretation of lake sediment records from these three lakes requires that soil thermal regime and snow conditions at each site be taken into account in order to properly isolate the geomorphological environmental and climatic signals preserved in these lake records

soil characteristics on varying lithological substrates in the south shetland islands maritime antarctica abstract soils in ice free areas of livingston island have been forming since the last deglaciation in a maritime warmer climate that is more humid than in interior antarctica a soil survey was carried out on byers and hurd peninsulas to characterize the soils and investigate the processes soils were sampled on two different substrates mudstones and volcanic rocks in byers peninsula and greywackes in hurd peninsula sampling sites were located on raised beaches platforms and on volcanic outcrops across an altitudinal range from few m to 150 m a s l the ph electrical conductivity carbonates and organic matter showed similar patterns in each geomorphic unit but their values differed between bedrocks the sand silt and clay contents differed greatly in the soils on mudstones and volcanic rocks the elemental composition was closely related to mineralogy of parent materials mg k zn mn and fe were similar in the soils on all bedrocks the al content was highest on the volcanic rocks the largest difference in the ca content was between the soils on greywackes and mudstones the na pb and ba contents in soils on the mudstones differed greatly from the rest of bedrocks geochemical and mineralogical characteristics suggest that the main process involved in soil development was the mechanical disintegration of bedrock although there was also some leaching cryogenic processes play a key role in soil development but chemical weathering processes were also involved in soil evolution although limited in extent due to the restriction of water circulation to summer

effects of land use land cover and rainfall regimes on the surface runoff and soil loss on karst slopes in southwest china abstract surface runoff and soil loss from 2007 to 2010 related to land use and rainfall regimes in karst hill slopes in guizhou province southwest china were analyzed using the hierarchical clustering method sixty one rainfall events under the subtropical monsoon climate condition were classified into 5 types of rainfall regimes according to the depth maximum 30 min intensity and duration of rainfall in our study we first demonstrated that the amounts of surface runoff and soil loss on the karst hill slopes were very small compared to the non karst areas because the dual hydrological structure in the karst region including ground and underground drainage systems could influence the processes of rainfall recharge and runoff generation most rainfall water was transported underground through limestone fissures and fractures while little was in the form of surface runoff second the runoff and soil loss were affected by land use management and vegetation cover soil loss was intensified in a descending order to five types of land uses pastureland burned area cropland combination vegetation land young forestland third the runoff and soil loss exhibited remarkable variances among different rainfall regimes large runoff and soil loss were mainly created by heavy rainfall storms with a rainfall depth of more than 40 mm and a maximum 30 min rainfall intensity of over 30 mm h 1 in addition rainfall storms with large antecedent precipitations could also produce large runoff and soil loss these observations indicated that limestone fissures and fractures play important roles in surface runoff generation on karst limestone slopes due to their large storage capacity and high infiltration rate lastly the soil erosion risk in the karst pure limestone slope is quite high and should be paid particular attention especially in regards to over grazing because the soil loss created by a single heavy rainstorm in pastureland was 5 times the annual soil loss tolerance

the history of human induced soil erosion geomorphic legacies early descriptions and research and the development of soil conservation a global synopsis abstract this paper presents a global synopsis about the geomorphic evidence of soil erosion in humid and semihumid areas since the beginning of agriculture historical documents starting from ancient records to data from the mid twentieth century and numerous literature reviews form an extensive assortment of examples that show how soil erosion has been perceived previously by scholars land surveyors farmers land owners researchers and policy makers examples have been selected from ancient greek and roman times and from central europe southern africa north america the chinese loess plateau australia new zealand and easter island furthermore a comprehensive collection on the development of soil erosion research and soil conservation has been provided with a particular focus on germany and the usa geomorphic evidence shows that most of the agriculturally used slopes in the old and new worlds had already been affected by soil erosion in earlier prehistoric times early descriptions of soil erosion are often very vague with regard to the roman times geomorphic evidence shows seemingly opposing results ranging from massive devastation to landscapes remaining stable for centuries unfortunately historical documentation is lacking in the following centuries historical records become more frequent and more precise and observations on extreme soil erosion events are prominent sometimes they can be clearly linked to geomorphic evidence in the field the advent of professional soil conservation took place in the late eighteenth century the first extensive essay on soil conservation known to the western world was published in germany in 1815 the rise of professional soil conservation occurred in the late nineteenth and early twentieth centuries soil remediation and flood prevention programs were initiated but the long term success of these actions remains controversial in recent years increasing interest is to recover any traditional knowledge of soil management in order to incorporate it into modern soil conservation strategies the study shows that local and regional variations in natural settings cultural traditions and socioeconomic conditions played a major role for the dynamics and the rates of soil erosion on a long term perspective geomorphic evidence and historical sources can often complement each other but there should be also an awareness of new pitfalls when using them together

