late quaternary climates of the australian arid zone a review abstract aridity in australia has generally been associated with glacial intervals of the last few glacial cycles the causes and nature of aridity varied from north to south over the continent in northern and central australia reduced monsoon rain in global cold stages caused lakes and rivers to dry vegetation to become more sparse sand dunes to become active and dust advection to increase while the monsoon is correlated with warmer global temperatures and high sea levels overall the exact timing of the greatest development of the monsoon in stage 5 remains uncertain in southeastern australia the proxy records give a less clear picture while vegetation seems to have been more sparse in cold stages and sand dune activity and dust flux consequently greater records of runoff in rivers and lakes have mixed or opposite behaviour to northern or central australia the nature of aridity in southeastern australia is not analogous to conditions anywhere on the continent today greatly reduced temperatures over the central and southern interior greater influence of snow and periglaciation on runoff high groundwater tables lower rainfall and reduced atmospheric carbon dioxide levels may all have contributed to and interacted to produce the reconstructed picture of a cold sparsely vegetated arid landscape with large rivers and perennial lakes the largest changes in circulation patterns over the glacial cycle probably occurred in the location and or intensity of summer tropical convergence in northern australia over southern australia changes to the temperature and humidity of the westerly circulation have been more significant than the small fluctuations in latitude of the sub tropical high pressure ridge

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

integrating stalagmite vertebrate and pollen sequences to investigate holocene vegetation and climate change in the southern midwestern united states abstract speleothem carbon and oxygen isotopic records from onondaga cave south central missouri and beckham creek cave north central arkansas are compared with the cupola pond and oldfield swamp pollen series from southeastern missouri and the rodgers shelter and modoc shelter vertebrate biostratigraphic sequences from central missouri and southwestern illinois similar and roughly contemporaneous shifts between deciduous forest and steppe indicators throughout the holocene are revealed in each database these independent proxies record steppe conditions between approximately 9000 and 1500 cal yr b p a shift toward lighter speleothem carbon may reflect a change from warm and dry to cool and dry conditions between 4500 and 3000 yr b p the sensitive response of speleothem 13c to changes in vegetation emphasizes their importance as paleoclimate records in an area containing few other millenial scale climate proxies

stable isotope record and its palaeoenvironmental interpretation for a late middle pleistocene speleothem from victoria fossil cave naracoorte south australia abstract a speleothem from victoria fossil cave south australia provides a continuous stable isotope record from 185 to 157 ka oxygen isotope analysis indicates that at commencement of deposition mean annual temperatures were much lower than at present and that between 178 and 162 ka regional surface temperatures were similar to today such high temperatures during an interstadial are surprising but may be attributable to increased continentality due to low sealevels carbon isotope analysis indicates the presence of an active vegetation cover dominated by c3 plants during the interstadial while a sparse vegetation dominated by c4 grasses appears to have been dominant during full glacial conditions variations in moisture availability and vegetation productivity are probably closely related to stages in the precessional cycle

origin of the sedimentary deposits of the naracoorte caves south australia abstract the origin of the sediments located in the naracoorte caves south australia was investigated via the analysis of strontium isotope ratios 87sr 86sr elemental geochemistry and mineralogy sedimentary deposits located in robertson wet blanche and several other chambers in victoria cave are all variable mixes of fine sand and coarse silts which display similar and consistent strontium isotope ratios 0 717 0 725 this suggests that over the 400 ka time frame that these deposits span there has been minimal variation in the source of the clastic sediments increased strontium concentrations for these cave sediments correspond with increasing silt content yet there is no correlation between 87sr 86sr ratios and silt content this implies that the silt sized component of the sediments is the main contributor of strontium to the cave sediments comparisons of 87sr 86sr with regional surficial deposits show a significant correlation between the cave sediments avg 0 7228 n 27 the fine silt lunettes of the bool lagoon area avg 0 7224 n 4 the sandy a horizons of the coonawarra red brown earths rbes avg 0 726 n 5 and holocene age podsolic sand deposits 0 723 these data suggest that there has been substantial flux from this group of deposits to the caves as would be expected considering prevailing winds this relationship is further supported by a strong correlation between many trace elements including ti zr ce and y however variations in clay mineralogy suggest that the fine silt dominated lunettes and padthaway rbes were not significant contributors to the cave deposits hence the detritus entering the caves was more than likely from areas proximal to the cave entrance and was dominated by medium grain sized materials major regional deposits including the coarser grained calcite rich bridgewater formation sands basalts from the lower se padthaway horst granites gambier limestone and metamorphics from the adelaide geosyncline show minimal correlation in 87sr 86sr ratios elemental geochemistry and mineralogy with the cave sediments and are discounted as significant sources in comparison 87sr 86sr ratios for the coorong silty sands 0 717 0 724 lower murray sands 0 727 0 730 and the medium size silt component of the murray darling river system 0 71 0 72 compare favourably with the cave sediments this relationship is further supported by similarities in elemental chemistry and mineralogy thus much of the strontium rich silt that is now located in the naracoorte cave sediments likely originated from the murray darling basin over time this material has been transported to the se of south australia where it mixed with the medium sand component of the regressive dune ridge sequence locally derived organic matter limestone fragments and fossil material to produce the unique deposits that we see evident in many of the chambers of the naracoorte cave system today

