late pleistocene glaciation of the kosciuszko massif snowy mountains australia abstract late pleistocene glaciation of the australian mainland was restricted to a small area of the southeastern highlands geomorphic mapping of the area and exposure dating using the in situ produced cosmogenic isotope 10be provides evidence for at least two distinct glaciations the early kosciuszko glaciation consisted of a single glacier advance before 59 300 5400 years ago snowy river advance the late kosciuszko glaciation comprised three glacier advances 32 000 2500 headley tarn advance 19 100 1600 blue lake advance and 16 800 1400 years ago mt twynam advance the early kosciuszko glaciation was the most extensive and the late kosciuszko advances were progressively less extensive these periods of glaciation in the highlands correspond to episodes of periglacial activity and peaks in lake levels and river discharge at lower elevations in southeastern australia glacier advances on the kosciuszko massif correlate with advances in tasmania south america and new zealand and are broadly representative of hemispheric climate changes during the last glacial cycle

palaeoenvironmental change recorded in the palaeodunefields of the western murray basin south australia new data from single grain osl dating this study is concerned with the reconstruction of the palaeoenvironmental history of southeastern australia for the last 300 ka by establishing a luminescence chronology of dune sand deposition in the western murray basin south australia in the study area vast fields of palaeodunes stabilised by vegetation provide evidence of past environmental change in total 98 samples were collected from dune sand layers at 13 different dune sections the time of their deposition was determined using optically stimulated luminescence dating of single quartz grains accounting for the impact of post depositional mixing by the use of a finite mixture model the oldest depositional phase demonstrates that dune sand layers of great antiquity are preserved in the western murray basin ranging up to at least 380 ka phases of substantial dune sand deposition were identified for the periods 18 38 ka and 63 72 ka older depositional phases also exist but are poorly resolved due to relatively large errors of the luminescence ages aeolian deposition during the last termination and the holocene is relatively limited with a slight clustering of ages at the time of the antarctic cold reversal and from 5 8 ka two modern ages give evidence of very recent dune sand deposition comparison with other palaeoclimate records from the region suggests that phases with high aeolian sedimentation coincide with more arid conditions and breaks in the dune record with more humid phases thus although dune records are often discontinuous and their interpretation in palaeoclimatic terms is not always straightforward the palaeodunes of the western murray basin show a good preservation of phases of aeolian activity and provide useful information for palaeoenvironmental reconstruction

last glacial to holocene evolution of semi arid rangelands in southeastern australia pollen sequences from playa lakes in the darling anabranch dunefields of southwestern new south wales record vegetation changes over the last glacial period and into the holocene this interval was one of marked taxonomic and structural reorganization with the plant communities that became established after the last glacial maximum lgm 24 18 ka distinct from those that had prevailed over the build up to full glacial conditions 70 24 ka the glacial period was characterized by a gradual reduction of woodland and tall shrubland cover recolonization of the dunefields involved a similar gradual succession from herbfields and low shrublands to tall shrublands and finally woodlands these changes are likely to have been driven by climatic change particularly fluctuations in temperature precipitation and atmospheric co2 as global climate systems entered and emerged from the last glaciation

a charcoal rich horizon at o69 greenland evidence for vegetation burning during the norse landnam it is often assumed that the colonisation of greenland by norse settlers in c a d 985 had a sudden and dramatic effect on the environment involving substantial vegetation clearance and environmental degradation consequently it has been argued that charcoal rich horizons visible in many sections in greenland represent the initial burning of the vegetation by norse farmers to create land suitable for agriculture in this study a charcoal rich layer visible in a modern drainage ditch beside the norse farm of o69 was analysed using archaeobotany sedimentary analysis and radiocarbon dating to test the date and formation processes of the horizon it is demonstrated that the charcoal rich layer at o69 was not derived from in situ vegetation burning in the 10th century and concluded that the layer was probably formed by the addition of midden material to the infields around o69 in the 13th and 14th centuries cal ad perhaps as part of a soil amendment strategy it is argued that caution must be exercised when interpreting charcoal rich horizons as time specific chronological markers in palaeoenvironmental sequences in greenland