runoff and erosion processes on bare slopes in the karst rocky desertification area underground pore fissure and bedrock bareness are the main factors that lead to complicated mechanisms of soil erosion in karst regions the objectives of this study were as follows a to measure runoff and sediment generated from the surface and underground in the karst bare slope and b to analyse the impacts of underground pore fissures and bedrock bareness rates on soil erosion to achieve these objectives we designed an experiment in which underground pore fissure degrees and bedrock bareness rates were varied and their impacts on soil erosion were measured the results showed that runoff and sediment yields from the surface and underground increased with increasing rainfall intensity and the surface runoff was much more easily generated when the rainfall intensity was greater ii surface runoff yield first increased and then decreased with increasing bedrock bareness rates while the runoff yield in underground pore fissures increased with increasing bedrock bareness rates thus sediment production on the surface and in underground pore fissures showed the same pattern i e first decreased and then increased iii the surface runoff and sediment generally decreased with increasing degrees of underground pore fissures while that of underground pore fissures presented a different pattern and iv rainfall intensity bedrock bareness rates and underground pore fissure degrees were the important factors affecting soil erosion processes in karst bare slopes because the bedrock bareness rates and underground pore fissure degrees were the main factors causing the uneven distribution of runoff and sediment on soil surfaces and underground therefore soil and water loss in underground pore fissures was the special pattern and main difference in soil erosion processes in the karst region compared with other regions these results have theoretical and practical significance for understanding soil erosion mechanisms and controlling soil and water loss in karst regions

a review of pedogenic zonation in well drained soils of the southern circumpolar region abstract the concept of zonality is used to link well drained mineral soils and processes along a bioclimatic gradient extending from ca 48 to 87 s including southernmost chile the subantarctic islands and maritime and continental antarctica the following environmental factors decline along this gradient mean annual temperature and precipitation and the type and number of plant species six pedological zones along with representative soils are identified along the gradient 1 subantarctic forest zone podzol 2 subantarctic low tundra zone 3 subantarctic high tundra zone subantarctic brown soil without permafrost 4 antarctic sub polar desert zone subantarctic brown soil with permafrost 5 antarctic polar desert zone red ahumisol and 6 cold desert zone ahumisol zonal mineral soils in the subantarctic forest and low tundra zones are rare because large amounts of precipitation 2500 mm and cool summers have led to thick accumulation of peat whereas the processes of rubification melanization and peat accumulation decline in relative magnitude southward the processes of salinization and desert pavement formation increase in relative importance along this bioclimatic gradient carbonation and pervection silt and clay migration are maximized in the subantarctic tundra and antarctic polar desert zones because of the limited amount of land between 40 and 65 s and the presence of the antarctic convergence comparable pedogenic zones occur at lower latitudes in the southern than in the northern circumpolar region

determining soil erosion rates on semi arid watersheds using radioisotope derived sedimentation chronology this study investigates erosion dynamics of the past 90 years on three small semi arid watersheds with histories of grazing and vegetation change activity of 137cs and excess 210pb from 18 cores collected from sedimentation ponds were measured using a gamma spectrometer the sediment was dated using a constant rate of supply crs model this study represents the first time that reservoir sediment accumulation rates determined from fallout isotopes have been verified by direct volumetric measurements of aggradation based on topographic surveys measured sedimentation in the ponds ranged between 1 9 and 2 3 cm y 1 representing average sediment delivery rates from the watersheds of between 0 6 and 2 0 t ha 1 y 1 these sediment delivery rates were in agreement with those established by other methods for similar catchments in the region past variations in sedimentation rates were identified and correlated with recorded history of anthropogenic disturbance 137cs and 210pb methods are suitable for use in arid environments and can complement each other to increase reliability of erosion rate estimates the abundance of stock ponds in southwestern us presents an opportunity to quantify historic erosion and sediment transfer dynamics in areas that have not been well studied or instrumented this article is protected by copyright all rights reserved