expanding the utility of uranium series dating of speleothems for archaeological and palaeontological applications uranium series u series dating of speleothems is frequently used for palaeoclimate studies but its archaeological and palaeontological applications are limited to stratigraphically significant speleothem formations such as flowstones to provide maximum and minimum temporal points this study targeted soda straw stalactites for u series dating in contrast to other speleothem formations soda straw stalactites are fragile have typically short life spans usually only years but rarely up to a few hundred years and are frequently incorporated into cave deposits results of thermal ionisation mass spectrometry tims u series dating of soda straw stalactites from palaeontological excavations at blanche cave south australia show that small dense clean straws tend to yield ages closest to the time of stratigraphic deposition a correlation between soda straw u series ages and radiocarbon ages of charcoal from the site is shown multiple soda straw age determinations for a single stratigraphic unit are required in order to verify age concordance in conjunction with other dating methods u series dating of soda straw stalactites may help to significantly constrain the age of stratigraphic units and associated archaeological and palaeontological deposits in order to provide more robust chronologies here we advocate the collection of soda straw stalactites at future excavations of limestone cave sites

u series dating of bone using the diffusion adsorption model abstract u series dating of bone has suffered problems of reliability since its inception because bone remains an open system with respect to uranium commonly applied a priori assumptions of u uptake such as early uptake or linear uptake are inadequate because they have no physical or chemical bases no means of demonstrating which model is suitable for a particular bone and no intrinsic tests of reliability despite this and numerous examples of anomalous u series dates such assumptions are still routinely applied we address this problem using the diffusion adsorption d a model of u uptake millard and hedges 1996 which incorporates a physicochemical description of u uptake using this model we show how the u uptake of a bone responds to geochemical changes in the burial environment which can lead to phenomena such as the removal of u from bones leaching or u uptake late in their burial history recent uptake and we show how the overall uptake history is reflected in distributions profiles of u and u series isotopes across a bone section we present measurements of u concentration profiles and 230 th 234 u profiles on archeological bone from a number of different sites and burial environments and compare the results to profiles predicted by the d a model bones that have undergone complex uptake histories which include u leaching or recent uptake are identified on the basis of these profiles and rejected as unsuitable for dating for bones that appear to have undergone uptake under constant geochemical conditions the d a model is applied to calculate u series dates with much improved reliability

vegetation and climate change during the last interglacial glacial cycle in western tasmania australia abstract cool temperate phyllocladus aspleniifolius nothofagus cunninghamii rainforest occurred in western tasmania during isotope substage 5e during most of the last glacial stage substage 5d to stage 2 the vegetation was subalpine woodland and shrubland or alpine grassland herbland and heathland montane and subalpine rainforest existed at mid altitude 516 m during substages 5a and 5c during stage 2 the late wisconsin glacial maximum most of western tasmania had alpine grassland and herbland vegetation with areas of sclerophyll woodland and rainforest taxa below 100 m on valley floors near the coast cool temperate rainforest developed again during late glacial times after 14 k 14 c yr bp with maximum development of nothofagus cunninghamii rainforest in the early holocene estimates of temperature depression based on depression of the altitudinally zoned vegetation communities a lapse rate of 0 65 c 100 m and comparison with marine core rc 11 120 from the southwestern sub polar indian ocean indicate that the early stadials substages 5b and 5d were cold and the early interstadials substages 5a and 5c were cool stage 4 was cold and probably fully glacial temperature increased early in stage 3 but then decreased with some fluctuations towards stage 2 the late wisconsin glacial maximum an abrupt increase in temperature of ca 6 c occurred after 14 k 14 c yr bp