lateral migration thermoluminescence chronology and colour variation of longitudinal dunes near birdsville in the simpson desert central australia the longitudinal dunes of the simpson desert in the vicinity of birdsville have been reworked largely during the holocene from dunes deposited up to 80000 years ago or earlier the widespread asymmetry of these roughly northward trending dunes with steeper eastern faces and more gentle western faces supports wind rose data showing sand transporting winds from the southwest obliquely intersecting the dunes while this suggests a change in the wind pattern since the dune field was oriented it does not indicate that the dunes are necessarily shifting leeward eastward as a consequence it is hypothesized that the direction of migration is controlled by the extent to which the dunes are vegetated relatively well vegetated dunes can accrete sand on their gentle stoss slopes and erode on their lee slopes causing them to shift westward and hence obliquely into the wind a condition that probably prevails in wetter regions and during episodes of relatively humid climate in contrast in very dry areas or during arid phases sand can move unimpeded up a sparsely vegetated stoss face and over the crest to form an avalanche or slip face on the lee side thereby causing the dunes to shift eastward despite evidence that longitudinal dune crests can shift laterally to some extent the dunes in the western part of the simpson desert have not migrated either westward or eastward more than 100m or so from their pleistocene cores aeolian transport and partial or complete removal of iron cutans from around quartz grains results in dunes of widely varying colour yet of similar age

late quaternary linear dune accumulation and chronostratigraphy of the southwestern kalahari implications for aeolian palaeoclimatic reconstructions and predictions of future dynamics abstract the linear dunes of the kalahari now largely inactive have long been identified as having potential palaeoenvironmental significance the application of optically stimulated luminescence osl dating to these dunes in the 1990s provided the first chronology of aeolian accumulation in this region though field methodologies and time consuming multiple aliquot laboratory protocols limited both the depth of sampling in dune bodies and the total number of samples dated in order to permit a more thorough investigation of the potential of these dunes to preserve long chronological records this intensive study presents 71 osl ages from the linear dunes of the southwestern kalahari at witpan south africa sampled with coring equipment at regular and frequent intervals down to bedrock the earliest sand accumulation recorded at witpan is at 104 ka and in spatially discrete locations other evidence of dune activity is recorded at 77 76 57 52 and 35 27 ka although an inherently discontinuous archive the linear dunes of the southwestern kalahari have the potential to record multiple phases of dune construction following the last glacial maximum there is near continuous evidence of dune building with a peak of accumulation recorded from 15 to 9 ka at five individual sites this latter period is generally recognised from other proxy evidence as being unusually arid in this region and such periods of dune activity are likely to be related to intensification of the continental anticyclone during the holocene accumulation has continued at most sites sampled albeit at a lesser intensity this may imply that these dunes are presently not far from thresholds of activation

the two step shape and timing of the last deglaciation in antarctica the two step character of the last deglaciation is well recognized in western europe in greenland and in the north atlantic for example in greenland a gradual temperature decrease started at the bolling b around 14 5 ky bp spanned through the allerod a and was followed by the cold younger dryas yd event which terminated abruptly around 11 5 ky bp recent results suggest that this ba yd sequence may have extended throughout all the northern hemisphere but the evidence of a late transition cooling is still poor for the southern hemisphere here we present a detailed isotopic record analyzed in a new ice core drilled at dome b in east antarctica that fully demonstrates the existence of an antarctic cold reversal acr these results suggest that the two step shape of the last deglaciation has a worldwide character but they also point to noticeable interhemispheric differences thus the coldest part of the acr which shows a temperature drop about three times weaker than that recorded during the yd in greenland may have preceded the yd antarctica did not experienced abrupt changes and the two warming periods started there before they started in greenland the links between southern and northern hemisphere climates throughout this period are discussed in the light of additional information derived from the antarctic dust record

the record of continental dust from australia in tasman sea sediments abstract the flux of aeolian dust from australia to sediments of the tasman sea has increased during glacial stages of the last four glacial cycles low fluxes of dust from australia before 350 ka were followed by an increase in stage 10 and high fluxes in peak glacial periods thereafter the initiation of higher dust fluxes in stage 10 is consisten with previous estimates of the age of onset of aridity in the source area dust flux to the tasman sea is thought to record the intensity of deflation from the source area in interior southeastern australia which was marked by arid conditions and possibly greater windiness during the last glacial a transect of five cores from the central tasman sea revealed consistently low dust fluxes north of 33 s increasing southward to approximately 40 s glacial to interglacial movement of the northern boundary of the dust plume governed by the position of the subtropical ridge was less than 6 latitude probably closer to 3 350 km the position of the dust plume determined in this study and its response to climate change are significantly different from a previous reconstruction based on the measurement of quartz content of the non biogenic sediment fraction