rock glaciers in the south shetland islands western antarctica rock glaciers are found in the peripheral regions of antarctica particularly in the antarctic peninsula region study of these features is relevant for the palaeoenvironmental reconstruction of maritime antarctica because they are indicators of permafrost and periglacial conditions this paper reports and analyzes the results of an inventory of rock glaciers and protalus lobes in the south shetland islands nine rock glaciers and eleven protalus lobes have been identified all of them are located in recently deglaciated zones between 300 m a s l and sea level and they cover an area of 497 103 m2 tongue shaped rock glaciers are more common than lobate types being in general of medium and small sizes they are talus rock glaciers 55 and debris rock glaciers 45 according to the genetic classification the lack of a preferred orientation suggests that there is no significant microclimate control on their distribution they are related to particular morphodynamic situations estimated annual velocities based on relationships with raised beaches and transported debris volumes range between 2 4 and 97 cm year 1 within the ranges reported for other rock glaciers three groups of rock glaciers can be recognised a those immediate postdating the last major ice recession b rock glaciers younger than 2000 years bp but pre dating the little ice age lia and c rock glaciers formed during the lia

degradation of soil structure by welding a micromorphological study abstract in 1985 a plot study was started on sloping cultivated loess soils in south limbourg the netherlands to evaluate the effects of various cropping systems of fodder maize on runoff soil loss and crop yield under natural rainfall to monitor degradation of soil structure including crust formation undisturbed vertical samples 15 7 cm for soil micromorphological analysis were taken of the top 7 cm of soil at ten dates chosen in relation to times of tillage and sowing crop stage harvest and winter frost wheel marks if present were also sampled contrary to accepted views no disintegration of structural elements by slaking or dispersion was observed freshly tilled soil exhibited a loss of its original granular structure by coalescence of the aggregates into larger units eventually leading to a structureless state of part of the top soil processes held responsible for this are mainly welding of wet aggregates and seldom fusion by silt infillings in vertical inter aggregate pores the two layer model of soil crust formation of mcintyre could not be confirmed as no important vertical translocation of fines or washed in layers were observed horizontal cracks developed in the structureless soil giving rise to a platy structure in part of the top soil transitional stages of loss of soil structure were observed characterized by the progressive reduction of compound packing voids to vughs which ultimately disappeared completely and sometimes were replaced by planar voids besides structural crusts sedimentary crusts including splash deposits were observed

geochemistry of soils of king george island south shetland islands west antarctica implications for pedogenesis in cold polar regions fine fractions of soils on the barton peninsula king george island west antarctica have been forming during the last 6000 yr since the last deglaciation texturally they are mostly composed of mineral and rock fragments with some volcanic ashes which are also indicated by geochemical compositions representing for the nonclay silicate minerals and low values of chemical index of alteration no significant changes are observed in major and trace element abundances such geochemical characteristics suggest that chemical weathering of bedrocks on the barton peninsula seems insignificant and that the soils are composed of physically weathered mineral and rock fragments which are mixed with eolian additions of volcanic ashes and patagonian dusts chondrite normalized rare earth element ree distribution patterns of the barton peninsula soils are slightly different from those of bedrocks indicating that the ree abundances and characteristics were influenced by eolian additions mixing calculations which mass balance the rees suggest that volcanic ashes blown from deception island were the major eolian contributor followed by atmospheric dusts sourced from patagonia south america even in the warmer and humid climatic conditions in the maritime antarctic region the chemical weathering of bedrocks appears to be insignificant probably due to the relatively short duration of weathering since the last deglaciation

assessment of sediment and erosion rates by using the caesium 137 technique in a chinese polygonal karst depression karst depressions comprise geomorphologically important sources and sinks for sediments and associated pollutants yet the sedimentology of many depressions is not well understood in the world in this paper the 137cs technique was employed to estimate recent sedimentation rates in a chinese polygonal karst depression the results indicate that the sediment deposition rates ranged from 0 91 to 1 97 mm year 1 from 1963 to 2007 and the average sediment deposition rate and specific deposit yield were estimated to be 1 47 mm year 1 and 20 t km 2 year 1 respectively these results are consistent with the local monitoring data of runoff fields which confirms the validity of the overall approach this shows that the soil loss rate is very low in some karst areas of southwest china above all the approach appears to offer valuable potential to study surface erosion by estimating sediment deposition rates of karst depressions rather than the assessment of complicated soil erosion in stony soils of carbonate rock slopes in addition the space distribution of surface soil and 137cs inventories are affected remarkably by the inhomogeneous dissolution of limestone under the soil it may be an important phenomenon which exists widely in karst areas and it is significantly different from other places