the mineral chemistry of new titanates from the jagersfontein kimberlite south africa implications for metasomatism in the upper mantle new members of the crichtonite mineral series are described in which k ba ca and ree are in significant concentrations 5 wt oxides filling the a formula position in am21o38 these phases are chromium 16 wt cr2o3 titanates 58 wt tio2 enriched in zro2 5 wt and constitute a mineral repository for refractory and large ion lithophile elements in the upper mantle the mineral senes coexists with mg cr ilmenite nb cr rutile and ca cr nbzr armalcolite that have equally unusual chemistries kimberlitic crichtonites are depleted in the intermediate lanthanides but highly enriched in lree and hree with chondrite normalized abundances of 103 to 105 crichtonite armalcolite and nb cr rutile occupy a compositional range in tio2 contents bridging the gap between ilmenite and rutile two minerals having a widespread distribution in kimberlites and mantle derived nodule suites in common with other associations and based on similarities in mineral chemistry it is concluded that these minerals formed at p 20 30 kb 900 1100 c by reaction of peridotite with metasomatizing fluids kimberlitic crichtonite may be expressed as spinel cr ferropseudobrookite and armalcolite is equivalent to cr geikielite rutile in the system femg tio2 cr2o3 this system contains a number of cr ti compounds not found as minerals but it is proposed that the ubiquitous occurrence of ilmenite intergrowths in kimberlitic rutile results from decomposition of high pressure pbo2 type crystallographic shear structures the new minerals have exotic chemistries and the high k affinities broaden the scope for the origin of alkalic rocks the generation of highly potassic magmas in the upper mantle and suggest that alkali metasomatism may be pervasive

age and origin of terra rossa soils in the coonawarra area of south australia abstract the famous terra rossa soil in the coonawarra area south australia is dominated by locally derived aeolian detritus which probably accumulated over the last 120 130 ka four soil profiles and associated limestone and lunette deposits were investigated using the following methods mass balance geochemistry of bulk soil samples major and trace elements quantitative x ray diffraction xrd mineralogy strontium isotopes 87 86 as well as grain size analysis and cation exchange capacity these data show that the terra rossa soil from the coonawarra has a thick clayey b horizon which is geochemically homogeneous and dominated by smectite and kaolinite mass balance calculations show unrealistic weathering scenarios when plotted using silicate residuum from the underlying limestone as parent realistic weathering scenarios are produced with fine grained silicate material from local lunette deposits as parent strontium isotopes of silicate residuum from gambier limestone 0 78 contrast strongly with the clayey b horizon 0 726 strontium isotope ratios of silicate material from a local lunette 0 725 are similar to the b horizon soil values strontium isotope ratios from regional geological units indicate that the strontium signature in the lunette and soil b horizon is dominated by weathering products from the palaeozoic kanmantoo shales extensively exposed upwind to the west on kangaroo island and the fleurieu peninsula optical optically stimulated luminescence osl dating of 61 individual quartz grains single aliquot from three samples in the coonawarra soil profile one from the a horizon and two from the b horizon shows that most of the quartz sand grains have been buried for only a few thousand years many of the grains however have been buried for tens of thousands of years with three grains having exposure ages of between 105 and 109 ka the large population of young exposure dates represents quartz sands recently exposed in the a horizon and which have been translocated down to the b horizon the older exposure dates are interpreted as representing grains that were buried during or soon after the accumulation of wind blown silt and clay our current model concerning the timing and conditions of aeolian deposition of the coonawarra soil is that much of it accumulated during the relatively wet last interglacial period around 120 130 ka during that time span it is thought that the playa lunette systems in the low lying areas to the west were particularly active and generated a significant local dust flux

temporal variation of seismicity in a himalayan tectonic block and the 1991 uttarkashi earthquake india spatial and temporal variation of the seismicity between 1970 and august 1991 in the northwestern himalaya and adjoining areas of tibet immediately to the north were investigated using a function of the cn algorithm the aim of the exercise was to detect a pattern which if known earlier could have been used to predict the uttarkashi earthquake of 19 october 1991 in the garhwal himalaya it is observed that strong earthquakes occurring in a block defined by longitudes 75 and 83 e and latitudes 30 and 38 n approximately yield a distinctive pattern of temporal variation in the seismicity for the purpose we conclude from the analysis that the seismicity in the northwestern himalayan segment of the alpide himalayan seismic belt may not be independent of seismicity in southwestern tibet

new u th ages for pleistocene megafauna deposits of southeastern queensland australia arguments over the extinction of pleistocene megafauna have become particularly polarised in recent years causes for the extinctions are widely debated with climate change human hunting and or habitat modification or a combination of those factors being the dominant hypotheses however a lack of a spatially constrained chronology for many megafauna renders most hypotheses difficult to test here we present several new u th dates for a series of previously undated megafauna bearing localities from southeastern queensland australia the sites were previously used to argue for or against various megafauna extinction hypotheses and are the type localities for two now extinct pleistocene marsupials including the giant koala phascolarctos stirtoni the new dating allows the deposits to be placed in a spatially and temporally constrained context relevant to the understanding of australian megafaunal extinctions the results indicate that the joint texas caves megafaunal assemblage is middle pleistocene or older 292 ky the cement mills gore megafaunal assemblage is late pleistocene or older 53 ky and the russenden cave bone chamber texas caves megafaunal assemblage is late pleistocene 55 ky importantly the new results broadly show that the sites date prior to the hypothesised megafaunal extinction window i e 30 50 ky and therefore cannot be used to argue exclusively for or against human climate change extinction models without first exploring their palaeoecological significance on wider temporal and spatial scales

