ORCID Profile
0000-0001-9427-3525
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Palaeoclimatology | Geochemistry | Physical Geography and Environmental Geoscience | Climatology (Incl. Palaeoclimatology) | Geochronology And Isotope Geochemistry | Geochronology | Quaternary Environments | Geology | Archaeological Science | Isotope Geochemistry | Surface Processes | Palaeontology (incl. Palynology) | Geochronology | Mineralogy and Crystallography | Atmospheric Sciences | Soil Chemistry | Archaeological Science | Natural Resource Management | Surfacewater Hydrology | Climate Change Processes | Palaeoecology | Water And Sanitary Engineering | Sedimentology |
ANZSRC Socio-Economic Objective (SEO)
Earth sciences | Climate variability | Climate change | Effects of Climate Change and Variability on Australia (excl. Social Impacts) | Climate and Climate Change not elsewhere classified | Expanding Knowledge in the Earth Sciences | Climate Change Models | Ecosystem Adaptation to Climate Change | Effects of Climate Change and Variability on New Zealand (excl. Social Impacts) | Land and water management | Scientific instrumentation | Land and water management | Global Effects of Climate Change and Variability (excl. Australia, New Zealand, Antarctica and the South Pacific) (excl. Social Impacts) | Flora, Fauna and Biodiversity at Regional or Larger Scales | Effects of Climate Change and Variability on the South Pacific (excl. Australia and New Zealand) (excl. Social Impacts) | Expanding Knowledge in History and Archaeology
Related Links
Publications
Tropical Indo-Pacific hydroclimate response to North Atlantic forcing during the last deglaciation as recorded by a speleothem from Sumatra, Indonesia
Publisher: Elsevier BV
Date: 06-2018
Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia's arid margin interpreted from speleothem records (23-15 ka)
Publisher: Copernicus GmbH
Date: 14-06-2017
Abstract: Abstract. Terrestrial data spanning the Last Glacial Maximum (LGM) and deglaciation from the southern Australian region are sparse and limited to discontinuous sedimentological and geomorphological records with relatively large chronological uncertainties. This dearth of records has hindered a critical assessment of the role of the Southern Hemisphere mid-latitude westerly winds on the region's climate during this time period. In this study, two precisely dated speleothem records for Mairs Cave, Flinders Ranges, are presented, providing for the first time a detailed terrestrial hydroclimatic record for the southern Australian drylands during 23–15 ka. Recharge to Mairs Cave is interpreted from the speleothem record by the activation of growth, physical flood layering, and δ18O and δ13C minima. Periods of lowered recharge are indicated by 18O and 13C enrichment, primarily affecting δ18O, argued to be driven by evaporation of shallow soil/epikarst water in this water-limited environment. A hydrological driver is supported by calcite fabric changes. These include the presence of laminae, visible organic colloids, and occasional dissolution features, related to recharge, as well as the presence of sediment bands representing cave floor flooding. A shift to slower-growing, more compact calcite and an absence of lamination is interpreted to represent reduced recharge. The Mairs Cave record indicates that the Flinders Ranges were relatively wet during the LGM and early deglaciation, particularly over the interval 18.9–15.8 ka. This wetter phase ended abruptly with a shift to drier conditions at 15.8 ka. These findings are in agreement with the geomorphic archives for this region, as well as the timing of events in records from the broader Australasian region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position of the westerly winds interpreted from marine core MD03-2611, located 550 km south of Mairs Cave in the Murray Canyons region. The implication is that the mid-latitude westerlies are located further south during the period of enhanced recharge in the Mairs Cave record (18.9–16 ka) and conversely are located further north when greater aridity is interpreted in the speleothem record. A further comparison with speleothem records from the northern Australasian region reveals that the availability of tropical moisture is the most likely explanation driving enhanced recharge, with further lification of recharge occurring during the early half of Heinrich Stadial 1 (HS1), possibly influenced by a more southerly displaced Intertropical Convergence Zone (ITCZ). A rapid transition to aridity at 15.8 ka is consistent with a retraction of this tropical moisture source.