variation in the characteristics and development of soils at edmonson point due to abiotic and biotic factors northern victoria land antarctica abstract the lack of baseline surveys of soil environments in many areas of antarctica provides an impediment to understanding their suitability for supporting biotic communities and limits abilities to monitor and predict impacts of environmental changes a soil survey was conducted at edmonson point victoria land within representative local environments to identify their variability and drivers of soil processes and geochemistry the soils were coarse textured and lacked cohesion and structural development the parent material was homogenous and consisted of weathered and unconsolidated basaltic lavas and scoria despite these similarities the soils varied significantly with the variation driven by local environmental and biotic factors penguins had the greatest influence deposited guano altered soil processes leading to profound changes in soil characteristics the ornithogenic soils were rich in penguin bio elements with low c n high ec and large variation in ph contents of n and c declined at comparable rates as c n values did not change with time ornithogenic p was not readily lost resulting in its high concentrations in relict soils abundant bacteria played a key role in these processes but after cessation of guano inputs bacterial numbers and activity declined considerably alternatively rich autotrophic microflora had a little influence on ornithogenic soil geochemistry characteristics and development of mineral soils were driven by hydrology and associated biological processes dry fellfield soils were the most immature as indicated by more coarse grained material neutral ph low ec and c n values scarce microflora and elemental content corresponding to typical background values alternatively soils from moss communities and wetlands had higher amounts of fine grained material c n and c n values and lower ph that resulted from accumulation of organic matter elemental concentrations in soils from moss communities were similar to those in fellfields but were elevated in wetland soils while c and n contents seemed to be controlled by biotic communities geochemistry of other elements was driven by external inputs although some inputs may originate from substratum weathering in the surrounding areas marine derived elements redistributed with penguin guano seemed to be the major source of the enrichment analyses of the origin and distribution of the soil elements may provide valuable records for reconstruction of geochemical and environmental processes in antarctic terrestrial ecosystems

spatial and temporal variations of actual soil water repellency and their influence on surface runoff the increase of surface runoff at the plot scale caused by soil water repellency is a generally accepted phenomenon however to improve the understanding of the effect of water repellency on runoff at the catchment scale spatio temporal dynamics of water repellency have to be analysed in more detail the experimental setup of this study allowed the investigation of the relationship between water repellency and runoff generation on quaternary and tertiary sandy substrates while ensuring similar conditions in terms of terrain characteristics meteorological and vegetation free conditions on both areas measurements of water drop penetration time and contact angle were carried out over a period from september 2003 to december 2005 spatial variability of actual soil water repellency was related to heterogeneity of substrate and geomorphologic units variations in time were related with the seasons and their meteorological conditions to relate variable degrees of actual water repellency to surface runoff generation both variables were measured in parallel at the plot scale 1 m 1 m and at the hillslope scale from september 2004 to december 2005 soil water repellency of the tertiary sands showed a temporal variability depending on the season with the highest degree during summer and autumn variation of hydrophobicity between the seasons caused higher runoff coefficients in summer and autumn spatial heterogeneity of the soil water repellency revealed lower values in fine textured erosion rills and higher values for interrills and top areas the measured runoff coefficients decreased from the scale of microplots to the hillslope scale due to infiltration in hydrophilic rills on the hillslope the results suggest that improved hydrological modelling approaches on water repellent soils can be based on a geomorphological subdivision of the catchment area and seasonally varying infiltration parameters copyright 2007 john wiley sons ltd

use of fallout 137cs in investigations of overbank sediment deposition on river floodplains abstract river floodplains have been recognised as important sinks for storing suspended sediment and associated contaminants mobilised from the upstream catchment however information on contemporary rates of overbank sedimentation is difficult to obtain using conventional methods measurements of the 137cs content of floodplain sediments provide an alternative approach to obtaining estimates of medium term rates ca 40 years of overbank sediment deposition the 137cs approach requires only a single site visit and minimum sample preparation furthermore it is capable of providing information on spatial patterns of sediment deposition on floodplains which is needed to improve our understanding of the processes involved in overbank flow and sediment deposition this paper reviews the basis for using 137cs measurements in floodplain sedimentation studies and presents improved procedures for interpreting 137cs profiles in floodplain sediments and for obtaining estimates of sedimentation rates from single measurements of the total 137cs inventories of bulk sediment cores the results obtained from a case study undertaken on the floodplain of the river stour dorset uk are presented