extreme enrichment of high field strength elements in jericho eclogite xenoliths a cryptic record of paleoproterozoic subduction partial melting and metasomatism beneath the slave craton canada an unusual suite of zircon and rutile bearing eclogite xenoliths from the 172 ma jericho kimberlite northwest territories canada displays a peculiar geochemistry highlighted by extreme enrichment of high field strength elements most profound are the large positive nb and zr anomalies that are linked to a high modal abundance of niobian rutile and zircon this peculiar geochemistry combined with results from u pb geochronology requires a complex origin involving east dipping paleoproterozoic subduction and partial melting of oceanic crust beneath the slave craton one or more metasomatic overprints prior to kimberlite entrainment and a mesoproterozoic thermal disturbance in the slave lithospheric mantle possibly linked to mackenzie igneous events

late quaternary vegetation and climate change in southeastern australia palynological evidence from marine core e55 6 abstract palynological analysis of core e55 6 obtained from off shore western victoria provides a record of vegetation and climate change in the southeastern south australian and western victorian region spanning much of the last 125 000 yr an accompanying oxygen isotope record provides a chronology for the sequence the pollen record suggests that maximum effective precipitation occurred during the height of the last interglacial oxygen isotope substage 5e with wet sclerophyll forest and rainforest widespread in the region effective precipitation appears to have decreased during substage 5d promoting the expansion of dry sclerophyll communities then increased slightly during substage 5c with the limited re occurrence of wetter forest types climatic conditions gradually became drier from substage 5b with the replacement of eucalypt dominated forest by more open heath and mallee type communities in the arid glacial conditions of isotopic stage 4 a brief phase of increased effective precipitation occurred during the interstadial stage 3 with limited expansion of eucalyptus followed by a steady decline in effective precipitation and the expansion of open heath and grass communities pollen is very sparse in the top section of the core making environmental interpretation difficult nevertheless it appears that grass and heath communities dominated the region during stage 2 there is no clear record of the holocene due to the presence of mudflow sediments in the top of the core the pollen evidence also suggests that continental shelf exposed as sea levels fell was colonised by a mosaic of coastal vegetation including myrtaceae dominated scrub eucalypt and casuarina woodland asteraceae and chenopodiaceae dominated heath and grassland the charcoal record expressed as a ratio to pollen concentration gives evidence of increased burning during the height of the last interglacial period most likely in response to increased fuel loads with the expansion of eucalypt dominated forest this record also indicates a second phase of increased burning commencing in stage 2 which gives possible evidence for increased anthropogenic activity in the region

optical dating of holocene sediments from a variety of geomorphic settings using single grains of quartz this paper presents an improved method for the optical dating of holocene sediments from a variety of geomorphic settings we have measured the equivalent dose de in individual grains of quartz using green laser light for optical stimulation and have simulated the de distributions for multiple grain synthetic aliquots using the single grain data for 12 samples of known independent age we show that application of a minimum age model to the single grain and small 10 grain aliquot de data provides the most accurate estimate of the burial dose for nine of the samples examined 3 aeolian 5 fluvial and 1 marine the weighted mean de as obtained using the central age model gives rise to burial age overestimates of up to a factor of 10 for these nine samples whether single grains small aliquots or large 100 grain aliquots are used for the other three samples two aeolian and one fluvial application of either the minimum age model or the central age model to the single grain small aliquot and large aliquot de data yields burial ages in accord with the independent age control we infer that these three samples were well bleached at the time of deposition these results show that heterogeneous bleaching of the optical dating signal is commonplace in nature and that aeolian transport offers no guarantee that the sample will be well bleached at the time of deposition we also show that grains sensitive to infrared ir stimulation can give rise to low de values which will result in significant underestimation of the burial dose and hence of the age of deposition we demonstrate that use of a modified single aliquot regenerative dose protocol incorporating ir stimulation prior to green light stimulation deals effectively with contamination by ir sensitive grains we conclude that application of the modified protocol to single grains or small aliquots of quartz using the lowest de population to estimate the burial dose is the best means of obtaining reliable ages for holocene sediments from a wide range of depositional environments d 2003 elsevier b v all rights reserved