the age of the palaeodunefield of the northern murray basin in south australia preliminary results abstract a vast field of old desert dunes extends from northwestern eyre peninsula across yorke peninsula and the northern adelaide plains into the murray basin and northwestern victoria there are patches of parabolic forms but the sand ridges under review are of seif linear or longitudinal type they trend nw se in the west and west east in the east here we record luminescence dates for three dune sites in the waikerie district of the northwestern murray basin they range from respectively 151 25 3 ka 157 33 3 ka and a basal age of 59 6 ka with sand movement also indicated around 1906 and 1933 ce apart from the last named no unconformities are discernible in the sampled sections

palaeomagnetic stratigraphy of lake bungunnia plio pleistocene precursor of aridity in the murray basin southeastern australia abstract the murray darling river system in southeastern australia formerly flowed into a large lake lake bungunnia before reaching the sea fine grained clastics of this system the blanchetown clay formation extend over an area of about 68 000 km2 underlying the mallee region with its surface array of dunes and salt lakes palaeomagnetic analyses are used to date the major hydrologic transition from the expansive freshwater system to the saline deflation playas and dunes that characterize this landscape today two sites were selected for sampling one a cliff section on the left bank of the murray river at chowilla the other from within sediments of lake tyrrell a saline playa cut into sediments of the older freshwater system two sequences were sampled at tyrrell one by coring to 30 m in the basin centre the other a composite cliff and 5 m core on the western margin of the playa post bungunnia sediments representing modern landforms were sampled in both surficial dune palaeosol units of the woorinen formation and in saline sediments the tyrrell beds within the modern saline playa the sequence of multiple aeolian units of the woorinen formation and gypseous sediments of the tyrrell beds are normally magnetized indicating deposition within the past 0 7 million years by contrast the uppermost horizons of bedded blanchetown clay below a surface zone of pedogenic alteration are reversed the brunhes matuyama b m boundary key to the age of draining of lake bungunnia by deepening the overflow channel to the sea is obscured within the zone of pedogenesis separating unaltered blanchetown clays from overlying aeolian deposits the onset of aeolian and saline gypseous deposits characteristic of the arid zone facies is placed soon after the b m boundary about 500 000 years ago sequences through the blanchetown clay pass down through the matuyama reversed chron into the gauss normal chron with the lowermost section on the tyrrell west bank recording a basal reversed zone of possible gilbert age thus the origins of lake bungunnia extend back beyond basal pleistocene into the late pliocene the lake s duration covers more than 2 million years spanning the plio pleistocene boundary in this important region of southeastern australia

luminescence dating at the archaeological and human burial site at roonka south australia abstract roonka the aboriginal habitation and burial site on the river murray south australia was excavated from 1968 to 1983 in 1983 thermoluminescence tl ages were obtained for several fireplaces at the east bank site sandy dune sediments collected from east bank were also analysed using traditional tl methods and ages were found at depths down to the base at 2 6 m now 20 years on with optical dating methods well established it seemed instructive to repeat the measurements using new techniques specifically the single aliquot regeneration dose protocol this has provided confirmation of the tl ages and provided an age framework for both the archaeological and geological aspects of roonka the ages confirm the archaeological description of the structure of the dune and show that only the top 20 is the holocene bunyip formation the lower part is assigned to the woorinen formation formed during and after the last glacial maximum burials at east bank took place between about 16 and 20 ka substantially earlier than those on the roonka flat but consistent with the earliest evidence of occupation on the flat they are one of the very few securely dated pleistocene burials in australia whether the individuals were gracile or robust is not known

500 ka precipitation record from southeastern australia evidence for interglacial relative aridity 230 th 234 u dating of speleothems from southeastern australia documents changes in effective precipitation over the past 500 k y at a temporal resolution not previously achieved results show that the highest effective precipitation for the southeastern interior of australia occurred during stadials and cool interstadials of the past four glacial cycles interglacials and warm interstadials as well as glacial maxima are comparatively arid we suggest that lower regional temperatures over the continent and changes in atmospheric circulation stronger walker circulation produced the observed periods of increased effective precipitation