sediment yield and sources in dam controlled watersheds on the northern loess plateau abstract an improved understanding of the temporal variations in soil erosion rates and sediment sources is necessary to identify the main areas prone to soil erosion and to effectively implement soil and water conservation measures in this study we selected two dam controlled watersheds xiaoshilata and yangjiagou on the northern loess plateau china and determined the temporal variations in the sediment yield the sedimentation upstream of the dams showed that there were 31 and 9 flood couplets in the xiaoshilata 1958 1972 and yangjiagou watersheds 2007 2011 respectively which have trapped 16 5 104 t and 3 38 104 t of sediment respectively the estimated specific sediment yield was approximately 173 6 t ha a and 106 1 t ha a in the xiaoshilata and yangjiagou watersheds respectively a multivariate mixed model was applied to identify the different sediment sources the results indicated that weathered sandstone contributed approximately 61 52 of the total sediment and the remaining sediment loss was from bare loess soil 32 54 and grassland 5 94 in the xiaoshilata watershed in the yangjiagou watershed approximately 66 8 of the sediment originated from weathered sandstone whereas bare loess and grassland accounted for 17 5 and 15 7 of the sediment yield respectively based on these findings we recommend that comprehensive soil conservation measures are needed to soil erosion control for the permanent steep gullies due to high sediment contribution the sedimentation behind the check dams provides an indirect method for estimating the sediment yield in ungauged basins

use of 137cs and 210pbex measurements on deposits in a karst depression to study the erosional response of a small karst catchment in southwest china to land use change karst depressions represent important sinks for sediment and such sediment can provide a valuable record of the impact of environmental change on soil erosion rates however the sediment dynamics of karst depressions are not well understood this contribution reports a study of the small catchment of a karst depression in southwest china with a drainage area of 0 054km2 aimed at using the sediment deposits in the depression to reconstruct the erosional response of the catchment to land use change and more particularly the deforestation which took place in 1979 137cs and 210pbex are used as both chronometers and as tracers five cores collected from the bottom of a depression with an area of 2652m2 showed similar 137cs depth distributions with a single 137cs peak which was attributed to the 1979 deforestation the 137cs activity associated with the peaks varied between 5 68 0 64 and 9 19 0 99bqkg1 the average depth of sediment deposition between 1979 and 2008 deduced from the depths of the 1979 137cs peak was 74 1cm the existence of relatively high 210pbex activity of 66 33 8 44bqkg1 in the upper section 016cm of the core analyzed for 210pbex suggests that recent sedimentation has been very limited net erosion rates on the hillslopes contributing runoff and sediment t to the depression were estimated to be 5258tkm2year1 from 1979 to 1990 and 256tkm2year1 from 1991 to 2008 respectively the high sediment yield in the first period was associated with the severe soil erosion triggered by the 1979 deforestation which resulted from the changes in land ownership immediately after the cultural revolution soil erosion has been very limited since 1990 because the thin soils had been totally removed from many parts of the karst slopes and the soils remaining on the other parts of the slopes have been protected by terracing or vegetation rehabilitation copyright c 2012 john wiley sons ltd

three decades of dating recent sediments by fallout radionuclides a review this paper reviews the 210pb dating programme carried out at the university of liverpool over a period of three decades since its inception by frank oldfield in the mid 1970s the work at liverpool

