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

geomorphic evidence for northeastward expansion of the eastern qilian shan northeastern tibetan plateau abstract the eastern qilian shan is a tectonically active region consisting of a series of faults with bounded intermountain basins and is located within the transition zone between the mainland tibetan plateau and the alax block active deformation affecting the topography in this region can be quantified based on geomorphic indices therefore we applied the geomorphic indices hypsometry and stream power incision model to evaluate the tectonic deformation pattern of the eastern qilian shan hypsometric curves and s a plots of the selected seven rivers were determined hi values of every single sub basins were also calculated the results show that the local topographic evolution of the eastern qilian shan is in pre steady state and will soon reach its equilibrium state according to the analysis of regional climate condition e g rainfall and glaciers distribution and fault characteristics it is suggested that abundant glacial snowmelt water sustains fluvial incision and tectonic deformation from sustained northeastward expansion of the tibetan plateau is the main reason for the landscape growth combining the research of the deep electric structure beneath the gulang boundary zone we claimed that the eastern qilian shan even the northeastern tibet has been growing and expanding northeastward since the middle miocene and its leading edge now is the hexibao sidaoshan fault on the premise of synthetically considering the western and middle parts of the qilian shan it is suggested that the hexibao sidaoshan fault area will rise into a mountain in 1 2 ma

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

landslide erosion coupled to tectonics and river incision the steep topography of mountain landscapes arises from interactions between tectonic rock uplift valley incision and landslide erosion on hillslopes an analysis of more than 15 000 landslides in the eastern himalaya mapped from satellite images shows that steep uplands primarily respond to uplift and river incision by increases in landslide erosion rates rather than by steepened hillslope angles

the application of electron microscopy and microanalysis in conjunction with organic petrology to further the understanding of organic mineral association examples from mount isa and mcarthur basins australia organic petrology supported by electron microscopical and micro analytical techniques was applied to organic matter in proterozoic sediments to better understand hydrothermal processes responsible for ore grade mineralisation it was shown that organic maturation was not only closely linked to the geological history of the sediments but also highlighted heat transfer by convection as differentiated from conduction solely through sediment burial and step wise subsidence water rock ratios effect organic maturation in hydrothermal systems and erratic reflectance profiles are indicators of convective heat transfer identification and characterisation of organic materials in terms of source rock and migrated hydrocarbons was shown to be a powerful tool in reconstructing the thermal history of sediments identifying hydrothermal episodes fluid pathways and heat source in the northern australian proterozoic basins higher reflectance of organic matter towards the central parts of the mount isa basin and some of the most northerly parts point to proximity to higher heat flow at times in contrast to relatively low temperatures prevailing in the western parts of the basin next to the murphy inlier a close correlation shown between peak organic reflectance values and super sequence boundaries farther highlighted the valuable information to be gained from organic petrology by allowing the separation of processes responsible for metal dissolution and transportation from those inducing precipitation c 2001 elsevier science b v all rights reserved

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

hydrothermal maturation of indigenous organic matter at the alligator ridge gold deposits nevada the organic matter of the devonian mississippian pilot shale which hosts the disseminated gold mineralization at alligator ridge nevada has been investigated in an attempt to determine its source and maturation processes and to find an alteration parameter which reflects precious metal distribution more accurately than mineralogical alteration patterns the alligator ridge deposits are similar to other disseminated gold deposits in the great basin of the western united states visible alteration features consisting of quartz replacement of carbonates and oxidation of sulfides and organic matter do not provide significantly useful guides for exploration in this study the type abundance and maturity of organic matter in the pilot shale were determined using techniques standard to petroleum exploration the type and abundance of organic matter in background and mineralized samples are similar transmitted light examination of kerogen concentrates shows that most of the organic matter consists of fine amorphous algal aggregates with a minor amount of vitrinite this corresponds with type i or ii organic matter of tissot and welte 1978 which is derived from a marine source total organic carbon makes up 1 to 3 percent of most carbonaceous rocks at alligator ridge no evidence was found for hydrothermal introduction or remobilization of organic matter the maturity of organic matter as determined by pyrolysis and vitrinite reflectance is considerably higher in mineralized samples than in samples unaffected by the processes of mineralization hydrogen index values for mineralized samples are generally 40 h c approximately 0 5 compared with a background of 230 to 315 h c approximately 1 changes in vitrinite reflectance show a similar but less dramatic change mineralized samples have reflectance values of 1 to 1 3 percent background reflectance is 0 4 to 0 5 percent all reflectance values however are anomalously low due to the extremely small grain size of the vitrinite and therefore cannot be used to determine paleotemperatures spatially hydrogen index contours increase concentrically away from gold mineralization except near the lower pilot shale contact here hydrogen index isopleths are nearly concordant and parallel other alteration features the spatial pattern indicates that hydrothermal flow was dominantly along this contact and away from mineralization this study shows that the organic matter in the pilot shale is of a marine sedimentary origin the total organic carbon of mineralized and background material is similar indicating that the organic matter was not added to the pilot shale hydrothermally however hydrothermal activity has increased the organic matter maturity suggesting that maturation studies can be useful to exploration programs

