fossils from quaternary fluvial archives sources of biostratigraphical biogeographical and palaeoclimatic evidence fluvial sedimentary archives have the potential to preserve a wide variety of palaeontological evidence ranging from robust bones and teeth found in coarse gravel aggradations to delicate insect remains and plant macrofossils from fine grained deposits over the last decade advances in quaternary biostratigraphy based on vertebrate and invertebrate fossils primarily mammals and molluscs have been made in many parts of the world resulting in improved relative chronologies for fluviatile sequences complementary fossil groups such as insects ostracods and plant macrofossils are also increasingly used in multi proxy palaeoclimatic and palaeoenvironmental reconstructions allowing direct comparison of the climates and environments that prevailed at different times across widely separated regions this paper reviews these topics on a regional basis with an emphasis on the latest published information and represents an update to the 2007 review compiled by the flag inspired igcp 449 biostratigraphy subgroup disparities in the level of detail available for different regions can largely be attributed to varying potential for preservation of fossil material which is especially poor in areas of non calcareous bedrock but to some extent also reflect research priorities in different parts of the world recognition of the value of biostratigraphical and palaeoclimatic frameworks which have been refined over many decades in the core regions for such research particularly for the late middle and late pleistocene of nw europe has focussed attention on the need to accumulate similar palaeontological datasets in areas lacking such long research histories although the emerging datasets from these understudied regions currently allow only tentative conclusions to be drawn they represent an important stage in the development of independent biostratigraphical and palaeoenvironmental schemes which can then be compared and contrasted

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

sediment dates with implications for the age of the conversion from palaeochannel to modern fluvial activity on the murray river and tributaries abstract dates for sediment deposition have been obtained for a number of abandoned channels with modern features on the upper murray kiewa ovens and goulburn rivers and from palaeochannel deposits on the upper murray river just west of albury the dates from modern channels on the upper murray are problematic but suggest modern fluvial activity had begun by 5 9 ka two dates from the ovens and kiewa rivers are in agreement with this west of albury a palaeochannel point bar returned an age of 7 4 11 6 ka and a source bordering sand dune 22 5 ka sand beneath the floodplain near albury was aged 7 3 ka and was not deposited at the same time as underlying gravels where two embedded trees returned ages of 12 ka it therefore cannot be established if the sand deposit was associated with either modern or palaeochannel activity therefore on the upper murray river the transition from palaeochannel to modern fluvial activity most likely occurred between 7 and 10 ka in contrast two dates from an abandoned channel on the goulburn river indicates that modern channels were active on this river before 11 13 ka this suggests that palaeochannels were active later on the upper murray than on the goulburn river and compared with previous work possibly later than on the murrumbidgee river and the middle murray river near echuca as upper catchment areas were revegetated following the lgm discharge or sediment supply may have declined first in lower altitude catchments like the goulburn and last in the high altitude upper murray catchment creating an asynchronous transition from palaeochannel to modern fluvial activity in subcatchments of the southeast murray drainage basin

sea ice growth and water mass modification in the mertz glacier polynya east antarctica during winter in july september 1999 an extensive oceanographic survey 87 conductivity temperature and depth measuring stations was conducted in the mertz glacier polynya over the adelie depression off the antarctic coast between 145 and 150 e we identify and describe four key water masses in this polynya highly modified circumpolar deep water hmcdw winter water ww ice shelf water isw and high salinity shelf water hssw combining surface velocity data from an acoustic doppler current profiler with three hydrographic sections we found the hmcdw to be flowing westward along the shelf break 0 7 sv the ww and hssw flowing eastwards underneath mertz glacier 2 0 sv and that there was a westward return flow of isw against the continent 1 2 sv using a simple box model for the exchanges of heat and fresh water between the principal water masses we find that the polynya was primarily a latent heat polynya with 95 of the total heat flux caused by sea ice formation this heat flux results from a fresh water equivalent sea ice growth rate of 4 9 7 7 cm d 1 and a mass exchange between hmcdw and ww of 1 45 sv the inferred ocean heat flux is 8 14 w m 2 and compares well with other indirect estimates

climatic records over the past 30 ka from temperate australia a synthesis from the oz intimate workgroup temperate australia sits between the heat engine of the tropics and the cold southern ocean encompassing a range of rainfall regimes and falling under the influence of different climatic drivers despite this heterogeneity broad scale trends in climatic and environmental change are evident over the past 30 ka during the early glacial period 30 22 ka and the last glacial maximum 22 18 ka climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important murray darling basin the temperate region at this time appears to be dominated by expanded sea ice in the southern ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast including tasmania and southwest australian coasts the deglacial period 18 12 ka was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records while there is some evidence for climatic reversals e g the antarctic cold reversal in high resolution marine sediment cores through this period the high spatial density of holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after 12 ka presumably in response to increasing temperature while hydrological records reveal spatially heterogeneous hydro climatic trends patterns after 6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the el nino southern oscillation

effects of regional fast ice and iceberg distributions on the behaviour of the mertz glacier polynya east antarctica an observational account of research carried out in july august 1999 shows that grounded iceberg and related fast ice distributions and periodic break outs of fast ice in winter as well as at other times have an important impact on the size and behaviour of the mertz glacier polynya east antarctica and a smaller polynya to the east analysis of satellite and in situ data shows that a semi constant stream of thick broken out fast ice and other large floes from the east extends westwards from north of the glacier terminus to form a compact barrier to the net west northwesterly export of ice formed in the polynya an annual fast ice promontory to the west further narrows the outlet path as a result of this and high ice production rates the polynya periodically back fills significantly reducing the open water area present intervening flush outs by synoptic storm events clear the polynya region to some extent before it back fills again this cycle continued from mid march until early october in 1999 when a significant change in the regional ice drift occurred a preliminary comparison with data from 1998 indicates that the timing and magnitude of the processes may vary interannually similar morphological features were also observed in 1963 on a declassified photoreconnaissance satellite image

polynya dynamics a review of observations and modeling 1 polynyas are nonlinear shaped openings within the ice cover ranging in size from 10 to 105 km2 polynyas play an important climatic role first winter polynyas tend to warm the atmosphere thus affecting atmospheric mesoscale motions second ocean surface cooling and brine rejection during sea ice growth in polynyas lead to vertical mixing and convection contributing to the transformation of intermediate and deep waters in the global ocean and the maintenance of the oceanic overturning circulation since 1990 there has been an upsurge in polynya observations and theoretical models for polynya formation and their impact on the biogeochemistry of the polar seas this article reviews polynya research carried out in the last 2 decades focusing on presenting a state of the art picture of the physical interactions between polynyas and the atmosphere sea ice ocean system observational and modeling studies the surface heat budget and water mass transformation within these features are addressed