Evidence for obliquity forcing of glacial termination II
Publisher: American Association for the Advancement of Science (AAAS)
Date: 18-09-2009
Abstract: In Milankovich theory, the canonical theory of glaciation and deglaciation, ice sheets wax and wane in response to the amount of summer insolation at a latitude of 65°N, which is consistent with the observed timing of the last deglaciation. The penultimate glaciation behaved quite differently, however. Now, Drysdale et al. (p. 1527 , published online 13 August) offer firmer constraints on the timing of the penultimate deglaciation, by correlating a difficult-to-date marine record of ocean volume to a precisely datable nearby speleothem (terrestrial stalagmite). Ocean volume began to increase about 141,000 years ago, thousands of years before the rise in 65°N summer insolation. Thus, instead of the forcing mechanism proposed by Milankovich, variations in Earth's obliquity may be mostly responsible for the disappearance of ice sheets.
High spatial resolution investigation of nucleation, growth and early diagenesis in speleothems as exemplar for sedimentary carbonates
Publisher: Elsevier BV
Date: 03-2018
Continental aridification and the vanishing of Australia's megalakes
Publisher: Geological Society of America
Date: 02-2011
DOI: 10.1130/G31518.1
Visualising mouse neuroanatomy and function by metal distribution using laser ablation-inductively coupled plasma-mass spectrometry imaging
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC02231B
Abstract: Studying the neuroanatomy of the mouse brain using imaging mass spectrometry and chemometric analysis.
Lateglacial to Holocene trace element record (Ba, Mg, Sr) from Corchia Cave (Apuan Alps, central Italy): Paleoenvironmental implications
Publisher: Wiley
Date: 05-2014
DOI: 10.1002/JQS.2712
An arid-adapted middle Pleistocene vertebrate fauna from south-central Australia
Publisher: Springer Science and Business Media LLC
Date: 2007
DOI: 10.1038/NATURE05471
Abstract: How well the ecology, zoogeography and evolution of modern biotas is understood depends substantially on knowledge of the Pleistocene. Australia has one of the most distinctive, but least understood, Pleistocene faunas. Records from the western half of the continent are especially rare. Here we report on a erse and exceptionally well preserved middle Pleistocene vertebrate assemblage from caves beneath the arid, treeless Nullarbor plain of south-central Australia. Many taxa are represented by whole skeletons, which together serve as a template for identifying fragmentary, hitherto indeterminate, remains collected previously from Pleistocene sites across southern Australia. A remarkable eight of the 23 Nullarbor kangaroos are new, including two tree-kangaroos. The erse herbivore assemblage implies substantially greater floristic ersity than that of the modern shrub steppe, but all other faunal and stable-isotope data indicate that the climate was very similar to today. Because the 21 Nullarbor species that did not survive the Pleistocene were well adapted to dry conditions, climate change (specifically, increased aridity) is unlikely to have been significant in their extinction.
Stalagmite evidence for the onset of the Last Interglacial in southern Europe at 129 ± 1 ka
Publisher: American Geophysical Union (AGU)
Date: 12-2005
DOI: 10.1029/2005GL024658
Effects of clove oil on the stress response of matrinxã (Brycon cephalus) subjected to transport
Publisher: FapUNIFESP (SciELO)
Date: 06-2005
DOI: 10.1590/S0044-59672005000200018
Abstract: Fish transport is one of the most stressful procedures in aquaculture facilities. The present work evaluated the stress response of matrinxã to transportation procedures, and the use of clove oil as an alternative to reduce the stress response to transport in matrinxã (Brycon cephalus). Clove oil solutions were tested in concentrations of 0, 1, 5 and 10 mg/L during matrinxã transportation in plastic bags, supplied with water and oxygen as the usual field procedures in Brazil. Clove oil reduced some of the physiological stress responses (plasma cortisol, glucose and ions) that we measured. The high energetic cost to matrinxã cope with the transport stress was clear by the decrease of liver glycogen after transport. Our results suggest that clove oil (5 mg/l) can mitigate the stress response in matrinxã subjected to transport.