foraminiferal coloration index as a guide to hydrothermal gradients around the porgera intrusive complex papua new guinea the porgera intrusive complex and gold deposit is hosted in friable black mudstones of cretaceous age in the deformed northern part of the papuan basin papua new guinea hydrothermal fluids associated with the pliocene intrusions created thermal gradients in the surrounding sedimentary rocks these gradients were partitioned by preexisting faults in the sedimentary rocks creating cells of fluid circulation assemblages of agglutinated foraminifera reported from north america have shown color gradients which are interpreted as being related to the thermal maturation of sedimentary rocks down drill holes this paper presents the first known application of color changes in foraminifera marine protistan microfossils to hydrothermal mineral exploration the foraminiferal assemblages of the bathyal mudstones from the porgera region contain abundant agglutinated foraminifera color changes recognized in the agglutinated foraminifera were used to map the thermal maturation of sedimentary rocks in the porgera area palynological fluorescence used in petroleum exploration to determine thermal maturation could not be used owing to the over maturation of the organicmaterials throughout the area surrounding the porgera intrusive complex the agglutinated foraminifera showed a gradation in color from white to dark gray in surface samples taken throughout the porgera area mapping of the foraminifera colors using a geographic information system gis illustrated the thermal maturation of the sedimentary rocks around the intrusive complex owing to conductive heating in addition the mapping showed patterns consistent with convective heating caused by hydrothermal fluid circulation the foraminiferal coloration showed pairing of hot and cold areas across major structures interpreted to be associated with the upflow hot and recharge cold of fluids from the surrounding host sedimentary rocks illite crystallinity and vitrinite reflectance analyses conducted on a transect of samples from across the porgera intrusive complex supported the proposed hydrothermal fluid circulation model interpreted from the foraminiferal colors paleotemperatures associated with the foraminiferal coloration index from the porgera region range from 205 to 415 c and are anomalously high in comparison to other parts of the papuan fold and thrust belt the foraminiferal coloration index fci is a guide to the thermal maturation of sedimentary rocks and provides a useful and low cost exploration tool for locating and evaluating the size of buried intrusive systems in late palaeozoic to cenozoic marine shales it is an invaluable tool for determining the size and partitioning of a hydrothermal cell associated with hydrothermal epithermal mineral deposits the fci method is also useful on a regional scale in areas where sandstones shales or limestones blanket aero magnetic and resistivity data the technique is used currently to identify drilling targets for the exploration of the porgera deposit