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

post caldera evolution of deception island bransfield strait antarctica over holocene timescales abstract the study of palaeoclimatic changes in fast warming regions can contribute to the understanding of the forcing mechanisms responsible for the global changes that are presently happening deception is an active volcanic island in the bransfield basin that has a complex history strongly influenced by both magmatic and tectonic processes however without accurate information on the distribution of melt depth of sediments and holocene timescales of its volcanic eruptions the models for the post caldera evolution of deception island are poorly constrained although this region has undergone severe environmental changes due to recent eruptions hindering the location of potential study areas of paleo volcanic eruptions it is still possible to reconstruct post caldera evolution at a local scale employing analyses such as radiocarbon dating stable carbon and nitrogen isotopic compositions and particle size distributions in subsoil horizons we have studied the coastal areas of whalers bay and between wensleydale beacon and cross hill to identify the major periods of alluvial sedimentation on deception island whalers bay was influenced by a large amount of moving water generated by ice melting the coastal location of both sampling sites contributes to preserve the sedimentation history in their soil profiles despite the severe environmental changes due to recent eruptions our findings indicate that from approximately 13 to 5 cal kyr bp the accumulation of organic matter was stable and the landforms were not altered after that time post caldera eruptions occurred melting the glacier and consequently flooding surficial soil layers with mud these changes are consistent with old 14 c ages for subsoil organic matter and therefore with the occurrence of intense cryogenic disturbance processes

effect of antecedent soil moisture on preferential flow in a texture contrast soil summary the effect of soil moisture status on preferential flow in a texture contrast soil was investigated by applying 25 mm brilliant blue dye tracer to soil profiles at high and low antecedent soil moisture differences in soil morphology and chemistry between soil profiles had little effect on the depth of dye infiltration and dye distribution down the profile antecedent soil moisture strongly influenced the type depth and rate of dye tracer movement in the wet treatment the dye tracer infiltrated to depths between 0 24 and 0 40 m at an average rate of 120 mm h 1 whilst in the dry treatment the same volume of dye tracer infiltrated to between 0 85 and 1 19 m depth at an average rate of 1160 mm h 1 in dry antecedent conditions finger flow developed in the a1 horizon as a result of water repellency in the wet treatment the wetting front developed permutations but did not break into fingers despite similar particle size distributions flow in the a2 e was slower than the a1 horizon due to the absence of macropores in the dry treatment the dye tracer ponded on the upper surface of the b21 horizon which then spilled down the sides of the large clay columns as rivulets at rates of between 2000 and 3000 mm h 1 the dye tracer accumulated at the base of the columns resulting in backfilling of the inter column shrinkage cracks at an estimated rate of 750 mm h 1 in the subsoil water movement occurred via shrinkage cracks which resulted in flow by passing 99 of the soil matrix in the b21 horizon and 94 of the soil matrix in the b22 horizon evidence of rapid and deep infiltration in dry texture contrast soils has implications for water and solute management this knowledge could be used to i improve irrigation and fertilizer efficiency ii explain variations in crop yield iii reduce salinity through improved leaching practices iv reduce the risk of agrochemicals contaminating shallow groundwater

advances in permafrost and periglacial research in antarctica a review recently the research on permafrost periglacial morphology and processes had a great stimulus especially from the international polar year permafrost areas of continental antarctica with its extreme dry and cold environment can be considered an analog of extraterrestrial landscapes like those on mars but also preserve much paleoclimatic information of this crucial part of the global climatic system on the other hand maritime antarctica is one of the areas of the world currently affected by the greatest air warming and provides a unique opportunity to understand the impacts of climate change on permafrost and its related ecosystems despite the significant recent progress some gaps on permafrost distribution still remain as the network for permafrost and active layer monitoring needs further enlargement and better standardization ground ice its age and stability over time need further investigation as well as the role of living organisms on the weathering processes within the cryotic rocks the landscape evolution of continental antartica could be improved providing potential implications also for a better understanding and modeling of life and landscape evolution of other planets

soil formation in wright valley antarctica since the late neogene abstract we investigated over 180 soil profiles on 15 drift units ranging from recent to pliocene or older in age in wright valley antarctica the drifts originate from 1 post valley cutting by an advance of the east antarctic ice sheet 2 advances of the wright lower glacier from grounding of ice in the ross embayment and 3 advance of alpine glaciers along the south valley wall holocene and lgm soils lack staining from oxidation of iron bearing minerals and visible salts contain ice or ice cemented permafrost in the upper 0 5 m and are classified as glacic or typic haploturbels other soils of late quaternary age are stained to 2 in the upper 70 cm of profile and are classified as typic haploturbels soils of mid late quaternary age are stained to 20 cm have ice cemented permafrost at depths in excess of 1 m and stage 2 salts flecks and patches covering 2 and are classified as typic anhyorthels soils of early quaternary to late pliocene age are oxidized to depths 30 cm have stage 3 salts flecks and patches covering 20 of the profile face contain 4000 4200 mg salts cm 2 and are classified as salic anhyorthels soils of pliocene age are deeply oxidized 50 cm have stage 5 6 salts strongly cemented or indurated salt pans contain 5000 7000 mg salts cm 2 and are classified as petrosalic anhyorthels soils of early pliocene or older age do not show the degree of development of younger soils because they are derived from peleus till which contains highly erosive fine sandy quartz rich rock our data question the notion of high level antarctic lakes occupying most of the valley during the lgm and early holocene