Australasian monsoon response to Dansgaard-Oeschger event 21 and teleconnections to higher latitudes
Publisher: Elsevier BV
Date: 05-2013
Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians
Publisher: Public Library of Science (PLoS)
Date: 14-03-2012
Re-analysis of key evidence in the case for a hemispherically synchronous response to the Younger Dryas climatic event
Publisher: Wiley
Date: 2013
DOI: 10.1002/JQS.2605
Author Correction: Speleothem record attests to stable environmental conditions during Neanderthal–modern human turnover in southern Italy
Publisher: Springer Science and Business Media LLC
Date: 13-07-2020
The antiquity of Nullarbor speleothems and implications for karst palaeoclimate archives
Publisher: Springer Science and Business Media LLC
Date: 24-01-2019
DOI: 10.1038/S41598-018-37097-2
Abstract: Speleothems represent important archives of terrestrial climate variation that host a variety of proxy signals and are also highly amenable to radiometric age determination. Although speleothems have been forming on Earth for at least 400 million years, most studies rely upon the U-Th chronometer which extends only to the mid Pleistocene, leaving important questions over their longer-term preservation potential. To date, older records, exploiting the advantages of the U-Pb chronometer, remain fragmentary ‘snapshots in time’. Here we demonstrate the viability of speleothems as deep time climate archives by showing that a vast system of shallow caves beneath the arid Nullarbor plain of southern Australia, the world’s largest exposed karst terrain, formed largely within the Pliocene epoch, with a median age of 4.2 Ma, and that, in these caves, even the most delicate formations date from this time. The long-term preservation of regional-scale cave networks such as this demonstrates that abundant speleothem archives do survive to permit the reconstruction of climates and environments for much older parts of Earth history than the ~600 ka period to which most previous studies have been limited.
Holocene climate change in arid Australia from speleothem and alluvial records
Publisher: SAGE Publications
Date: 12-07-2010
Abstract: New high-resolution MC-ICPMS U/Th ages and C and O isotopic analyses from a Holocene speleothem in arid south-central Australia provide evidence for increased effective precipitation (EP) relative to present at c. 11.5 ka and c. 8—5 ka, peak moisture at 7—6 ka, and onset of an arid climate similar to present by c. 5 ka. δ 18 O and δ 13 C time-series data exhibit marked ( +1‰) contemporaneous excursions over base-line values of −5.3‰ and −11.0‰, respectively, suggesting pronounced moisture variability during the early middle Holocene ‘climatic optimum’. Optically stimulated luminescence and 14 C ages from nearby terraced aggradational alluvial deposits indicate a paucity of large floods in the Late Pleistocene and at least five large flood events in the last c. 6 kyr, interpreted to mark an increased frequency of extreme rainfall events in the middle Holocene despite overall reduced EP. Increased EP in south-central Australia during the early to middle Holocene resulted from (1) decreased El Niño-Southern Oscillation (ENSO) variability, which reduced the frequency of El Niño-triggered droughts, (2) the prevalence of a more La Niña-like mean climatic state in the tropical Pacific Ocean, which increased available atmospheric moisture, and (3) a southward shift in the Intertropical Convergence Zone (ICTZ), which allowed tropical summer storms associated with the Australian summer monsoon (ASM) to penetrate deeper into the southern part of the continent. The onset of heightened aridity and apparent increase in large flood frequency at c. 5 ka is interpreted to indicate the establishment of an ENSO-like climate in arid Australia in the late Holocene, consistent with a variety of other terrestrial and marine proxies. The broad synchroneity of Holocene climate change across much of the Australian continent with changes in ENSO behavior suggests strong teleconnections amongst ENSO and the other climate systems such as the ASM, Indian Ocean Dipole, and Southern Annular Mode.
Improvements in 230Th dating, 230Th and 234U half-life values, and U–Th isotopic measurements by multi-collector inductively coupled plasma mass spectrometry
Publisher: Elsevier BV
Date: 06-2013
The 4.2 ka event in the central Mediterranean: new data from a Corchia speleothem (Apuan Alps, central Italy)
Publisher: Copernicus GmbH
Date: 22-01-2019
Abstract: Abstract. We present new data on the 4.2 ka event in the central Mediterranean from Corchia Cave (Tuscany, central Italy) stalagmite CC27. The stalagmite was analyzed for stable isotopes (δ13C and δ18O) and trace elements (Mg, U, P, Y), with all proxies showing a coherent phase of reduced cave recharge between ca. 4.5 and 4.1 ka BP. Based on the current climatological data on cyclogenesis, the reduction in cave recharge is considered to be associated with the weakening of the cyclone center located in the Gulf of Genoa in response to reduced advection of air masses from the Atlantic during winter. These conditions, which closely resemble a positive North Atlantic Oscillation (NAO) type of configuration, are associated with cooler and wetter summers with reduced sea warming, which reduced the western Mediterranean evaporation during autumn–early winter, further reducing precipitation.