palaeoecological and historical evidence for manuring and irrigation at garðar igaliku norse eastern settlement greenland palaeoenvironmental data are presented from the site of gar ar modern igaliku the location of the cathedral and the bishop s farm in the norse eastern settlement of greenland the latter was founded from c ad 985 and abandoned some time during the fifteenth century inspection of drainage ditches located in close proximity to the settlement ruins revealed inter alia an organic rich unit containing cultural debris worked wood animal bone stone and charcoal dated by ams radiocarbon dates on seeds to the period c ad 1110 1370 fossil insect and pollen assemblages contained within the deposit appear representative of natural environments primarily wet eutrophic meadows but are mixed with high frequencies of a range of synanthropic insects including human and animal ectoparasites that could only derive from indoor habitats this is strongly indicative of the manuring of fields with waste from houses and byres in order to increase yields of hay large amounts of hay would have been necessary to prov

last glacial megafaunal death assemblage and early human occupation at lake menindee southeastern australia abstract the tedford subfossil locality at lake menindee preserves a diverse assemblage of marsupials monotremes and placental rodents of the 38 mammal taxa recorded at the site almost a third are of extinct megafauna some of the bones are articulated or semi articulated and include almost complete skeletons indicating that aeolian sediments rapidly buried the animals following death new optical ages show the site dates to the early part of the last glacial 55 700 1300 yr weighted mean age this is close to the 51 200 39 800 yr australia wide extinction age for megafauna suggested by roberts et al 2001 science 292 1888 1892 but like all previous researchers we cannot conclusively determine whether humans were implicated in the deaths of the animals although an intrusive hearth at the site dating to 45 100 1400 yr ago is the oldest evidence of human occupation of the darling river no artifacts were identified in situ within the sub fossil bearing unit non anthropogenic causes such as natural senescence or ecosystem stress due to climatic aridity probably explain the mortality of the faunal assemblage at lake menindee

lake bungunnia a plio pleistocene megalake in southern australia abstract between 2 5 ma and 0 7 ma a plio pleistocene megalake lake bungunnia existed in the western murray basin australia study of hydrologic and geologic constraints on this lake has enabled the climate of southeastern australia during the late pliocene and early pleistocene to be partly quantified modelling shows that lake bungunnia could not exist under current climatic conditions and that an average rainfall of at least 500 mm yr 1 over the catchment of the murray darling river system was likely considerably more than at present minor changes in climate caused large fluctuations in the shoreline of the shallow lake which are reflected in the geologic record possible histories for lake bungunnia are suggested in the light of this evidence demise of the megalake heralded the onset of aridity in southern australia and modern landforms date from that time salt lakes in part of the western murray basin may have directly descended from lake bungunnia

environmental responses of past and recent agropastoral activities on south greenlandic ecosystems through molecular biomarkers paleoenvironmental studies previously performed on lake igaliku revealed two agropastoral phases in south greenland the norse settlement from ad 986 to ca ad 1450 and the recent installation of sheep farmers since the 1920s to improve the knowledge of the timing and magnitude of the greenlandic agropastoral activities a lipid inventory was realized and compared with biological and geochemical data during the 12th century a major increase in deoxycholic acid doc and coprophilous fungal spores revealed a maximum of herbivores synchronously a minimum of the n c29 n c31 alkane ratio and tree and shrub pollen and a maximum of triterpenyl acetates showed a reduction in the tree and shrub cover because of grazing activities lupanone produced by angiosperms appeared simultaneously in the molecular content probably revealing an introduction of plant species by the norse as it has been the case for rumex spp no major erosion was recorded by trimethyl tetrahydrocrysenes tthcs and titanium ti fl

problematic but promising ponds palaeoenvironmental evidence from the norse eastern settlement of greenland pollen and related proxy based studies of human environment interactions during the norse and later periods within greenland have primarily involved the investigation of peat lake and soil deposits all of which have taphonomic and sampling problems many small ponds exist but they seem to have been relatively ignored in investigations of palaeoecologically based environmental history to evaluate their usefulness for studies of ecologically related cultural history especially where sites are in intimate association with the archaeology a pond in the norse eastern settlement has been examined to investigate three principal questions i does such a site contain a useful record of environmental history ii does it offer a record of sufficient resolution and sensitivity for the study of anthropogenic landscape impacts iii are there any apparent drawbacks to these sequences using data obtained from palynological diatom sedimentological and radiocarbon analyses it is concluded that environmental data for each proxy aside from 14c dating are clearly capable of being explained in a reasonably straightforward and compatible manner and fulfil the hopes for the sampling medium copyright 2011 john wiley sons ltd