enhanced bedrock weathering in association with late lying snowpatches evidence from livingston island antarctica an indication of the extent of weathering on different aspects of rock outcrops on livingston island antarctica was obtained by means of a schmidt hammer a cone indenter and measurement of weathering rind thickness results show that weathering particularly chemical weathering is enhanced on the lee side of outcrops where snow accumulates as a result of prolonged wetting by the melting snow rock moisture and temperature data indicate that the south facing snow accumulation side of obstacles have high rock moisture levels and maintain relatively high temperatures whilst chemical weathering is greater on the leeward side of outcrops mechanical processes are greater on the windward side the presence of late lying snow thus appears to exert a strong influence on weathering

variation in water content and wetting patterns in dutch water repellent peaty clay and clayey peat soils abstract the variation in water content of grass covered peaty clay and clayey peat soils was studied at six sites in the netherlands the topsoils were water repellent during dry spells when the topsoils were dry they could only absorb water with difficulty which is illustrated by wetting rate measurements precipitation could flow rapidly through shrinkage cracks towards the subsoil bypassing the matrix of the peat however the measurements revealed that preferential flow was not limited to macropore flow irregular fingerlike wetting patterns were also formed in the soil matrix due to these typical wetting patterns soil water content varied over short distances at all sites at all sampling dates

properties and processes of recently established soils from deglaciation of cierva point western antarctic peninsula abstract for more than sixty years the antarctic peninsula has experienced significant temperature increases that have accelerated glacial retreat glacial losses along with the relatively warm and moist climatic conditions of the region have increased the rate of soil development the objective of this study is to study the properties and genesis of soils at cierva point which is located in the zone of maximum warming along the western antarctic peninsula cierva point is a terraced steeply sloping ice free peninsula containing a small retreating glacier the peninsula contains a large penguin rookery and significant areas of moss buildup twenty seven soils were described physical and chemical properties from each horizon were analyzed four categories of soil were identified acidic ph 5 moss dominated high organic matter accumulations and ornithogenic high phosphorus accumulations neutral soils were newly formed soils which had undergone the least development and were located closest to the glacier margin acidic soils were located farthest from the glacier margin allowing for a greater nutrient leaching to occur these soils have extremely low ph values as low as 3 5 but did not have the high phosphorus accumulations found in ornithogenic soils or the high soil carbon content found in moss dominated soils in a region with rapidly retreating glaciers such as the antarctic peninsula proximity to the glacier margin becomes an important factor determining soil properties soils farther from the glacier have had more time to be affected by leaching penguin activity and moss buildup

periglacial processes and landforms in the south shetland islands northern antarctic peninsula region abstract periglacial processes and landforms together with the presence of permafrost are among the most relevant geomorphological elements in the northern antarctic peninsula region their distribution affects the hydrology and has consequences for the ecosystems of the ice free areas in this paper a compilation of the different types of periglacial landforms and processes occurring in the south shetland islands is carried out and their spatial distribution is analysed furthermore the relationships of the periglacial landforms with local conditions and permafrost distribution have been taken into account a total of thirty three types of periglacial landforms were identified and considered in this work patterned ground and stone fields are the most common periglacial landforms which are located within a wide altitudinal range and mainly on platforms field studies aerial photograph and satellite imagery interpretation were implemented to produce detailed maps from ten areas with different geological geomorphological and relief characteristics including the largest and most relevant ice free areas within the archipelago showing the presence and spatial distribution of periglacial landforms this work shows that the periglacial environment primarily conditioned by the regional climatic conditions has a great diversity in the studied region and that the distribution of the periglacial landforms is also related to local relief and geomorphological characteristics lithology hydrogeology and presence of permafrost where altitude plays an important role periglacial phenomena are widespread above 10 m a s l and are especially active on slopes and platforms between 30 and 100 m a s l the spatial distribution of periglacial landforms helps to identify the presence of permafrost that is dominant above 25 30 m a s l and more than 70 of the surface is occupied by active layer related landforms