Hydrological control of the dead carbon fraction in a Holocene tropical speleothem
Publisher: Elsevier BV
Date: 12-2012
The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum
Publisher: Springer Science and Business Media LLC
Date: 09-06-2017
DOI: 10.1038/NCOMMS15425
Abstract: Marine sediment records suggest that episodes of major atmospheric CO 2 drawdown during the last glacial period were linked to iron (Fe) fertilization of subantarctic surface waters. The principal source of this Fe is thought to be dust transported from southern mid-latitude deserts. However, uncertainty exists over contributions to CO 2 sequestration from complementary Fe sources, such as the Antarctic ice sheet, due to the difficulty of locating and interrogating suitable archives that have the potential to preserve such information. Here we present petrographic, geochemical and microbial DNA evidence preserved in precisely dated subglacial calcites from close to the East Antarctic Ice-Sheet margin, which together suggest that volcanically-induced drainage of Fe-rich waters during the Last Glacial Maximum could have reached the Southern Ocean. Our results support a significant contribution of Antarctic volcanism to subglacial transport and delivery of nutrients with implications on ocean productivity at peak glacial conditions.
Enhanced climate instability in the North Atlantic and southern Europe during the Last Interglacial
Publisher: Springer Science and Business Media LLC
Date: 12-10-2018
DOI: 10.1038/S41467-018-06683-3
Abstract: Considerable ambiguity remains over the extent and nature of millennial/centennial-scale climate instability during the Last Interglacial (LIG). Here we analyse marine and terrestrial proxies from a deep-sea sediment sequence on the Portuguese Margin and combine results with an intensively dated Italian speleothem record and climate-model experiments. The strongest expression of climate variability occurred during the transitions into and out of the LIG. Our records also document a series of multi-centennial intra-interglacial arid events in southern Europe, coherent with cold water-mass expansions in the North Atlantic. The spatial and temporal fingerprints of these changes indicate a reorganization of ocean surface circulation, consistent with low-intensity disruptions of the Atlantic meridional overturning circulation (AMOC). The litude of this LIG variability is greater than that observed in Holocene records. Episodic Greenland ice melt and runoff as a result of excess warmth may have contributed to AMOC weakening and increased climate instability throughout the LIG.
Assessing the paleoenvironmental potential of Pliocene to Holocene tufa deposits along the Ghaap Plateau escarpment (South Africa) using stable isotopes
Publisher: Cambridge University Press (CUP)
Date: 07-2015
DOI: 10.1016/J.YQRES.2015.04.008
Abstract: The tufa deposits of the Ghaap Plateau escarpment provide a rich, yet minimally explored, geological archive of climate and environmental history coincident with hominin evolution in South Africa. This study examines the sedimentary and geochemical records of ancient and modern tufas from Buxton-Norlim Limeworks, Groot Kloof, and Gorrokop, to assess the potential of these sediments for providing reliable chronologies of high-resolution, paleoenvironmental information. Chronometric dating demonstrates that tufa formation has occurred from at least the terminal Pliocene through to the modern day. The stable isotope records show a trend toward higher, more variable δ 18 O and δ 13 C values with decreasing age from the end of the Pliocene onwards. The long-term increase in δ 18 O values corresponds to increasingly arid conditions, while increasing δ 13 C values reflect the changing proportion of C 3 /C 4 vegetation in the local environment. Analysis of the Thabaseek Tufa, in particular, provides valuable evidence for reconstructing the depositional and chronological context of the enigmatic Taung Child ( Australopithecus africanus ). Collectively, the results of the present study demonstrate the potential of these deposits for developing high-precision records of climate change and ultimately, for understanding the causal processes relating climate and hominin evolution.