evaluating the use of dune sediments as a proxy for palaeo aridity a southern african case study abstract the dominance of dryland environments in the southern hemisphere makes the study of these regions of critical importance for the development of regional hemispheric and global models of environmental change unfortunately the wetting and drying cycles associated with semi hyperarid climates are not conducive to the preservation of traditional organic proxy data sources the last decade however has seen the development of a number of alternative archives including the application of luminescence dating techniques to dunes and other aeolian deposits in continental situations the existence of relict dune fields has long been thought to be evidence of drier conditions during the pleistocene and direct ages from these features have been interpreted almost exclusively as indicating phases of aridity however an increasing number of ages from a broader range of environments are calling into question the assumption that aeolian activity can be simply equated with aridity presented here is a comparison of dune ages that have been obtained from across southern africa with a range of proxies from both terrestrial and marine records taken as a whole three primary phases of activity can be identified at 60 40 35 20 and 17 4 ka the frequent discordance with other terrestrial records indicating coeval increases in humidity and the close correlation of these phases with wind strength proxies suggest that aridity is unlikely to be the sole or even primary forcing mechanism for aeolian activity in the region and the palaeoclimatic significance of these sedimentary archives needs to be reassessed

understanding linear dune chronologies insights from a simple accumulation model abstract dunefields are today often found in regions where environmental conditions are no longer conducive to widespread aeolian transport and deposition and are thus seen as potential archives of palaeoenvironmental information some dune types are more suitable for this purpose than others and linear dunes used here synonymously with longitudinal dunes have been most frequently employed they are commonly found in dryland and dryland marginal regions and they are apparently less migratory than some other dune forms thereby offering the potential for longer environmental histories most recent studies have employed optical osl dating surveys which directly date the emplacement of dune sands to attempt to produce a representative history of aeolian accumulation at a dunefield scale yet such studies have not always given due consideration to the geomorphology of linear dune accumulation although linear dunes do not rework their sand as readily as say barchans dunes it is clear that sand deposited during an aeolian event is likely to have been removed from elsewhere on the dunefield s surface for this reason all dune archives must be assumed to be discontinuous over long timescales the effect of sediment redistribution on dune preservation and thus palaeoenvironmental interpretation is difficult to observe and poorly understood we present a simplified probabilistic model to replicate deposition erosion of sand at a linear dune crest thus simulating the type of profile sampled in many field studies in order to produce a local accumulation history the modelled sand flux incorporates various feedbacks and the simulations are run with varying boundary conditions in which the simulated surface is assumed to be in equilibrium over the multi millennial timescales of the model s duration periodic instabilities in the landscape are generally well recorded by the modelled dune accumulation history particularly when the events involve the system as a whole briefly functioning out of an equilibrium state i e the probabilities of deposition and reworking are not equal however under forcing conditions where the probabilities are unchanged throughout the duration of the model run the results can show apparent structure within the data when sample sizes are low although at large sample sizes the preservation potential decays with burial age according to a power law the model confirms the importance of rigorous sampling strategies for such studies but also suggests that if such precautions are taken the reworking inherent to linear dune aeolian systems does not preclude their use as a quaternary palaeoenvironmental archive of environmental change

breaking the waves human use of marine bivalves in a microtidal range coast during the upper pleistocene and the early holocene vestibulo chamber nerja cave malaga southern spain abstract this paper presents the results obtained from the study of the bivalves recovered during the archaeological excavations in the vestibulo chamber of nerja cave malaga southern spain carried out by professor francisco jorda cerda between 1983 and 1987 these excavations recovered the archaeological record of the sequence from the gravettian to the neolithic the mollusc remains from the vestibulo chamber of nerja cave record constitute an extraordinary collection composed of more than 136000 specimens which correspond to more than 78 kg in this work only marine bivalves were studied the bivalve remains are more than 124000 specimens corresponding to more than 65 kg from 31 taxa more than 115000 of these specimens 59 kg are derived from the shell midden dated to gs 1 the archaeological record of nerja cave is distinguished by the abundant presence of human provided marine and continental molluscs with a high presence of bivalves marine bivalves increased clearly from the lgm to the mid holocene and the human inhabitants of the cave accumulated an important shell midden in the contact between mis 2 and mis 1