reconstructing palaeoenvironments on desert margins new perspectives from eurasian loess and australian dry lake shorelines abstract desert margins preserve evidence of more extensive arid conditions in the past and represent global hot spots with respect to climate change the balance of scientific evidence now suggests that dryland landscape reactivation did not correspond simply to ice age aridity peaks as previously assumed this paper provides a new perspective on and more nuanced understanding of desert marginal landscapes as palaeoenvironmental archives the two case studies represent ends of a sediment availability spectrum both environments experience substantial spatial and temporal variability in deposition with implications for reconstructing past environments at individual sites recently generated chronostratigraphic data from the dry subhumid dobrogea loess romania are synthesised to provide quantitative insights into the spatial and temporal organisation of loess plateaux loess accumulation peaks during the lgm and mis4 but not at all sites accumulation rates vary substantially between sites comparison of geographical context yields no clear driving mechanism for this variability secondly two transverse lunette dunes in semi arid willandra lakes australia yield comparable chronostratigraphies and distribution of stratigraphic units a first attempt is made to identify changes in wind regime through time on the australian desert margins and suggests that high latitude climate forcing may have acted upon semi arid australia over millennial scales the novel perspectives generated from the new datasets provide unprecedented insights into past climate circulation and land surface processes along desert margins these new perspectives coupled with the new geochronological and quantitative palaeoclimate proxy tools now available represent the next frontier for palaeoenvironmental research on desert margins

fish otolith microchemistry snapshots of lake conditions during early human occupation of lake mungo australia abstract the 18 o strontium calcium and barium calcium values recorded in golden perch otoliths collected from two evaporative lakes modern lake hope and ancient lake mungo have been used to reconstruct changes in water composition and environmental conditions during the life of the fish lake hope was filled by floodwaters in 1989 and 1990 then a period of lake drying was followed by a natural fish death event in 1994 otoliths from these fish have 18 o profiles reflecting the earlier floods and the progressive evaporation of the lake sr ca ratios start to follow the 18 o trend only after evaporation is well advanced probably after the fish became stressed otoliths from a period of early human occupation at lake mungo 14 c age range ca 37 42 cal kbp record a different history most otoliths show a relatively stable 18 o profile throughout the life of each fish with no evidence of significant lake flooding or drying sr ca ratios are similarly stable indicating that over a period of ca 5 ka evaporation and inflow remained in relative balance all the otoliths have high ba ca ratios during the early years of the fish likely a juvenile biological effect in common the mungo otoliths differ in also showing a rise in ba ca ratios in the outermost layers as yet unexplained one mungo otolith 14 c dated at ca 19 3 cal kbp does show evaporation and stress trends in 18 o and sr ca ratios respectively consistent with other evidence that lake mungo was subject to frequent drying at that time

modeling interannual dense shelf water export in the region of the mertz glacier tongue 1992 2007 ocean observations around the australian antarctic basin show the importance of coastal latent heat polynyas near the mertz glacier tongue mgt to the formation of dense shelf water dsw and associated antarctic bottom water aabw here we use a regional ocean ice shelf model to investigate the interannual variability of the export of dsw from the adelie west of the mgt and the mertz east of the mgt depressions from 1992 to 2007 the variability in the model is driven by changes in observed surface heat and salt fluxes the model simulates an annual mean export of dsw through the adelie sill of about 0 070 06 sv from 1992 to 1998 the export of dsw through the adelie mertz sills peaked at 0 14 sv 0 29 sv during july to november during periods of mean to strong polynya activity defined by the surface ocean heat loss dsw formed in the adelie depression can spread into the mertz depression via the cavity under the mgt an additional simulation where ocean ice shelf thermodynamics have been disabled highlights the fact that models without ocean ice shelf interaction processes will significantly overestimate rates of dsw export the melt rates of the mgt are 1 20 4 m yr 1 during periods of average to strong polynya activity and can increase to 3 81 5 m yr during periods of sustained weak polynya activity due to the increased presence of relatively warmer water interacting with the base of the ice shelf the increased melting of the mgt during a weak polynya state can cause further freshening of the dsw and ultimately limits the production of aabw

wintertime heat flux to the underside of east antarctic pack ice in the sea ice zone there is a delicate balance between the heat loss from the surface of the snow covered sea ice and the heat supplied to the underside of the ice by the deep ocean the difference between these two heat fluxes determines the amount of ice growth or melt in global atmospheric models the ocean heat flux is often prescribed and has been shown to be an important parameter in determining how thick sea ice will grow thermodynamically although this ocean heat flux is a critical component in climate models there are relatively few direct measurements in the antarctic sea ice region in this study we use measurements of the temperature gradient through the sea ice and of ice growth during a field experiment to estimate the ocean heat flux in the east antarctic region around 140 e 65 s during august 1995 we find an average ocean heat flux of 13 0 14 5 w m 2 this is more than twice the winter values reported in the western weddell sea under multiyear sea ice but similar to the 19 w m 2 that has been estimated for the entire weddell gyre during august 1995 the air temperature showed large variations ranging from near freezing to 30 c this resulted in the thicker ice floes 50 60 cm alternating between a no growth or melting condition and an active ice growth at the base however it is likely that the thicker 60 cm ridged portions of the floes were continually melting

processes controlling the formation of the mertz drift george vth continental shelf east antarctica evidence from 3 5 khz sub bottom profiling and sediment cores recently discovered sediment drift deposits on the antarctic continental shelf provide access to information on the holocene palaeoceanography of the bottomcurrent regime within deep shelf basins that were previously inaccessible the george vth basin on the east antarctic margin has been identified by oceanographers as an important source of antarctic bottomwater hence the holocene history of bottomcurrent activity here may be relevant to variations in bottom water export the analysis of seismic and sediment core data indicates that the holocene history of sedimentation on the mertz drift occurred in response to a progressively changing bottom current regime the stratigraphic horizons that mark the onset of different phases of deposition are diachronous within the mertz drift rapidly accumulating laminated siliceous mud and diatom ooze smo that comprises the bulk was deposited first on the eastern side of the drift 5000 3500 years bp and later on the lobate southwestern side 3000 and 2000 years bp this spatial variation in timing of rapid smo deposition is attributed to a gradual increase in bottom current speed over the mid to late holocene the deposition of true drift style sedimentary features is restricted to a small area in the southwestern corner of the mertz drift with the remaining parts characterised by drape and fill deposits an estimation of the mass flux of sediment reaching the drift suggests that the modern stronger bottom currents need carry only a very low suspended sediment concentration to explain the measured 10 fold reduction in sediment accumulation rates after 3000 years bp cores fromthe mertz drift and froma perched basin located 60 kmto the east contain the same lithologic units and have the same approximate age thus the palaeoenvironmental interpretations based on the mertz drift can be extrapolated over the entire george vth basin region