The 8.2 ka event in northern Spain: timing, structure and climatic impact from a multi-proxy speleothem record
Publisher: Copernicus GmbH
Date: 17-06-2022
DOI: 10.5194/EGUSPHERE-2022-386
Abstract: Abstract. The 8.2 ka event is regarded as the most prominent climate anomaly of the Holocene, and is thought to have been triggered by a meltwater release to the North Atlantic that was of sufficient magnitude to disrupt the Atlantic Meridional Overturning Circulation (AMOC). It is most clearly captured in Greenland ice-core records, where it is reported as a cold and dry anomaly lasting ~160 years, from 8.25 ± 0.05 ka BP until 8.09 ± 0.05 ka BP (Thomas et al., 2007). It is also recorded in several archives in the North Atlantic region, however its interpreted timing, evolution and impacts vary significantly. This inconsistency is commonly attributed to poorly constrained chronologies and/or inadequately resolved time series. Here we present a high-resolution speleothem record of early Holocene palaeoclimate from El Soplao Cave in northern Spain, a region pertinent to studying the impacts of AMOC perturbations on south-western Europe. We explore the timing and impact of the 8.2 ka event on a decadal scale by coupling speleothem stable carbon and oxygen isotopic ratios, trace element ratios (Mg / Ca and Sr / Ca) and growth rate. Throughout the entire speleothem record, δ18O variability is related to changes in effective recharge. This is supported by the pattern of changes in δ13C, Mg / Ca and growth rate. The 8.2 ka event is marked as a centennial-scale negative excursion in El Soplao δ18O, starting at 8.19 ± 0.06 ka BP and lasting until 8.05 ± 0.05 ka BP, suggesting increased recharge at the time. Although this is supported by the other proxies, the litude of the changes is minor and largely within the realm of variability over the preceding 1000 years. Further, the shift to lower δ18O leads the other proxies, which we interpret as the imprint of the change in the isotopic composition of the moisture source, associated with the meltwater flux to the North Atlantic. A comparison with other well-dated records from south-western Europe reveals that the timing of the 8.2 ka event was synchronous, with an error-weighted mean age for the onset of 8.23 ± 0.03 ka BP and 8.10 ± 0.05 ka BP for the end of the event. This compares favourably with the NGRIP record. The comparison also reveals that the El Soplao δ18O is structurally similar to the other archives in south-western Europe, and the NGRIP ice-core record.
Correction: Visualising mouse neuroanatomy and function by metal distribution using laser ablation-inductively coupled plasma-mass spectrometry imaging
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5SC90051D
Abstract: Correction for 'Visualising mouse neuroanatomy and function by metal distribution using laser ablation-inductively coupled plasma-mass spectrometry imaging' by Bence Paul et al. , Chem. Sci. , 2015, DOI: 10.1039/c5sc02231b.
Central Mediterranean rainfall varied with high northern latitude temperatures during the last deglaciation
Publisher: Springer Science and Business Media LLC
Date: 17-08-2022
DOI: 10.1038/S43247-022-00509-3
Abstract: Similarly to the effects of current climate change, the last deglaciation (Termination I) rapidly altered northern latitude temperatures and ice-sheet extent, as well as the Atlantic Meridional Overturning Circulation. However, it is still unclear how these changes propagated and impacted the central Mediterranean continental rainfall variability. This prevents a full understanding on how global warming will affect Mediterranean areas in the future. Here, we present a high-resolution reconstruction of rainfall changes in the central Mediterranean across Termination I, based on a novel δ 18 O time series from a southern Italian stalagmite. Across Termination I the availability of Atlantic moisture varied in response to northern latitude temperature increases (decreases) and ice-sheet decreases (increases), promoting a higher (lower) intensity of the Atlantic Meridional Overturning Circulation, and resulting in a relatively wetter (drier) climate in the Mediterranean. In the light of future warming, this study emphasises the role of high-latitude climate changes in causing rainfall variation in highly populated Mediterranean areas.
Geoarchaeological finds below Liang Bua (Flores, Indonesia): A split-level cave system for Homo floresiensis?