u pb zircon and rutile ages from granulite xenoliths in the slave province evidence for mafic magmatism in the lower crust coincident with proterozoic dike swarms zircon and rutile in two garnet bearing mafic granulite xenoliths from a kimberlite in the archean slave province record proterozoic ages similar to the 1 27 ga mackenzie dike swarm or similar to the ca 2 23 2 21 ga malley mckay diabase dike swarms the xenolith sample site currently overlies thick lithosphere more than 700 km to the southeast of the proposed mackenzie plume center because lower crust was effectively shielded from the thermal effects of an upwelling plume by thick lithospheric mantle heat was most likely advected into the lower crust by lateral intrusion of mafic sills over distances of hundreds of kilometres from magma generation zones nearer the plume center

variation and pattern in the responses of mammal faunas to late pleistocene climatic change in southeastern south australia we examined mammal occurrence and variability through the late pleistocene vertebrate fossil deposit of grant hall in victoria fossil cave naracoorte south australia to determine long term patterns of change we compared the composition and relative abundance trends of the assemblage with a nearby middle pleistocene deposit in cathedral cave total species richness did not change through the grant hall sequence dated from 93 8t o 70 5 ka however species relative abundances varied between ecologically divergent species and in some cases between species that demonstrate similar environmental preferences for some species this variation is comparable to that recorded in cathedral cave of those showing similar trends between the two deposits the forest inhabitant pseudomys fumeus recorded an 8 6 decline through grant hall coincident with a 9 7 increase in the dry heath mallee dweller pseudomys apodemoides these patterns indicate that climatic transition from relatively warm moist to cooler drier conditions impacted some species in similar ways through climatic cycles of the past however the majority of the fauna demonstrated complex responses that are individual and variable through time statistical tests of species trends from the grant hall assemblage caution that large fossil samples are required to validate patterns observed copyright 2012 john wiley sons ltd

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

a late pleistocene record of aeolian sedimentation in blanche cave naracoorte south australia abstract we provide geochemical analyses and grain size data for a clearly layered 80 cm thick sedimentary deposit close to a roof collapse in blanche cave near naracoorte in se south australia this deposit contains aeolian material deposited between 40 ka and 14 ka cal bp and which yields airborne sediments spanning the last glacial maximum a period of time with little information for the australian continent the deposit also contains abundant vertebrate fossil material derived from owl pellets accumulation and pitfall entrapment below the studied profile large vertebrate remains are found but are not discussed here no holocene sedimentation occurred at the site examined in the cave and the top of the sequence is capped with a layer that has been anthropologically disturbed and contains exotic pinus pollen chronologies of the deposit were obtained using two dating techniques single stage accelerator mass spectrometer ssams 14c analysis of 23 charcoal samples and optically stimulated luminescence osl dating of quartz from 6 sediment samples the 14c chronology is preferred to describe the history of the deposits since the osl chronology which consistently overestimates the associated radiocarbon dates may be inaccurate due to complexities in calculating dose rates and may in addition represent the timing of sediment deposition through the cave opening rather than sediment transport to the deposit site morphological analysis of single quartz grains and grain size analysis indicate different provenance that is confirmed through the geochemical analyses of bulk sediment major elements were measured by x ray fluorescence xrf trace and rare earth elements by laser ablation inductively coupled plasma mass spectrometry la icp ms and neodymium isotopic ratios were obtained using a thermal ionisation mass spectrometer tims our results indicate that the aeolian material deposited in blanche cave over the 40 14 ka cal bp period originated from different sources across south australia although nd isotopes clearly indicate a close association with sediments of the kanmantoo group outcropping along the eastern portion of the mount lofty ranges and the padthaway ridge further south both being located to the nw and nnw of the cave during the latter part of marine isotope stage 3 conditions were wetter and windblown sediment came from the coastal region just north and south of the coorong lagoon with winds originating from the north northwest at that time woody taxa appear to have vegetated the landscape during the drier phases especially the last glacial maximum sediment came from further inland thus suggesting a different predominant wind direction more from the northwest the deglaciation saw material originating from a more northerly direction

stratigraphy and geochronology of pitfall accumulations in caves and fissures bermuda abstract deep fractures fissures and avens skylights in limestone cave roofs create natural traps for sediments and biota fissures fill quickly with surface sediment and organisms soon after opening debris cones are formed as materials fall wash or drift on air through openings in cave skylights such deposits in admiral s and grand canyon cave bermuda contain distinct beds and are composed of mixtures of sediment and charcoal together with fossils of land snails crabs birds reptiles and bats the pitfall accumulations were periodically sealed over by calcite flowstone a stratigraphic record of surface activity and fauna through both glacial and interglacial periods has been preserved the succession also provides an ideal setting in which to compare several geochronological methods calibrated 14 c ages on charcoal and shells provide dated horizons at 1600 12 800 and about 35 000 14 c yr bp thermal ionization mass spectrometric tims ages on several flowstone layers constrain the entire sequence in the admiral s cave sequence between 126 300 900 yr termination ii and historical times a continuous relative age record generated by amino acid epimerization aae geochronology d alloisoleucine l isoleucine or aile ile on the pulmonate land gastropod poecilozonites verifies the biostratigraphy reveals a minimal degree of mixing between stratigraphic units and establishes an independent temporal link between the subterranean and subaerial deposits of bermuda this convergence between stratigraphy and geochronology yields a precisely dated succession from the oceanic island of bermuda and thus presents a unique opportunity to assess the rates and processes of evolutionary and climate change during that interval