palaeohydrology of lowland rivers in the murray darling basin australia abstract this study derives a new function describing the relationship of channel bankfull discharge qbf to channel width in modern rivers of the murray darling basin mdb of southeastern australia and applies this to dated palaeochannels of seven rivers to quantify late quaternary discharge history in this important basin all rivers show high mis3 and mis2 qbf declining in the holocene the qbf of modern mdb rivers is correlated with total catchment precipitation but comparison with palaeochannel qbf estimates shows that while enhanced runoff efficiency is necessary to account for much larger late pleistocene palaeochannels either lower or higher precipitation rates could have prevailed a strong association between relative palaeo qbf enhancement and temperature suggests a temperature mediated mechanism controlling river discharge such as the fraction of precipitation stored as snow and thawing in spring the enhancement of orographic rainfall or co2 feedbacks with vegetation cover significantly enhanced mis3 qbf requires an additional mechanism such as increased rainfall these findings are consistent with others that increased moisture availability was associated with past colder climates although this was not necessarily the result of enhanced precipitation

an anomalous late season change in the regional sea ice regime in the vicinity of the mertz glacier polynya east antarctica 1 this paper examines a major late season shift in atmospheric circulation over the east antarctic sea ice zone that occurred in october 1999 the mean wind direction at 65 s 145 e changed from south southeasterly to west southwesterly resulting in almost a complete reversal of the climatological east wind drift pattern in large scale sea ice advection over the southern ocean sector 135 170 e by comparison with national centers for environmental prediction national center for atmospheric research reanalysis time series from 1980 to 2000 this shift is shown to be unusual in terms of both its persistence and impact although similar though less prolonged patterns occurred in 1984 and 1985 lasting from october 1999 to february 2000 it had a profound impact on sea ice concentration and extent over a vast area by coinciding with the period of maximum ice extent and persisting through to the springtime melt phase it also contributed to the rapid annual meltback of sea ice it also had a large and complex effect on the behavior of the globally important mertz glacier polynya and on the areal extent of thick perennial sea ice to the east while a midlatitude blocking high pattern provided the initial impetus for the shift in 1999 the persistence of west southwesterly winds through february 2000 appears to relate to an unusually persistent southward migration of the antarctic circumpolar trough act in addition to the prolonged 1999 episode a strong seasonal signal is apparent throughout the mean wind speed and direction time series related to the act migration although less persistent than in 1999 this annual shift has implications for the observed dramatic annual meltback of east antarctic sea ice

seasonal and subseasonal climate changes recorded in laminated diatom ooze sediments adelie land east antarctica a 40 m long sediment core covering the 1000 9600 years bp period was retrieved from the dumont d urville trough off adelie land east antarctica during the md 130 images x cado cruise this sedimentary sequence allows the documentation of changes in climate seasonality during the holocene here we show preliminary results of diatom communities lithic grain distribution and titanium content measured on two 30 cm long sequences of thin sections the two sequences originate from two different climate regimes the colder neoglacial and the warmer hypsithermal proxies were measured at microscale resolution on 25 laminations for the neoglacial and 14 laminations for the hypsithermal the two sequences reveal alternating light green and dark green laminae light laminae result from low terrigenous input and high sea ice edge diatom fluxes and are interpreted to represent the spring season dark laminae result from high terrigenous input mixed with a diversified open ocean diatom flora and are interpreted to represent the summer autumn season the two sequences therefore resolve annual couplets composed of one light plus one dark lamina variations in the relative thickness of laminations and annual couplets associated with diatom assemblage changes are observed in each sequence and between the two sequences giving information on interannual to millennial changes in environmental conditions

14c activity and global carbon cycle changes over the past 50 000 years a series of 14c measurements in ocean drilling program cores from the tropical cariaco basin which have been correlated to the annual layer counted chronology for the greenland ice sheet project 2 gisp2 ice core provides a high resolution calibration of the radiocarbon time scale back to 50 000 years before the present independent radiometric dating of events correlated to gisp2 suggests that the calibration is accurate reconstructed 14c activities varied substantially during the last glacial period including sharp peaks synchronous with the laschamp and mono lake geomagnetic field intensity minimal and cosmogenic nuclide peaks in ice cores and marine sediments simulations with a geochemical box model suggest that much of the variability can be explained by geomagnetically modulated changes in 14c production rate together with plausible changes in deep ocean ventilation and the global carbon cycle during glaciation

the distribution and formative processes of latent heat polynyas in east antarctica a study of polynya characteristics in east antarctica was undertaken using ice concentrations derived from special sensor microwave imager data for the period july 1987 august 1994 the areas of polynyas were defined as having an ice concentration 75 the analysis revealed a total of 28 coastal polynyas within the study region the spatial and temporal variability in areal extent was quantified the timing of mean maximum areal extent varied from june to october the bathymetry and wind regime at each polynya site was examined to gauge the relative importance of these parameters in polynya formation and maintenance in 20 locations shallow banks and shoals form grounding zones for icebergs and anchoring sites for fast ice which form barriers to the predominantly westward drift of the pack ice elsewhere north south coastal protrusions or alignments form similar barriers the subsequent removal of newly formed sea ice from the lee of such barriers by katabatic and synoptic winds maintains areas of reduced ice concentration and open water very few coastal polynyas are attributed solely to katabatic outflow the combined influence of bathymetry topography and winds is responsible for the characteristics of the majority of polynyas many were considered to be marginal characterised by occasional periods when the ice concentration falls below 75 an analysis of annual winter totals of areas with ice concentrations 75 shows no trends in total polynya areal extent over the period 1987 94 known locations of emperor penguin aptenodytes forsteri rookeries were also found to be associated with the locations of coastal polynyas