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

experimental landform development by rainfall erosion with uplift at various rates abstract four runs 1 2 3 and 4 of physical analog model experiments in which a square ca 60 60 cm column of a mixture of fine sand and kaolinite is slowly raised at different rates ca 5 1 1 3 0 5 0 2 mm h respectively under artificial rainfall of about 38 mm h were conducted to observe how experimental landforms develop in relation to these uplift rates as a square mound gradually emerges from ground level fluvial erosion starts at the mound edges and develops into valley systems this process of fluvial erosion expressed in a linear relationship between relief maximum height minimum height and mean cell slope mean value of the highest slope gradient in a 1 cm 1 cm grid cell dominates until relief reaches about 60 mm around the time when slope failures slumps start to dominate if fluvial erosion dominates throughout the run relief stays below 60 mm the uplift rate is considered to be below the lower threshold and landform development is in the characteristic relief phase in all four runs relief increases above 60 mm and slumps become significant as hills grow indicating that uplift rates in this series are above the lower threshold in run 1 the uplift at a high rate overwhelmed erosion and a massive mountain like topography formed despite the occurrence of large slumps the uplift rate in run 1 is thus above the upper threshold and landform development is in the mountain building phase the mountain is likely to collapse when it grows higher than the limit of mountain growth determined by factors other than uplift rates in runs 2 3 and 4 after valley systems develop over the surface hills grow with the occurrence of slumps and channel profiles seem to become stable at gradients corresponding to the uplift rates as slopes grow steeper than a certain critical gradient which is possibly the angle of repose of dry mound forming material they become vulnerable to slumps however slopes of material containing water and clay can grow steeper than this gradient in the absence of triggering events the frequency distribution of cell slopes becomes bimodal indicating the dominance of two types of slopes divided by the critical gradient one below and another above the former represents surfaces formed mainly by fluvial processes and the latter surfaces formed by and or waiting for slumps slumps reduce relief but average height zmean does not fall unless sediments produced by slumps are carried away by fluvial processes the combination of slope failure fluvial processes and uplift eventually works to keep zmean stable around a certain height depending on uplift rates while relief repeats decrease and increase the experimental landforms in runs 2 3 and 4 seem to have achieved a certain steady state with uplift and erosion the landform development in these runs is considered to be in the steady state phase with uplift rates between the lower and upper thresholds these observations and interpretations are surprisingly consistent with studies on real landforms and can be of value in interpreting their development

hydrocarbon and ore bearing basinal fluids a possible link between gold mineralization and hydrocarbon accumulation in the youjiang basin south china the youjiang basin which flanks the southwest edge of the yangtze craton in south china contains many carlin type gold deposits and abundant paleo oil reservoirs the gold deposits and paleo oil reservoirs are restricted to the same tectonic units commonly at the basinal margins and within the intrabasinal isolated platforms and or bioherms the gold deposits are hosted by permian to triassic carbonate and siliciclastic rocks that typically contain high contents of organic carbon paragenetic relationships indicate that most of the deposits exhibit an early stage of barren quartz pyrite stage i a main stage of auriferous quartz arsenian pyrite arsenopyrite marcasite stage ii and a late stage of quartz calcite realgar orpiment native arsenic stibnite cinnabar dolomite stage iii bitumen in the gold deposits is commonly present as a migrated hydrocarbon product in mineralized host rocks particularly close to high grade ores but is absent in barren sedimentary rocks bitumen dispersed in the mineralized rocks is closely associated and or intergrown with the main stage jasperoidal quartz arsenian pyrite and arsenopyrite bitumen occurring in hydrothermal veins and veinlets is paragenetically associated with stages ii and iii mineral assemblages these observations suggest an intimate relationship between bitumen precipitation and gold mineralization in the paleo petroleum reservoirs that typically occur in permian reef limestones bitumen is most commonly observed in open spaces either alone or associated with calcite where bitumen occurs with calcite it is typically concentrated along pore vein centers as well as along the wall of pores and fractures indicating approximately coeval precipitation in the gold deposits aqueous fluid inclusions are dominant in the early stage barren quartz veins stage i with a homogenization temperature range typically of 230 c to 270 c and a salinity range of 2 6 to 7 2 wt nacl eq fluid inclusions in the main and late stage quartz and calcite are dominated by aqueous inclusions as well as hydrocarbon and co2 rich inclusions the presence of abundant hydrocarbon fluid inclusions in the gold deposits provides evidence that at least during main periods of the hydrothermal activity responsible for gold mineralization the ore fluids consisted of an aqueous solution and an immiscible hydrocarbon phase aqueous inclusions in the main stage quartz associated with gold mineralization stage ii typically have a homogenization temperature range of 200 230 c and a modal salinity around 5 3 wt nacl eq homogenization temperatures and salinities of aqueous inclusions in the late stage drusy quartz and calcite stage iii typically range from 120 c to 160 c and from 2 0 to 5 6 wt nacl eq respectively in the paleo oil reservoirs aqueous fluid inclusions with an average homogenization temperature of 80 c are dominant in early diagenetic calcite fluid inclusions in late diagenetic pore and fissure filling calcite associated with bitumen are dominated by liquid c2h6 vapor ch4 ch4 h2o and aqueous inclusions with a typical homogenization temperature range of 90 c to 180 c and a salinity range of 2 8 wt nacl eq it is suggested that the hydrocarbons may have been trapped at relatively low temperatures while the formation of gold deposits could have occurred under a wider and higher range of temperatures the timing of gold mineralization in the youjiang basin is still in dispute and a wide range of ages has been reported for individual deposits among the limited isotopic data the rb sr date of 206 12 ma for au bearing hydrothermal sericite at jinya as well as the re os date of 193 13 ma on auriferous arsenian pyrite and 40ar 39ar date of 194 6 2 ma on vein filling sericite at lannigou may provide the most reliable age constraints on gold mineralization this age range is comparable with the estimated petroleum charging age range of 238 185 ma and the sm nd date of 182 21 ma for the pore and fissure filling calcite associated with bitumen at the shitouzhai paleo oil reservoir corresponding to the late indosinian to early yanshanian orogenies in south china the close association of carlin type gold deposits and paleo oil reservoirs the paragenetic coexistence of bitumens with ore stage minerals the presence of abundant hydrocarbons in the ore fluids and the temporal coincidence of gold mineralization and hydrocarbon accumulation all support a coeval model in which the gold originated migrated and precipitated along with the hydrocarbons in an immiscible gold and hydrocarbon bearing basinal fluid system