anisotropic upper mantle stratigraphy and architecture of the slave craton the earth s physical properties show a dominantly radial structure which is the result of compositional differentiation isochemical phase changes1 and rheological layering2 rheological layering is perhaps the most difficult to investigate using conventional seismological techniques because the seismic manifestation of this property elastic anisotropy may closely mimic the effects of isotropic heterogeneity3 nonetheless an improved characterization of earth s rheological structure promises important insights into such processes as plate dynamics and continental evolution here i present a methodology for effectively characterizing sharp transitions in anisotropic upper mantle structure using the coda of teleseismic p waves application to seismograms from the slave craton reveals a well developed stratigraphy at least in part anisotropic with major boundaries occurring at nominal depths of 75 135 and 195 km the geometry and sharpness of these discontinuities suggest a structural origin perhaps involving shallow subduction

electron spin resonance dating of the fossil deposits in the naracoorte caves south australia the caves near naracoorte south australia contain one of the richest and most diverse fossil faunal assemblages on the australian continent three sites were selected for electron spin resonance esr dating because clastic fossiliferous sediments were sandwiched between speleothem layers this allows independent age control by highly precise thermal ionization mass spectrometry tims u series dating we find that all esr results agree within the constraints given by the u series dates and allow further refinement of the age of the fauna analysed indicating that most of the fauna in the large victoria cave fossil chamber is twice as old as reported previously our dating results spanning from 280 to 500 ka for the fossil chamber victoria cave to about 125 ka for the grant hall victoria cave and 170 to 280 ka for the fossil chamber cathedral cave indicate little change if any in the megafaunal assemblage from the early middle to the early late pleistocene this changed dramatically after the last interglacial when a large proportion of the megafauna suddenly disappeared copyright 2001 john wiley sons ltd

the late pleistocene duoi u oi cave in northern vietnam palaeontology sedimentology taphonomy and palaeoenvironments this paper describes new fossil materials recovered at the duoi u oi site in december 2003 by a vietnamese french japanese team the duoi u oi cave is located in man duc village 25 km of hoabinh city in northern vietnam it belongs to a karstic network developed in a dark grey micritic marine limestone dated from the lower to the middle triassic the sedimentary fill produced a rich mammalian fauna essentially composed of isolated teeth of middle to large sized mammals artiodactyla perissodactyla proboscidea carnivora rodentia primates and characteristic of late pleistocene the results of the duoi u oi fieldwork are of great interest for the following reasons 1 the biochronological age of the fauna is consistent with 230 th 234 u 238 u dating from the calcitic floors 6673 ka the duoi u oi fauna is thus the oldest well dated modern fauna known for the southeast asian mainland 2 in terms of sedimentology the analysis of the formation of the fossiliferous breccia and that of the processes of deposits shows a close relation between the karstic deposits inside the cave and the deposits in the alluvial terraces the observation of three levels of alluvial terraces associated with three caves situated at 62 10 and 3 m above the present alluvial plain suggests that exokarstic and endokarstic sediments evolved together 3 in terms of palaeobiogeography duoi u oi is the continental fauna showing the strongest resemblance with the late pleistocene faunas from indonesian islands punung gunung dawung lida ajer sibrambang and djambu caves this implies that at the time of duoi u oi ca 70 ka the sundaland was mainly characterised by faunas of modern aspect 4 the analysis of major taphonomic factors that led to the mammal assemblage reveals a combination of selective agents selective role of predators and porcupines selective destruction of age classes for some species selective preservation of fossils due to the deposition processes in the karstic network which contribute to the poor representation of the diversity of the fauna no arguments show that humans present at duoi u oi might have a possible role in the taphonomic process 5 the palaeoenvironmental reconstruction based on the composition of the faunal assemblage suggests a forested area and some open habitats under warm and humid conditions