evidence for regionally wet conditions before the lgm in southeast australia osl ages from a large palaeochannel in the lachlan valley abstract optically stimulated luminescence osl techniques have been used to obtain the rstages on late pleistocene channels in the lachlan valley southeastern australia two osl ages fromchannel sand and overlying source bordering dune sand indicate that large sinuous channels withbankfulldischargessixtoeighttimesgreaterthanthepresentriver werefullyestablishedby34kabp this conclusion is consistent with regional lake level and geomorphic evidence of cool pluvialconditions that preceded the last glacial maximum lgm providing new information on a long standing palaeohydrological problem caused by the apparent synchroneity of large river systems andregional aridity copyright 2007 john wiley sons ltd keywords late quaternary palaeochannels palaeohydrology quartz osl luminescence dating the late pleistocene environmental history of southeasternaustralia relies to a large extent on the relict rivers lakes anddune elds of the riverine plain occupied today by the murrayriver and its tributaries the goulburn murrumbidgee lachlanand darling rivers which rise on the southeastern highlands during the terminal pleistocene the plains supported large actively meandering channels with scrolled oodplains sub stantially larger and carrying coarser sediment loads thanthe irregularly sinuous and muddy present day channels thegoulburn and murrumbidgee palaeochannels have been wellstudied and chronologies based on radiocarbon and thermo luminescence tl suggest two periods of large meanderingchannel activity from 35ka to 25ka and 20ka to 13ka bowler 1978 bowler et al 1978 schumm 1968 page et al 1991 1996 page and nanson 1996 however the regionalchronology does not clearly reveal two synchronous periodsofactivity table1 andisbedevilledbydatinguncertainties forexample suspected contamination of some radiocarbon datesby younger organic compounds contained in the groundwater bowler 1978 was con rmed when kotupna sedimentsradiocarbon dated at 16 13k

late quaternary changes in flow regime on the gwydir distributive fluvial system southeastern australia abstract ages for large palaeochannels of the gwydir distributive fluvial system dfs in northern new south wales australia have been determined using single grain optically stimulated luminescence two palaeochannel systems have been found to dominate the here named coocalla 43 34 ka and kamilaroi 19 16 ka which have inferred palaeodischarges 25 100 times the bankfull discharges of nearby channels of the contemporary gwydir system which appears to have been established during the mid holocene this scale differential is very much larger than that reported for other catchments in southeastern australia and reflects both a decline in catchment runoff through the last glacial cycle and the adoption of a distributary pattern sometime after 16 ka actual decline in catchment runoff determined by comparing estimated palaeodischarge with contemporary flows upstream of the dfs where flow is confined to a single channel indicate contemporary discharge to be 0 1 times and 0 25 times that of the coocalla and kamilaroi respectively the chronology presented here shows periods of increased discharge in the gwydir to be more or less coincident with those observed elsewhere in the murray darling basin although no evidence of a gum creek fluvial phase from 35 to 25 ka was found the coocalla and kamilaroi palaeochannel systems broadly conform in age to kerarbury and yanco fluvial phases on the murrumbidgee and murray systems this synchronicity with more southern catchments supports the hypothesis that la nina like conditions were semi permanent for much of the last glacial cycle with moisture derived largely from the western pacific ocean

changes in water properties and flow regime on the continental shelf off the adelie george v land coast east antarctica after glacier tongue calving oceanic changes before and after the relocation of iceberg b9b and calving of the mertz glacier tongue mgt in february 2010 are examined on the continental shelf off the adelie land george v land coast east antarctica summer hydrographic observations including stable oxygen isotope ratio 18o in 2001 2008 and 2011 2015 and results of a numerical model are used along the western flank of the mgt temperature decreased between 2001 and 2015 for most of the water column in the adelie depression 18o generally decreased especially at the mgt draft depths on the northern side west of the mgt temperature salinity and 18o decreased in the intermediate layer east of the mgt in contrast temperature increased between 2001 and 2011 at intermediate depths salinity increased in the intermediate and deep layers and 18o slightly decreased in the deep layer but did not change much around 300 dbar the numerical experiment exhibits a change in ocean circulation revealing an increase in modified circumpolar deep water mcdw inflow in the east and a decrease in the west the contrasting changes in mcdw intrusion are consistent between the observations and numerical model and are indicative of the effect of removal of the ice barriers the contrast is overlain by overall decreases in salinity and 18o which suggests an increase in the continental meltwater fraction of 5 20 and might reveal a wide ranging influence from west antarctica the oxygen isotope ratio is hence effective in monitoring the increase in continental melt over the antarctic shelf

continental shelf drift deposit indicates non steady state antarctic bottom water production in the holocene a late quaternary current lain sediment drift deposit over 30 m in thickness has been discovered on the continental shelf of east antarctica in an 850 m deep glacial trough off george vth land radiocarbon dating indicates that a period of rapid deposition on the drift averaging 290 cm kyr occurred in the mid holocene between about 3000 and 5000 yr before present slower rates of around 10 cm kyr during the past 0 3000 yr and from 5000 to about 13000 yr bp coincides with deposition of bioturbated ice rafted debris ird rich sandy mud under an energetic bottom current regime in contrast the mid holocene 3000 5000 yr bp sediments are fine grained laminated to cross laminated with minimal ird content and are contemporaneous with a period of warmer marine conditions with less sea ice production this pattern suggests that bottom currents were weaker than present day in the mid holocene and that the rate of dense bottom water production was reduced at that time this scenario is consistent with the hypothesis of non steady state rates of antarctic bottom water production through the holocene as recently proposed by broecker and his colleagues

modeling of antarctic sea ice in a general circulation model a dynamic thermodynamic sea ice model is developed and coupled with the melbourne university general circulation model to simulate the seasonal cycle of the antarctic sea ice distribution the model is efficient rapid to compute and useful for a range of climate studies the thermodynamic part of the sea ice model is similar to that developed by parkinson and washington the dynamics contain a simplified ice rheology that resists compression the thermodynamics is based on energy conservation at the top surface of the ice snow the ice water interface and the open water area to determine the ice formation accretion and ablation a lead parameterization is introduced with an effective partitioning scheme for freezing between and under the ice floes the dynamic calculation determines the motion of ice which is forced with the atmospheric wind taking account of ice resistance and rafting the simulated sea ice distribution compares reasonably well with observations the seasonal cycle of ice extent is well simulated in phase as well as in magnitude simulated sea ice thickness and concentration are also in good agreement with observations over most regions and serve to indicate the importance of advection and ocean drift in the determination of the sea ice distribution