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

organic matter and gold ore association in a hydrothermal deposit france abstract the aim of this study was to define the part played by organic matter in au ore genesis the possible associations and relations between carbonaceous matter and au were studied at various observation scales drill hole rock sample and microanalysis in an early stage au shear zone type deposit the west viges prospect creuse department france prior work had shown that in this type of deposit au mainly occurs within the structure of arsenopyrite the study of three cores from drill holes revealed a relation between the distribution of the mineralization and the presence of moderately brecciated anthracitic layers within the host volcanosedimentary tuffs chemical assays for au performed on the rock samples after destruction of the carbonaceous material by calcination showed that the au content is nearly always higher after calcination this may indicate that part of the au initially contained in the rock is trapped in the organic phase x ray diffraction spectra on carbonaceous phases isolated from some samples indicated the presence of elemental au these results indicate that like arsenopyrite organic matter is the bearer of au and retains it during conventional acid treatment of the ore

landslide subsurface slip geometry inferred from 3 d surface displacement fields the stability of many large landslides is determined in part by deformation along buried often inaccessible slip surfaces factors such as infiltrating rainfall on the slip surface lead to stability changes yet characterizing the depth and shape of this slip surface is challenging here we examine the hypothesis that the subsurface slip geometry can be constrained by ground surface displacements in concert with two mechanically distinct forward models we estimate a 3 d ground displacement field for the slow moving cleveland corral landslide in california using repeat terrestrial laser scanner data we test the efficacy of two models to estimate slip depth and slip magnitude of the slide a 2 d balanced cross section method and an elastic dislocation model the estimated slip surface depth using both methods matches in situ observations from shear rods installed in the slide within the 0 45 m misfit indicating that these are valuable approaches for investigating landslide geometry and slip behavior

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

bedrock incision rock uplift and threshold hillslopes in the northwestern himalayas the topography of tectonically active mountain ranges reflects a poorly understood competition between bedrock uplift and erosion dating of abandoned river cut surfaces in the northwestern himalayas reveals that the indus river incises through the bedrock at extremely high rates 2 12 mm yr 1 in the surrounding mountains the average angles of hillslopes are steep and essentially independent of erosion rate suggesting control by a common threshold process in this rapidly deforming region an equilibrium is maintained between bedrock uplift and river incision with landsliding allowing hillslopes to adjust efficiently to rapid river down cutting