application of sedimentary and chronological analyses to refine the depositional context of a late pleistocene vertebrate deposit naracoorte south australia cave deposits of infill sediments and associated vertebrate fossils provide a valuable source of information on terrestrial palaeoenvironments climatic conditions and palaeocommunities in the deposits of the naracoorte caves world heritage area such records span the last 500 ka and are renowned for their rich diverse vertebrate assemblages previous research into the grant hall deposit of victoria fossil cave suggested that it may preserve the only peak last interglacial ca 125 ka faunal community within the world heritage area the current work tested this existing model for the age of faunal remains from grant hall using multiple techniques physical and geochemical properties of the visually homogeneous sediments were analysed at regular intervals through the sequence to establish meaningful stratigraphic divisions and sediment provenance optically stimulated luminescence dating of individual quartz grains indicates that sediments accumulated in grant hall from 93 8 to 70 5 ka minimum ages provided by u th dating of fossil teeth 72 3 2 2 to 38 2 0 8 ka are consistent with the luminescence chronology and show that the deposit represents a more recent faunal accumulation than previously modelled for the site u th ages on calcite straws within the deposit are significantly older than the sediments and fossil teeth 500 to 186 4 1 ka as such they provide no further constraint on the chronology of the deposit but do indicate that speleothem deposition was active over much of the middle pleistocene sedimentary analyses resulted in the identification of five depositional units contrasting with previous divisions which were based only on visual observation of the sedimentary sequence sediments within each unit are broadly classified as sandy silts with soil structures and may be indirectly derived from the lunettes of nearby bool lagoon although their ultimate provenance is unknown as a result of this work palaeoenvironmental reconstruction based on fossil remains in the deposit may be more accurately related to prevailing climatic and environmental conditions at the time of accumulation it also contributes to an understanding of the temporal occurrence of regional vertebrate faunas through the late pleistocene reinforcing the value of developing stratigraphically constrained chronologies for cave deposits based on multiple techniques

thermal ionization mass spectrometry u series dating of a hominid site near nanjing china mass spectrometric u series dating of speleothems from tangshan cave combined with ecological and paleoclimatic evidence indicates that nanjing man a typical homo erectus morphologically correlated with peking man at zhoukoudian should be at least 580 k y old or more likely lived during the glacial oxygen isotope stage 16 similar to 620 ka such an age estimate which is similar to 270 ka older than previous electron spin resonance and alpha counting u series dates has significant implications for the evolution of asian h erectus dentine and enamel samples from the coexisting fossil layer yield significantly younger apparent ages that of the enamel sample being only less than one fourth of the minimum age of nanjing man this suggests that u uptake history is far more complex than existing models can handle as a result great care must be taken in the interpretation of electron spin resonance and u series dates of fossil teeth

temporal overlap of humans and giant lizards varanidae squamata in pleistocene australia abstract an obvious but key prerequisite to testing hypotheses concerning the role of humans in the extinction of late quaternary megafauna is demonstrating that humans and the extinct taxa overlapped both temporally and spatially in many regions a paucity of reliably dated fossil occurrences of megafauna makes it challenging if not impossible to test many of the leading extinction hypotheses the giant monitor lizards of australia are a case in point despite commonly being argued to have suffered extinction at the hands of the first human colonisers who arrived by 50 ka it has never been reliably demonstrated that giant monitors and humans temporally overlapped in australia here we present the results of an integrated u th and 14c dating study of a late pleistocene fossil deposit that has yielded the youngest dated remains of giant monitor lizards in australia the site colosseum chamber is a cave deposit in the mt etna region central eastern australia sixteen new dates were generated and demonstrate that the bulk of the material in the deposit accumulated since ca 50 ka the new monitor fossil is minimally 30 ky younger than the previous youngest reliably dated record for giant lizards in australia and for the first time demonstrates that on a continental scale humans and giant lizards overlapped in time the new record brings the existing geochronological dataset for australian giant monitor lizards to seven dated occurrences with such sparse data we are hesitant to argue that our new date represents the time of their extinction from the continent rather we suspect that future fossil collecting will yield new samples both older and younger than 50 ka nevertheless we unequivocally demonstrate that humans and giant monitor lizards overlapped temporally in australia and thus humans can only now be considered potential drivers for their extinction

mid pleistocene cave fills megafaunal remains and climate change at naracoorte south australia towards a predictive model using u th dating of speleothems abstract the limestone caves of the naracoorte region in south australia contain extensive deposits of megafauna rich sediments and intercalated cave formation speleothems high precision thermal ionisation mass spectrometry tims u th dating of flowstones directly associated with several large deposits reveals a distinct cyclicity in the timing of sediment and flowstone depositional events in the naracoorte caves this pattern parallels a cyclical alternation of wet phases and intervening periods with a water deficit over the last 500 ka ayliffe et al 1998 geology 26 147 dates from flowstone interlayers in the fossil deposits coincide with the massive speleothem growth events which characterise wet phases hiatuses in flowstone deposition correlatable through several cave systems imply that water deficits were initiated by regional aridity during full glacial and then extended into the succeeding warmer wetter interglacials clastic deposits in caverns with restricted entrance shafts correlate with hiatuses suggesting many of these deposits contain fauna representative of full glacial and interglacial climates caverns with small openings have often been sealed from the surface and dating has constrained the length of accumulation episodes in several fossil deposits one to less than 20 ka the hydrological regimes and environmental conditions inferred from the timing of speleothem deposition have been used to develop a model for cyclic sediment and bone accumulation in the caverns at naracoorte over the last 400 ka the giant victoria fossil chamber deposit accumulated prior to 200 ka and because its entrance is large it may contain faunas representative of all climatic phases there has been no apparent change in faunal diversity at naracoorte over at least three glacial interglacial cycles of the middle pleistocene