of droughts and flooding rains an alluvial loess record from central south australia spanning the last glacial cycle david haberlah peter glasby martin a j williams steven m hill frances williams edward j rhodes victor gostin anthony o flaherty and geraldine e jacobsen

late pleistocene lake level history of lake mungo australia abstract lake mungo is a currently dry lake basin in the semi arid zone of southeastern australia the transverse dune system on the downwind side contains a record of human occupation of international importance it also contains one of the most continuous records of climate change over the last glacial cycle in the australia desert in this paper we provide a framework for the interpretation of lake level history from before the arrival of people 41 ka until after the establishment of the pastoral industry in the area we present 83 optically stimulated luminescence ages from the lake mungo lunette the lake level history is reconstructed from 34 stratigraphic sections along three transects through the lunette the dating reveals considerable lake level fluctuations through time which occur over a depth range of 10 m in the basin at its height probably at multiple times before 20 ka the lake held more than 1 km3 of water and at its final level at 19 ka contained only 0 03 km3 the inception of lake mungo appears to have taken place during the mid pleistocene between 256 and 369 ka during the last glacial cycle lake mungo was almost continuously wetter than present from shortly after 60 ka until 19 ka the upper mungo arumpo and zanci units represent a succession of lake filling and drying events briefly interspersed by soils the final zanci unit does not represent a single high lake phase but an initial lake filling followed by a series of short lived lake level events within a brief period of a few thousand years at the conclusion of this event the lake remained dry until the present day four osl ages from a linear dune upwind of lake mungo indicates regional aeolian activity from 30 ka until present widespread erosion that produces the characteristic topography of the lunette began after the arrival of british pastoralists and traditional aboriginal ways of life overlapped briefly with this erosion the presence of water in lake mungo closely corresponds to periods when regional surface temperature was colder than present during the late pleistocene our new data supports a model that decreased evaporation and increased runoff were primarily responsible for increased availability of surface water in the hydrological cycle

ice sheet record of recent sea ice behavior and polynya variability in the amundsen sea west antarctica investigation of how regional sic is recorded in the ice sheet stratigraphy over the period 2002 2010 we find that the ice sheet chemistry is significantly correlated with sic variability within the as and pine island bay polynyas based on this result we evaluate the use of icecore chemistry as a proxy for interannual polynya variability in this region one of the largest and most persistent polynya areas in antarctica msa concentrations correlate strongly with summer sic within the polynya regions consistent with msa at this site being derived from marine biological productivity during the spring and summer cl concentrations correlate strongly with winter sic within the polynyas as well as some regions outside the polynyas consistent with cl at this site originating primarily from winter sea ice formation spatial correlations were generally insignificant outside of the polynya areas with some notable exceptions ice core glaciochemical records from this dynamic region thus may provide a proxy for reconstructing as and pine island bay polynya variability prior to the satellite era

modeling sea ice production and dense shelf water formation in coastal polynyas around east antarctica 1 using an ice ocean coupled model with fine horizontal resolution around east antarctica sea ice production and dense shelf water dsw formation in coastal polynyas are investigated the model reproduces well the locations of coastal polynyas and the high sea ice production there dsw is formed over the continental shelves under a number of coastal polynyas a threshold density beyond which net production of dsw takes place is largely different among coastal polynyas the densest and most vigorous dsw formation occurs in the cape darnley and mertz ninnis glacier polynyas followed by somewhat less but still significant dsw formation in the prydz barrier and vincennes polynyas assuming mixing of the dsw outflowing across the shelf break with typical modified circumpolar deep water over the continental slope the maximum possible formation rate of antarctic bottom water aabw is estimated to be 7 58 sv around east antarctica between 60 e and 150 e with the cape darnley and mertz ninnis glacier polynyas exhibiting the most active formation rates of 2 13 and 1 97 sv respectively from a series of numerical experiments it is found that the treatment of coastline and grounded icebergs has a large impact on both sea ice production and formation of dsw and aabw

summer plankton production and nutrient consumption patterns in the mertz glacier region of east antarctica abstract we report on a biological and nutrient survey conducted off the eastern adelie and george v coasts of east antarctica in late december 2000 and january 2001 the region was dominated by the mertz glacier tongue mgt and its associated polynya that controlled the amount of open water through the season and influenced stratification near forming and melting ice as in other regions of the southern ocean large concentrations of nitrate phosphate and silicic acid were found chlorophyll levels varied from 0 3 mg m 3 in pack ice and slope regions to greater than 10 mg m 3 in a phaeocystis bloom encountered among grounded ice northeast of the mgt net utilization rates of nutrients were derived from the deficit between measured concentrations and estimated winter values nitrate n n and silicic acid utilization rates ranged from 2 to 12 and 14 to 30 mmol m 2 d 1 respectively and were greatest in commonwealth bay the ratio of nitrate to phosphate utilization was low 10 lower silicic acid to n n ratios were found in regions with substantial populations of phaeocystis sp in the eastern grounded ice region however there was significant variation in the silicic acid to n n utilization that may be induced by mixed layer iron levels that varied from

an extended last glacial maximum in subtropical australia a continuous record encompassing the termination of the last glacial cycle defined here as ca 30 18 cal kyr bp has been developed using multiple proxies viz clastic sediment flux grain size moisture content pollen and charcoal archived in lake sediments from tortoise lagoon north stradbroke island australia the record indicates an extended last glacial maximum with an onset at ca 30 kyr bp the presence of rainforest and arboreal taxa for the 30 18 kyr bp period indicate a positive moisture balance while the presence of the now regionally extinct asteraceae tubuliflorae and tubulifloridites pleistocenicus indicate relatively cool temperatures total clastic sediment flux and the vegetation assemblage suggest that at least in subtropical australia the last glacial maximum was characterized by two peaks in aridity at ca 29 26 kyr bp and 24 5 20 kyr bp