Publisher: Elsevier BV
Date: 12-2015
Contemporaneity of Australopithecus , Paranthropus , and early Homo erectus in South Africa
Publisher: American Association for the Advancement of Science (AAAS)
Date: 03-04-2020
Abstract: Fossil hominins from South Africa are enriching the story of early human evolution and dispersal. Herries et al. describe the geological context and dating of the hominin-bearing infilled cave, or palaeocave, at a site called Drimolen in South Africa (see the Perspective by Antón). They focus on the age and context of a recently discovered Homo erectus sensu lato fossil and a Paranthropus robustus fossil, which they dated to ∼2.04 million to 1.95 million years ago. This makes Drimolen one of the best-dated sites in South Africa and establishes these fossils as the oldest definitive specimens of their respective species ever discovered. The age confirms that species of Australopithecus, Paranthropus , and early Homo overlapped in the karst of South Africa ∼2 million years ago. Science , this issue p. eaaw7293 see also p. 34
Coeval dry events in the central and eastern Mediterranean basin at 5.2 and 5.6ka recorded in Corchia (Italy) and Soreq caves (Israel) speleothems
Publisher: Elsevier BV
Date: 11-2014
Dating stalagmites in mediterranean climates using annual trace element cycles
Publisher: Springer Science and Business Media LLC
Date: 04-04-2017
DOI: 10.1038/S41598-017-00474-4
Abstract: Speleothems may preserve geochemical information at annual resolution, preserving information about past hydrology, environment and climate. In this study, we advance information-extraction from speleothems in two ways. First, the limitations in dating modern stalagmites are overcome by refining a dating method that uses annual trace element cycles. It is shown that high-frequency variations in elements affected by prior calcite precipitation (PCP) can be used to date speleothems and yield an age within 2–4% chronological uncertainty of the actual age of the stalagmite. This is of particular relevance to mediterranean regions that display strong seasonal controls on PCP, due to seasonal variability in water availability and cave-air p CO 2 . Second, using the chronology for one stalagmite s le, trace elements and growth-rate are compared with a record of climate and local environmental change i.e. land-use and fire, over the 20 th century. Well-defined peaks in soil-derived trace elements and simultaneous decreases in growth-rate coincide with extreme annual rainfall totals in 1934 and 1974. One of which, 1934, was due to a recorded cyclone. We also find that bedrock-derived elements that are dominated by PCP processes, reflect a well-known period of drying in southwest Australia which began in the 1970’s.
Supplementary material to DQPB: software for calculating disequilibrium U-Pb ages
Publisher: Copernicus GmbH
Date: 30-09-2022
New advances in the dating of speleothems - An introduction
Publisher: Elsevier BV
Date: 12-2012
Synchronous climate change between the Arctic and the Asian and Indo-Australian summer monsoon domains at the Younger Dryas termination
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-12867
Abstract: & & The end of the Younger Dryas (YD) was Earth& #8217 s last major abrupt climate event and is most vividly preserved in the water-isotope (ice & #948 & sup& & /sup& O), calcium (Ca& sup& +& /sup& ) and methane-concentration (CH& sub& & /sub& ) series of Greenland ice cores. Although numerous palaeoclimate records span this transition, surprisingly few have the dating precision necessary to test whether or not abrupt warming in Greenland was accompanied by synchronous climate changes beyond the Arctic. Speleothems, with their exceptional absolute chronologies, are well placed to conduct such a test.& & & & Here we apply a change-point detection algorithm to new and published speleothem & #948 & sup& & /sup& O records of the YD from the Indo-Australian summer monsoon and Asian summer monsoon domains to compare the synchronicity of hydroclimate changes across the YD termination. The algorithm, which identifies the age (and its uncertainty) of a regime shift in a time series, was applied to the 13 - 11 ka interval of each speleothem record. The results yield an error-weighted mean YD-termination age of 11.55 & #177 0.02 ka BP (2& #963 ), supporting the hypothesis of a closely coupled monsoon seesaw. Analysis of the Greenland NGRIP ice-core & #948 & sup& & /sup& O and Ca& sup& +& /sup& records on the GICC05 chronology for the same interval produces a YD-termination age of 11.63 & #177 0.10 ka BP. Although the NGRIP and speleothem ages overlap within uncertainties, this hints at a possible Arctic lead over the tropics. However, if we apply a correction to the GICC05 chronology based on recent ice-core & sup& & /sup& Be and tree-ring & sup& & /sup& C synchronisation, the change-point analysis gives a NGRIP termination age of 11.57 & #177 0.02 ka BP. This revised timing is consistent with the Cariaco Basin greyscale record (11.56 & #177 0.02 ka BP). It also brings the NGRIP and Antarctic WAIS Divide ice-core CH& sub& & /sub& records into perfect alignment across the transition. This assemblage of ages from geographically dispersed regions suggests that hydroclimate changes associated with the YD termination were synchronous, at least to within a couple of decades. It also calls for a revision to the onset age of the Greenlandian Stage (the Pleistocene-Holocene boundary).& &
The Neanderthal in the karst: First dating, morphometric, and paleogenetic data on the fossil skeleton from Altamura (Italy)
Publisher: Elsevier BV
Date: 05-2015
DOI: 10.1016/J.JHEVOL.2015.02.007
Abstract: In 1993, a fossil hominin skeleton was discovered in the karst caves of Lamalunga, near Altamura, in southern Italy. Despite the fact that this specimen represents one of the most extraordinary hominin specimens ever found in Europe, for the last two decades our knowledge of it has been based purely on the documented on-site observations. Recently, the retrieval from the cave of a fragment of bone (part of the right scapula) allowed the first dating of the in idual, the quantitative analysis of a diagnostic morphological feature, and a preliminary paleogenetic characterization of this hominin skeleton from Altamura. Overall, the results concur in indicating that it belongs to the hypodigm of Homo neanderthalensis, with some phenetic peculiarities that appear consistent with a chronology ranging from 172 ± 15 ka to 130.1 ± 1.9 ka. Thus, the skeleton from Altamura represents the most ancient Neanderthal from which endogenous DNA has ever been extracted.