aeolian fluvial interaction evidence for late quaternary channel change and wind rift linear dune formation in the northwestern simpson desert australia in central australia the most easterly extent of the macdonnell ranges border the simpson desert dunefield where widely spaced strike ridges intercept and isolate pockets of broad crested linear dunes that reflect regional changes in late quaternary climate flow regime and channel avulsion an energetic todd river reworked the eastern part of camel flat basin from 75 65 ka until the last glacial maximum lgm when it shifted eastwards but with some flows persisting through the basin until about 10 ka resulting desert surfaces of different age facilitate temporal comparisons of linear dune formation fine grained red dunes 75 65 ka in age occur on the western floor of the basin and are ramped against the foot slopes of the range after the lgm and especially during the holocene the river s departure enabled small pale coloured closely spaced coarser textured linear dunes to form on the abandoned floodplain in the eastern basin their orientation 20 farther west than the larger and older red dunes this realignment indicates that the australian wind whorl shifted southwards some 160 km or 1 5 after the lgm linear dunes in the northwestern simpson desert were formed by wind rifting involving vertical accretion of sand from a proximal source not by long distance sand transport with linear extension the blocking ranges have caused negligible downwind sediment accumulation over the past 75 ka

shifts in oceanic and atmospheric boundaries in the tasman sea southwest pacific during the late pleistocene evidence from organic carbon and lithogenic fluxes abstract the fluctuation in primary production and mineral dust accumulation was estimated to better understand marine and terrestrial environments in the tasman sea southwest pacific during the late pleistocene maxima in primary production were observed during late oxygen isotope stage ois 2 middle ois 4 and late ois 6 for core ngc 97 while minimum values were observed in ois 5 on the other hand primary production was low and relatively uniform in cores ngc 100 and 99 during the last 180 kyr these results suggest that the tasman front existed between ngc 99 30 s and ngc 97 35 s during the last 180 kyr and migrated northward by a few degree 2 3 latitude in ois 2 and 4 the mass accumulation rates mars of mineral aerosol mar aerosol estimated from the al concentration increased southward during each ois excluding ois 2 in cores ngc 100 and 99 the mar aerosol was more enhanced during glacials than interglacials in cores ngc 100 and 97 while ngc 99 showed no definite fluctuation these results suggest small northward shifts 2 3 latitude of the high pressure subtropical ridge dividing the tropical easterly circulation from the mid latitude westerlies took place during glacial times these results demonstrate that the boundary between subtropical and temperate features in both ocean and atmosphere consistently migrated by a few degrees between glacials and interglacials in addition profiles of mar of organic carbon biogenic opal and primary productivity were quite similar for cores ngc 97 and s2612 32 19 84 n 157 51 00 e which shows that the boreal and austral transition zones between subtropical and subarctic waters migrated almost synchronously along the latitudinal transect around 160 e during the last 150 kyr kawahata et al j oceanogr 55 1999 521 532 therefore boreal and austral mid latitudes could have probably experienced similar fluctuations in the oceanic and atmospheric environments

a 2500 year record of natural and anthropogenic soil erosion in south greenland the environmental impact of the norse landnam in greenland has been studied extensively but to date no study has quantified the soil erosion that norse agricultural practices are believed to have caused to resolve this problem a high resolution sedimentary record from lake igaliku in south greenland is used to quantitatively reconstruct 2500 years of soil erosion driven by climate and historical land use an accurate chronology allows for the estimation of detritic fluxes and their uncertainties land clearance and the introduction of grazing livestock by the norse around 1010 ad caused an acceleration of soil erosion up to 8 mm century in 1180 ad which is two fold higher than the natural pre landnam background from 1335 ad to the end of the norse eastern settlement in the mid fifteenth century the vegetation began to recover from initial disturbance and soil erosion decreased after an initial phase of modern sheep breeding similar to the medieval one the mechanization of agriculture in the 1980s caused an unprecedented soil erosion rate of up to 21 mm century five times the pre anthropogenic levels independently a suite of biological and geochemical proxies including ti and diatom concentrations c n ratio 13c and 15n of organic matter confirm that the medieval and modern anthropogenic erosion far exceeds any natural erosion over the last 2500 years our findings question the veracity of the catastrophic scenario of overgrazing and land degradation considered to have been the major factor responsible for norse settlement demise they also shed light on the sustainability of modern practices and their consequences for the future of agriculture in greenland