a high resolution late quaternary depositional history and chronology for the southern portion of the lake mungo lunette semi arid australia abstract the willandra lakes region sits on the southern margin of australia s arid core and is one of the oldest localities on the continent known to have been occupied by australia s first people the archaeological traces that accumulated in the lake mungo lunette paint a picture of changing land use over the past 50 thousand years ka and some of these are likely to have been responses to changes in palaeoenvironmental conditions this study set out to determine the finest temporal resolution that can be used to study the depositional and palaeoenvironmental history of the lake mungo lunette the investigation focused on the depositional history documented within stratigraphy exposed in an eroding gully in the southern part of the lunette gully 10 a stratigraphic framework was developed using sedimentological and soil micromorphological analysis this framework was then fixed in time by 56 single grain optically stimulated luminescence osl age estimates these data sets were then combined into a bayesian model that indicated three depositional phases 100 ka lu1 65 33 ka lu2 lu3 and from 30 to 16 ka lu4 lu9 with the late pleistocene and holocene samples lu10 11 not being modelled furthermore the redating of thirteen lower and upper mungo osl samples from bowler et al 2003 s study of the southern tip of the lunette yielded younger age estimates for twelve of these bringing them into line with previously published independent age control as well as the ages presented in this study this study provides an approach for future efforts to establish consistency in age estimation and palaeoenvironmental interpretation along the length of the lunette

a 100 ka record of fluvial activity in the fitzroy river basin tropical northeastern australia this study reports the nature and timing of quaternary fluvial activity in the fitzroy river basin which drains a diverse 143 000 km 2 area in northeastern queensland before discharging into the

on the circulation and water masses over the antarctic continental slope and rise between 80 and 150 e abstract the circulation and water masses in the region between 80 and 150 e and from the antarctic continental shelf to the southern boundary of the antarctic circumpolar current acc 62 s are described from hydrographic and surface drifter data taken as part of the multi disciplinary experiment baseline research oceanography krill and the environment broke two types of bottom water are identified adelie land bottom water formed locally between 140 and 150 e and ross sea bottom water ross sea bottom water is found only at 150 e whereas adelie land bottom water is found throughout the survey region the bottom water mass properties become progressively warmer and saltier to the west suggesting a westward flow all of the eight meridional ctd sections show an antarctic slope front of varying strength and position with respect to the shelf break in the water formation areas between 140 and 150 e and 104 e the antarctic slope front is more v shaped while elsewhere it is one sided the shape of the slope front and the presence or absence of water formation there are consistent with other meridional sections in the weddel sea and simple theories of bottom water formation gill 1973 deep sea research 20 111 140 whitworth et al 1998 in jacobs and weiss eds ocean ice and atmosphere interactions at the antartic continental margin antarctic research series american geophysical union washington pp 1 27 adcp surface velocities and buoy drift tracks show a strong westward flow over the shelf and slope regions in the region 90 100 e there is a strong eastward flow of the waters just south of the southern boundary of the acc suggesting a recirculation of the westward slope current and the presence of a weak cyclonic gyre using the adcp velocities as a reference for the ctd data the average westward transport in this region is 29 4 14 7 sv

lacustrine fluvial interactions in australia s riverine plains climatic forcing of fluvial systems has been a pre occupation of geomorphological studies in australia since the 1940s in the riverine plain southeastern australia the stable tectonic setting and absence of glaciation have combined to produce sediment loads that are amongst the lowest in the world surficial sediments and landforms exceed 140 000 yr in age and geomorphological change recorded in the fluvial fluvio lacustrine and aeolian features have provided a well studied record of quaternary environmental change over the last glacial cycle the region includes the willandra lakes whose distinctive lunette lakes preserve a history of water level variations and ecological change that is the cornerstone of australian quaternary chronostratigraphy the lunette sediments also contain an ancient record of human occupation that includes the earliest human fossils yet found on the australian continent to date the lake level and palaeochannel records in the lachlan willandra system have not been fully integrated making it difficult to establish the regional significance of hydrological change here we compare the willandra lakes environmental record with the morphology and location of fluvial systems in the lower lachlan an ancient channel belt of the lachlan willandra creek acted as the main feeder channel to willandra lakes before channel avulsion caused the lakes to dry out in the late pleistocene electromagnetic surveys geomorphological and sedimentary evidence are used to reconstruct the evolution of the first new channel belt following the avulsion single grain optical dating of floodplain sediments indicates that sedimentation in the new middle billabong palaeochannel had commenced before 18 4 1 1 ka a second avulsion shifted its upper reaches to the location of the present lachlan river by 16 2 0 9 ka the timing of these events is consistent with palaeohydrological records reconstructed from willandra lakes and with the record of palaeochannels on the lachlan river upstream willandra lakes shows high inflows during the last glacial maximum 22 ka but their subsequent drying between 20 5 ka and 19 ka was caused by river avulsion rather than regional aridity this case study highlights the benefits of combining fluvial with lacustrine archives to build complementary records of hydrological change in lowland riverine plains

a multi method approach to dating the burial and skeleton of kiacatoo man new south wales australia kiacatoo man a large rugged aboriginal adult buried in the lachlan riverine plains of southeastern australia was discovered in 2011 laser ablation uranium series analysis on bone yielded a minimum age for the burial of 27 4 0 4 ka 2 single grain optically stimulated luminescence ages on quartz sediment in which the grave had been dug gave a weighted mean age of 26 4 1 5 ka 1 luminescence samples from the grave infill and from sediment beneath the grave exhibit overdispersed dose distributions consistent with bioturbation or other disturbance which has obscured the burial signal the overlap between the minimum u series and maximum luminescence ages places the burial between 27 0 and 29 4 ka 2 luminescence ages obtained from the channel belt of between 28 2 and 25 3 ka indicate that fluvial sedimentation was occurring before the last glacial maximum which is consistent with the broader geomorphic setting together these results are internally and regionally consistent and indicate that kiacatoo man was one of the more ancient individuals so far identified in australia his remains are important to our understanding of patterns of biological variation and other processes that have shaped people in the murray darling basin through time

flood channel morphology of a quiet river the lachlan downstream from cowra southeastern australia abstract detailed geomorphic mapping and sediment analyses of floodplain features were undertaken on a 30 km reach of the lachlan river in southeastern australia the reach is located in the transitional zone between the southern great dividing range and extensive alluvial plains to the west the channel resembles other fine grained low energy alluvial channels it is muddy narrow and deep and meanders irregularly it contains fine grained accreting bench deposits and in places is influenced by inherited fluvial forms both of which indicate long term channel stability by contrast the floodplain exhibits features that have been attributed elsewhere to catastrophic flood flows including elliptical scour scars swirl pits cobble and gravel deposits large chutes and chute bars zones of floodplain stripping flood levees and multiple flood channels sorting and texture of floodplain sediments generally increases with height above the bed although deposits are variable and poorly sorted indications of recent fluvial activity at several levels above the bed are confirmed by aerial photographs dating from 1954 although changes to the channel position have been small the alluvial facies model displays a compound floodplain in which a stable low energy channel is inset within a high energy flood dominated floodplain this interpretation is consistent with streamflow and documentary evidence of recurrent large floods since 1839 which have a return period of