whole rock aminostratigraphy of the coorong coastal plain south australia towards a 1 million year record of sea level highstands the coorong coastal plain in southeastern south australia preserves a long quaternary record of cool water temperate carbonate sedimentation in the form of high wave energy barrier shoreline deposits and associated back barrier lagoon facies that formed during successive sea level highstands whole rock samples of bioclastic skeletal carbonate sand with subordinate quartz were collected from aeolian facies modern and relict foredunes of a holocene embayment fill and from ten pleistocene barriers across the coastal plain in a transect from robe to naracoorte the extent of leucine racemization total acid hydrolysate and free amino acids in the pleistocene skeletal carbonate sand 63 500 m increases monotonically with age and is consistently higher than for entire fossil molluscs from the same allostratigraphic units reflecting the lengthy residence time for bioclasts in this high wave energy environment and sediment recycling from the erosion of older barriers the extent of racemization in the whole rock samples conforms with a model of apparent parabolic racemization kinetics and the calculated ages largely agree with previously determined luminescence ages apart from a possible reinterpretation of the significance of the west naracoorte range the coastal plain succession indicates that interglacial sea levels did not deviate by more than 6 m of present sea level for the mid and late pleistocene thus providing an important framework for quantifying ice volume during sea level highstands and calibrating the oxygen isotope record

quaternary depositional facies in cave entrances and their relation to landscape evolution the example of cuvieri cave eastern brazil abstract the correct determination of sedimentation processes in caves is often complicated by the unique characteristics of cave environments and their relationship to surface soil a study at cuvieri cave has allowed new insights into the dynamics and evolution of these types of sedimentary facies and their relation to the nearby landscape the cave is located in the lagoa santa karst eastern brazil and contains fossiliferous deposits of pleistocene holocene age at the base of three vertical pits near the cave entrance facies analysis was applied to sediments to understand sedimentation process and sediments were described according to their morphology grain size micromorphology chemical composition paleontological content and age results indicate that all deposits present a soil like aspect and although they record several depositional conditions sedimentary structures and textures are similar among different facies as such facies were defined by a combination of matrix color degree of cementation and sedimentological characteristics additionally abundance of fauna remains their taxonomic composition extant vs extinct completeness and degree of individuals articulation was evaluated differences between facies were produced by two main factors i change in source area and transport route from the epikarst to doline colluviation and back to epikarst and ii change in type of sediment cover injected from doline fed soils followed by talus debris and finally soils from modern epikarst the change in both factors is related to the landscape evolution mainly with the development and progressive enlargement and deepening of the nearby doline additionally the change in the type of sediment cover injected could also be related to climatic evolution the complex evolution of cuvieri cave sediments occurred over at least the last 300 kyr and is marked by periods in which entrance opening allowed the incorporation of vertebrate both extinct and extant remains into the sediment detailed multidisciplinary field and laboratory analyses are essential in unraveling the long history of sedimentation in caves providing a framework in which multiple events of sediment input and erosion can be correctly interpreted and related to the evolution of the landscape

mammalian responses to pleistocene climate change in southeastern australia resolving faunal responses to pleistocene climate change is vital for differentiating human impacts from other drivers of ecological change while 90 of australia s large mammals were extinct by ca 45 ka their responses to glacial interglacial cycling have remained unknown due to a lack of rigorous biostratigraphic studies and the rarity of terrestrial climatic records that can be related directly to faunal records we present an analysis of faunal data from the naracoorte caves in southeastern australia which are unique not only because of the species richness and time depth of the assemblages that they contain but also because this faunal record is directly comparable with a 500 k y speleothem based record of local effective moisture our data reveal that despite significant population fluctuations driven by glacial interglacial cycling the species composition of the mammal fauna was essentially stable for 500 k y before the late pleistocene extinctions larger species declined during a drier interval between 270 and 220 ka likely reflecting range contractions away from naracoorte but they then recovered locally persisting well into the late pleistocene because the speleothem record and prior faunal response imply that local conditions should have been favorable for megafauna until at least 30 ka climate change is unlikely to have been the principal cause of the extinctions