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

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

geochemistry mineralization structure and permeability of a normal fault zone casino mine alligator ridge district north central nevada abstract we examine the geochemical signature and structure of the keno fault zone to test its impact on the flow of ore mineralizing fluids and use the mined exposures to evaluate structures and processes associated with normal fault development the fault is a moderately dipping normal fault zone in siltstone and silty limestone with 55 100 m of dip slip displacement in north central nevada across strike exposures up to 180 m long 65 m of down dip exposure and 350 m of along strike exposure allow us to determine how faults fractures and fluids interact within mixed lithology carbonate dominated sedimentary rocks the fault changes character along strike from a single clay rich slip plane 10 20 mm thick at the northern exposure to numerous hydrocarbon bearing calcite filled nearly vertical slip planes in a zone 15 m wide at the southern exposure the hanging wall and footwall are intensely fractured but fracture densities do not vary markedly with distance from the fault fault slip varies from pure dip slip to nearly pure strike slip which suggests that either slip orientations may vary on faults in single slip events or stress variations over the history of the fault caused slip vector variations whole rock major minor and trace element analyses indicate that au sb and as are in general associated with the fault zone suggesting that au and silica bearing fluids migrated along the fault to replace carbonate in the footwall and adjacent hanging wall rocks subsequent fault slip was associated with barite and calcite and hydrocarbon bearing fluids deposited at the southern end of the fault no correlation exists at the meter or tens of meter scale between mineralization patterns and fracture density we suggest that the fault was a combined conduit barrier system in which the fault provides a critical connection between the fluid sources and fractures that formed before and during faulting during the waning stages of deposit formation the fault behaved as a localized conduit to hydrocarbon bearing calcite veins the results of this study show that fault zone character may change dramatically over short deposit or reservoir scale distances the presence of damage zones may not be well correlated at the fine scale with geochemically defined regions of the fault even though a gross spatial correlation may exist

coupling of rock uplift and river incision in the namche barwa gyala peri massif tibet geodynamic modeling demonstrates the strong potential for erosion to influence the pattern and style of deformation in active mountain belts but field studies yield conflicting views on the importance of erosion in influencing orogenesis here we compare patterns in river power inferred excess fluvial transport capacity topographic relief precipitation and mineral cooling ages to assess the coupling between surface erosion and rock uplift within the vicinity of the namche barwa gyala peri massif an active antiformal structure within the eastern himalayan syntaxis our rich and dense data set reveals a tight spatial correspondence of fluvial incision potential high relief and young cooling ages the spatial coincidence is most easily explained by a sustained balance between rock uplift and denudation driven by river incision over at least the last 1 m y the yarlung tsangpo brahmaputra river is the largest and most powerful river in the himalaya and two lines of evidence point to its active role in the dynamic interaction of local erosion rock uplift thermal weakening of the lithosphere and deformation 1 whereas along the rest of the himalayan front high relief and high rock uplift rates are essentially continuous the high relief and rapid exhumation in the syntaxis is restricted to a bull s eye pattern exactly where the largest river in the himalaya the yarlung tsangpo brahmaputra has the most energy per unit area available to erode its channel and transport sediment 2 the location of rapid incision on the yarlung tsangpo brahmaputra has been pinned for at least 1 m y and without compensatory uplift of the namche barwa gyala peri massif during this time the river would have eroded headward rapidly incising deeply into tibet

tectonic geomorphology landslides limit mountain relief despite variable forcing by tectonics the height of mountain ranges seems to be limited satellite imagery suggests that landsliding rates adjust to large changes in uplift acting to maintain hillslopes of similar steepness

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

thermodynamics of organic transformations in hydrothermal fluids hydrothermal fluids obtain organic compounds through diverse pathways in submarine systems organic compounds are already dissolved in seawater that is heated and transformed into hydrothermal fluids through water rock reactions microbes inhabiting hydrothermal systems produce metabolites that enter the fluids and cells can be carried into the reaction zones by circulating fluids and pyrolyzed analogous sources of organic compounds can be anticipated in continental systems with the possible addition of novel plant and soil derived organic compounds from the surface in addition hydrothermal systems possess large potentials for abiotic organic synthesis that may add a novel suite of compounds when sedimentary rocks are present ancient biogenic organic matter can be mobilized or transformed by hot fluids these transformations accompany the generation of petroleum coal and other fossil fuels suggesting that expectations for hydrothermal transformations can be built on those that occur in sedimentary basins likewise some types of ore deposition are accompanied by transformations of organic compounds and metal organic complexes may be involved in enhancing the transport of metals in ore forming and other crustal fluids with these thoughts in mind this review starts with an inventory of the types of organic compounds found in hydrothermal systems and some ways that hydrothermal organic compounds are transformed methane can be generated biotically and abiotically from organic or inorganic reactants and since it lacks a carbon carbon bond some researchers would not consider it to be an organic compound nevertheless more data exist for methane in hydrothermal fluids than for any organic compound that fits the definition methane has been quantified in continental and submarine hydrothermal fluids fumarolic gases associated with hydrothermal systems oil field brines deep fluids in sedimentary basins and igneous basement rocks fluids associated with active serpentinization and fluid inclusions in minerals from ore deposits sedimentary basins and deep crustal settings recent examples include