spatial mapping of the b value at mount etna italy using earthquake data recorded from 1999 to 2005 1 the spatial pattern of the b value of the frequency magnitude relation has been analyzed using gridding techniques beneath mount etna italy a regional data set of 2900 events with md duration magnitude 1 5 up to 15 km depth occurring between august 1999 and december 2005 has been used two regions with an abnormally high b value have been found one centered beneath the southern part of the valle del bove above the 6 km below sea level bsl deep basement and the other beneath the summit region 2 km bsl east of the central craters we can infer that these high b value anomalies are regions of increased crack density and or high pore pressure related to the presence of nearby magma storage this interpretation is supported by all the available geophysical evidence such as tomographic studies and geodetic deformation measurements the data set has also been subdivided into five periods corresponding to different phases of volcanic activity 2001 preeruption 2001 eruptive 2002 2003 preeruption 2002 2003 eruptive and 2002 2003 posteruption the minimum magnitude of completeness mc and the b value were computed for each period a volume of anomalously high b values can be observed in each of these periods except for the 2002 2003 preeruption interval this approach has allowed the detection of the transient presence of magmatic intrusions during the various periods evaluated

stratigraphic architecture resulting from late quaternary evolution of the riverine plain south eastern australia the riverine plain of south eastern australia is the result of prolonged cenozoic fluvial activity single thread anabranching and distributary channels and floodplains and associated aeolian dunes characterize the uppermost sequences based on detailed interpretations of late quaternary fluvial sedimentation and surficial stratigraphy for this 77 000 km2 basin earlier prior stream and ancestral stream models of fluvial deposition deduced from limited stratigraphic and chronological evidence are replaced with aggradational palaeochannel and migrational palaeochannel models thermoluminescence dating reveals four distinct phases of palaeochannel activity between 105 and 12 ka the first coleambally phase late in oxygen isotope stage 5 the second kerarbury phase in stage 3 the third gum creek phase before and the fourth yanco phase after the last glacial maximum lgm in stage 2 the first three of these phases were characterized by mixed load laterally migrating sinuous palaeochannels with occasional transitions to a straighter bedload dominated mode and vice versa the first two phases concluded with a bedload dominated episode resulting in aggradational palaeochannels on the surface of the plain and the third phase prior to the lgm did also in its downstream reaches the phase following the lgm was characterized entirely by large mixed load sinuous migrational palaeochannels these exhibited no terminating bedload episode because the onset of holocene climates reduced the size of the flood peaks greatly diminished the supply of bedload from the upper catchments and resulted in streams evolving to their present highly sinuous suspended load form the result is a complex stratigraphic architecture consisting of vertically and laterally accreted units extending over hundreds of kilometres in the form of channel sand stringers sand sheets and derivative aeolian dunes partially or wholly encased in overbank fines

episodic fluvial activity of inland rivers in southeastern australia palaeochannel systems and terraces of the lachlan river inland rivers in southeastern australia preserve a long record of surface palaeochannels accompanied by alluvial terraces that reflect changes in water and sediment discharges from the southeastern highlands through much of the last glacial cycle a compilation of ages on rivers of the southern murray darling basin together with new dates from the lachlan river suggest that the fluvial response to climate change has been regionally consistent and responsive to climate change on timescales 10 ka for much of the last glacial cycle inland rivers were mixed load sinuous single and anabranching channels that carried bankfull discharges of between 3 and 11 times present day rivers incision of the upper alluvial plains and valleys occurred in the lead up to the coldest part of the last glacial cycle this was followed at 34 ka by the synchronous development of large meandering channels that may have been associated with lower evapotranspiration from alpine highland catchments accompanied by higher precipitation smaller channels and declining lateral channel sedimentation suggests arid climates during the last glacial maximum and late glacial period with seasonally large actively migrating channels being maintained in rivers dominated by snowmelt runoff from the australian alps during the holocene sensitivity to recorded changes in precipitation amounts and variability differed between catchments with some rivers constructing larger or more actively migrating channels in the early to mid holocene

a shifting river of sand the profound response of australia s warrego river to holocene hydroclimatic change abstract in dryland river catchments palaeochannels provide some of the key records for understanding the changes in river character and behaviour that can occur in response to different extrinsic and intrinsic controls here we combine modern hydroclimatic datasets satellite imagery field surveys and optically stimulated luminescence osl dating of palaeochannels to investigate the response of the 850 km long warrego river located in central eastern australia to holocene hydroclimatic change the modern warrego is an intermittent to ephemeral low energy river unit stream power 4 w m 2 and is characterised by low sinuosity straight narrow

last glacial maximum and last glacial interglacial transition pollen record from northern nsw australia evidence for a humid late last glacial maximum and dry deglaciation in parts of eastern australia this paper presents the results of a palynological investigation into the late last glacial maximum lgm and last deglaciation ca 20 000 9000 cal a bp from little llangothlin lagoon in the sub tropics of eastern australia the lagoon held permanent water during the late lgm and early deglaciation but was intermittently dry during the late deglaciation during the late lgm local vegetation was dominated by a sub alpine herbfield but the significant presence of rainforest taxa in the pollen record indicates the survival of rainforest rainforest margin or wet sclerophyll communities close to the site by ca 17 000 cal a bp open eucalyptus forest replaced the alpine herbfield vegetation indicating that warming had commenced rainforest taxa disappeared at this time but re appeared at the end of the deglaciation the lgm conditions are consistent with a dominant circulation system whereby persistent high pressure over eastern australia brings onshore easterlies to this region and maintains humid conditions along the east coast and highlands of the great dividing range this is similar to modern winter circulation but the persistence of rainforest and wet sclerophyll taxa suggests an increase in easterly flow over modern conditions during the lgm