Spatio-temporal evolution of Australasian monsoon hydroclimate over the last 40,000 years
Publisher: Elsevier BV
Date: 05-2019
Pedothem carbonates reveal anomalous North American atmospheric circulation 70,000–55,000 years ago
Publisher: Proceedings of the National Academy of Sciences
Date: 11-01-2016
Abstract: We show for the first time, to our knowledge, that pedogenic (soil) carbonate mineral accumulations can preserve continuous paleoclimate records that rival the temporal resolution of widely used archives, such as speleothems or lake sediments. Using microanalysis of oxygen, carbon, and uranium isotopes coupled with uranium series dating, we find evidence for a distinct shift in atmospheric circulation in North America’s interior from 70,000 to 55,000 years ago, a finding that highlights the influence of large continental ice sheets on atmospheric circulation. Perhaps most significantly, this work shows that pedothems, which are common in arid and semiarid regions around the world, are a rich archive of paleoclimate information for continental landscapes.
Hydrological change in Southern Europe responding to increasing North Atlantic overturning during Greenland Stadial 1
Publisher: Proceedings of the National Academy of Sciences
Date: 11-05-2015
Abstract: This study presents robust evidence of two hydrological phases within the Greenland Stadial 1 (GS-1) cold event (12.8−11.7 ka B.P.) in Southern Europe. We present a well-dated high-resolution speleothem record (Seso Cave, Central Pyrenees) where temperature and hydrological signals are independently reconstructed. Detailed interpretation of stable isotopes and trace elements allow characterizing a first dry period followed, after 12,500 y before 2000 A.D., by more humid conditions. Our findings point to the resumption of the Atlantic overturning circulation as the main mechanism behind the hydrological response in Europe during this mid–GS-1 transition. The second phase, cold in Greenland but humid in Western Europe, represents a new paradigm in the well-established model of dry, cold stadials during the last glacial period.
Re–Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu–Au deposits
Publisher: Informa UK Limited
Date: 08-2008
500 ka precipitation record from southeastern Australia: Evidence for interglacial relative aridity
Publisher: Geological Society of America
Date: 1998
Evidence for Holocene changes in Australian–Indonesian monsoon rainfall from stalagmite trace element and stable isotope ratios
Publisher: Elsevier BV
Date: 15-03-2010
Rapid U-series dating of young fossil corals by laser ablation MC-ICPMS
Publisher: Elsevier BV
Date: 04-2011
Assessing amino acid racemization variability in coral intra-crystalline protein for geochronological applications
Publisher: Elsevier BV
Date: 06-2012
Younger Dryas-Holocene temperature and rainfall history of southern Indonesia from δ18O in speleothem calcite and fluid inclusions
Publisher: Elsevier BV
Date: 06-2010
Multi-proxy constraints on the climatic significance of trace element records from a New Zealand speleothem
Publisher: Elsevier BV
Date: 06-2000
Isotopic and Elemental Imaging of Geological Materials by Laser Ablation Inductively Coupled Plasma-Mass Spectrometry
Publisher: Wiley
Date: 16-11-2007
Timing and dynamics of Late Pleistocene mammal extinctions in southwestern Australia
Publisher: Proceedings of the National Academy of Sciences
Date: 02-12-2010
Abstract: Explaining the Late Pleistocene demise of many of the world's larger terrestrial vertebrates is arguably the most enduring and debated topic in Quaternary science. Australia lost % of its larger species by around 40 thousand years (ka) ago, but the relative importance of human impacts and increased aridity remains unclear. Resolving the debate has been h ered by a lack of sites spanning the last glacial cycle. Here we report on an exceptional faunal succession from Tight Entrance Cave, southwestern Australia, which shows persistence of a erse mammal community for at least 100 ka leading up to the earliest regional evidence of humans at 49 ka. Within 10 millennia, all larger mammals except the gray kangaroo and thylacine are lost from the regional record. Stable-isotope, charcoal, and small-mammal records reveal evidence of environmental change from 70 ka, but the extinctions occurred well in advance of the most extreme climatic phase. We conclude that the arrival of humans was probably decisive in the southwestern Australian extinctions, but that changes in climate and fire activity may have played facilitating roles. One-factor explanations for the Pleistocene extinctions in Australia are likely oversimplistic.