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

review and update of the applications of organic petrology part 2 geological and multidisciplinary applications abstract the present paper is focused on organic petrology applied to unconventional and multidisciplinary investigations and is the second part of a two part review that describes the geological applications and uses of this branch of earth sciences therefore this paper reviews the use of organic petrology in investigations of i ore genesis when organic matter occurs associated with mineralization ii the behavior of organic matter in coal fires self heating and self combustion iii environmental and anthropogenic impacts associated with the management and industrial utilization of coal iv archeology and the nature and geographical provenance of objects of organic nature such as jet amber other artifacts and coal from archeological sites and v forensic science connected with criminal behavior or disasters this second part of the review outlines the most recent research and applications of organic petrology in those fields

geology and geochemistry of three sedimentary rock hosted disseminated gold deposits in guizhou province people s republic of china abstract five sedimentary rock hosted disseminated gold deposits have been discovered since 1980 in southwestern guizhou province prc submicron sized gold is disseminated in silty carbonate and carbonaceous shale host rocks of permian and triassic age arsenic antimony mercury and thallium accompany the gold associated hydrothermal alteration resulted in decarbonatization of limestone silicification and argillization and depletion of base metals barium and many other elements organic material occurs in most host rocks and ores it was apparently devolatilized during a regional heating event that preceded hydrothermal activity and thus was not mobilized during mineralization and did not affect gold deposition the geologic setting of the guizhou deposits includes many features that are similar to those of sedimentary rock hosted deposits of the great basin western united states the heavy element suite that accompanies gold is the same but base metals are even scarcer in the guizhou deposits than they are in u s deposits the guizhou deposits discovered to date are smaller than most u s deposits and have no known spatially associated igneous rocks

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

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

mid holocene cluster of large scale landslides revealed in the southwestern alps by 36cl dating insight on an alpine scale landslide activity abstract although it is generally assumed that the internal structure of a slope e g lithology and rock mass properties inherited faults and heterogeneities etc is preponderant for the progressive development of large scale landslides the ability to identify triggering factors responsible for final slope failures such as glacial debuttressing seismic activities or climatic changes especially when considering landslide cluster at an orogen scale is still debated highlighting in this study the spatial and temporal concordant clustering of deep seated slope failures in the external southwestern alps we discuss and review the possible causes for such wide spread slope instabilities at both local and larger alpine scale high resolution field mapping coupled with electrical resistivity tomography first allows establishing an inventory of large landslides in the southwestern alps determining their structural model precising their depth limit 100 200 m as well as the involved rock volumes 10 7 m 3 we show that they developed in the same geostructural context of thick mudstone layers overlain by faulted limestone and followed a block spread model of deformation that could evolve in rock collapse events cosmic ray exposure dating cre using both 36 cl and 10 be in coexisting limestone and chert respectively has been carried out from the main scarps of six deep seated landslides dsl and leads to landslide failure cre ages ranging from 3 7 to 4 7 ka they highlighted i mainly single and fast ruptures and ii a possible concomitant initiation with a main peak of activity between 3 3 and 5 1 ka centered at ca 4 2 ka because this region was not affected by historical glaciations events landslide triggering by glacial unloading can be excluded the presented data combined with field observations preferentially suggest that these failures were climatically driven and were most likely controlled by high pressure changes in the karstic medium in effect the chronicle of failure ages is concomitant to a well known climatic pulse the 4 2 ka climate event characterized by intense hydrological perturbations associated to the heaviest rainfall period of the entire holocene despite requiring further investigations and discussions the dating of numerous events across the entire alps during the middle holocene period suggests a potential synchronous triggering of several large scale gravitational failures induced by the mid holocene climatic transition

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

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

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