formation and export of dense shelf water from the adelie depression east antarctica 1 coastal polynyas in the adelie depression are an important source of antarctic bottom water to the australian antarctic basin we present time series april 1998 to may 1999 and august 1999 to february 2000 of data from temperature salinity sensors in both the adelie depression and the known outflow region of the adelie sill to describe the annual cycle of shelf water densities from april through september salinification beneath the polynya produces dense shelf waters during september october shelf water densities in the depression peak at 27 94 kg m 3 and the cooling and freshening signature of ice shelf water is observed north of buchanan bay in november december shelf water densities decrease as intrusions of warm and relatively fresh modified circumpolar deep water enter east of the adelie sill from january march the surface layer is conditioned by the cooling of the atmosphere which overturns the upper water column at the adelie sill observed daily mean currents were approximately 10 cm s 1 with intense instantaneous currents greater than 50 cm s 1 at the sill depth using an idealized outflow region with a rectangular cross sectional area 6 106 m2 we present the first estimates of shelf water export by potential density class assuming shelf water with a minimum density of 27 88 kg m 3 has sufficient negative buoyancy for downslope mixing and a fourfold volume increase 1 3 mixing ratio from entrainment the dense shelf water export of 0 1 0 5 sv results in an annual average production of bottom water in this region of between 0 4 and 2 0 sv the wide range in bottom water estimate results from data limitations and a narrowing of this range requires further mooring observations

community structure and benthic habitats across the george v shelf east antarctica trends through space and time physical and biological characteristics of benthic communities are analysed from underwater video footage collected across the george v shelf during the 2007 2008 ceamarc voyage benthic habitats are strongly structured by physical processes operating over a range of temporal and spatial scales iceberg scouring recurs over timescales of years to centuries along shallower parts of the shelf creating communities in various stages of maturity and recolonisation upwelling of modified circumpolar deep water mcdw onto the outer shelf and cross shelf flow of high salinity shelf water hssw create spatial contrasts in nutrient and sediment supply which are largely reflected in the distribution of deposit and filter feeding communities long term cycles in the advance and retreat of icesheets over millennial scales and subsequent focussing of sediments in troughs such as the mertz drift create patches of consolidated and soft sediments which also provide distinct habitats for colonisation by different biota these physical processes of iceberg scouring current regimes and depositional environments in addition to water depth are important factors in the structure of benthic communities across the george v shelf the modern shelf communities mapped in this study largely represent colonisation over the past 8000 12 000 years following retreat of the icesheet and glaciers at the end of the last glaciation recolonisation on this shelf may have occurred from two sources deep sea environments and possible shelf refugia on the mertz and adelie banks however any open shelf area would have been subject to intense iceberg scouring understanding the timescales over which shelf communities have evolved and the physical factors which shape them will allow better prediction of the distribution of antarctic shelf communities and their vulnerability to change this knowledge can aid better management regimes for the antarctic margin

depositional history and archaeology of the central lake mungo lunette willandra lakes southeast australia abstract lake mungo presently a dry lake in the semi arid zone of southeastern australia preserves a unique record of human settlement and past environmental change within the transverse lunette that built up on its downwind margin the lunette is 30 km long and the variable morphology along its length suggests spatial variability in deposition over time consequently this presents differential potential for the preservation of past activity traces of different ages along the lunette earlier work at lake mungo focused primarily on the southern section of the lunette where two ritual burials of considerable antiquity were found here we describe the depositional history of the central section of the lake mungo lunette together with the first single grain optically stimulated luminescence osl chronology of the full stratigraphic sequence and of three hearths we thereby lay the foundation for systematic investigation of the distribution of archaeological traces through the sedimentary record the older depositional units lower and upper mungo were deposited ca 50 40 ka and 34 ka respectively and are substantially thinner in the central section of the lunette compared with the south by contrast the overlying unit of interbedded sands and clayey sands arumpo zanci units deposited ca 25 14 ka is markedly thicker and dominates the stratigraphic sequence in the central portion of the lunette although the sequence broadly reflects previous models of the lunette s depositional history and changing hydrological conditions our results indicate spatially variable deposition of sediments possibly as a result of changes in prevailing wind regimes archaeological traces are exposed in all stratigraphic units deposited after ca 50 ka including sediments deposited after the final lake drying ca 15 ka indicating human occupation of the area under a range of palaeoenvironmental conditions dating and stratigraphical examination of individual hearth features demonstrates that even within individual stratigraphic units human occupation persisted under variable conditions mid holocene occupation of the area following the final lake retreat took place during a period of relatively humid climate

chronology of murrumbidgee river palaeochannels on the riverine plain southeastern australia four major periods of palaeochannel activity have been identified on the murrumbidgee sector of the riverine plain of southeastern australia on the basis of stratigraphic information the channels reveal a picture of changing flow conditions during the last full glacial cycle the ages of the periods were determined from nearly 40 thermoluminescence dates on surficial fluvial and aeolian sediments these are named the coleambally phase which occurred from 105 to 80 ka the mid to latter part of oxygen isotope stage 5 the kerarbury phase from 55 to 35 ka stage 3 the gum creek phase from 35 to 25 ka late stage 3 to early stage 2 and the yanco phase from 20 to 13 ka late stage 2 the present flow regime was established by about 12 ka stage 1 the first two phases correlate with episodes of enhanced fluvial activity in northern and central australia and with reduced dust activity globally the phases in stage 2 appear to be associated with seasonal snow melt and increased peak flows in periods flanking the last glacial maximum source bordering aeolian dunes associated with the coleambally kerarbury and yanco phases were found however the tl dates show that some have undergone aeolian reworking thermoluminescence dating and fluvial stratigraphy have revealed a detailed picture of late quaternary climate and flow regime changes that has the potential to extend to identified deposits stratigraphically older than those described here

a 40 000 year vegetation history and climatic interpretations of burraga swamp barrington tops new south wales abstract burraga swamp a small basin surrounded by cool temperate rainforest at 985 m in the central new south wales highlands has provided a record of 40 000 years from 40 000 30 000 years bp the site was a lake with a very slow rate of deposition of fine grained sediments and flourishing aquatic swamp vegetation the dryland vegetation was an open or sparsely treed grassland herbfield from 30 000 21 000 years bp the dryland vegetation remained much the same but the aquatic vegetation disappeared from 21 000 17 500 years bp sandy sediments were deposited at an accelerated rate culminating in a layer of gravelly sand possibly the result of periglacial activity only one band of clay in this section contained sufficient pollen to study indicating treeless vegetation after 17 000 years bp the rate of sediment accumulation slowed or ceased and after 15 000 years some mesic elements started to return at 6500 years bp peat started forming and cool temperate rainforest was fully developed remaining on the site to the present this site extends the record of treeless condition at the last glacial maximum to more northerly localities than previously known