Western Pacific hydroclimate linked to global climate variability over the past two millennia
Publisher: Springer Science and Business Media LLC
Date: 08-06-2016
DOI: 10.1038/NCOMMS11719
Abstract: Interdecadal modes of tropical Pacific ocean-atmosphere circulation have a strong influence on global temperature, yet the extent to which these phenomena influence global climate on multicentury timescales is still poorly known. Here we present a 2,000-year, multiproxy reconstruction of western Pacific hydroclimate from two speleothem records for southeastern Indonesia. The composite record shows pronounced shifts in monsoon rainfall that are antiphased with precipitation records for East Asia and the central-eastern equatorial Pacific. These meridional and zonal patterns are best explained by a poleward expansion of the Australasian Intertropical Convergence Zone and weakening of the Pacific Walker circulation (PWC) between ∼1000 and 1500 CE Conversely, an equatorward contraction of the Intertropical Convergence Zone and strengthened PWC occurred between ∼1500 and 1900 CE . Our findings, together with climate model simulations, highlight the likelihood that century-scale variations in tropical Pacific climate modes can significantly modulate radiatively forced shifts in global temperature.
Southern Hemisphere subtropical drying as a transient response to warming
Publisher: Springer Science and Business Media LLC
Date: 11-02-2019
Evidence of thermophilisation and elevation-dependent warming during the Last Interglacial in the Italian Alps
Publisher: Springer Science and Business Media LLC
Date: 08-02-2018
DOI: 10.1038/S41598-018-21027-3
Abstract: Thermophilisation is the response of plants communities in mountainous areas to increasing temperatures, causing an upward migration of warm-adapted (thermophilic) species and consequently, the timberline. This greening, associated with warming, causes enhanced evapotranspiration that leads to intensification of the hydrological cycle, which is recorded by hydroclimate-sensitive archives, such as stalagmites and flowstones formed in caves. Understanding how hydroclimate manifests at high altitudes is important for predicting future water resources of many regions of Europe that rely on glaciers and snow accumulation. Using proxy data from three coeval speleothems (stalagmites and flowstone) from the Italian Alps, we reconstructed both the ecosystem and hydrological setting during the Last Interglacial (LIG) a warm period that may provide an analogue to a near-future climate scenario. Our speleothem proxy data, including calcite fabrics and the stable isotopes of calcite and fluid inclusions, indicate a +4.3 ± 1.6 °C temperature anomaly at ~2000 m a.s.l. for the peak LIG, with respect to present-day values (1961–1990). This anomaly is significantly higher than any low-altitude reconstructions for the LIG in Europe, implying elevation-dependent warming during the LIG. The enhanced warming at high altitudes must be accounted for when considering future climate adaption strategies in sensitive mountainous regions.
Late Holocene drought responsible for the collapse of Old World civilizations is recorded in an Italian cave flowstone
Publisher: Geological Society of America
Date: 2006
DOI: 10.1130/G22103.1
Accurate dating of tropical South Pacific stalagmites using physical and chemical cycles
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3656
Abstract: & & Climate and environmental events recorded by speleothems are accurately dated by radiometric techniques. However, speleothems from the Tropical Pacific are difficult to date by the U-series radiometric method due to low uranium content and/or multiple sources of & sup& & /sup& Th. This is the case of stalagmites from Atiu, in the Southern Cook Islands Archipelago, which potentially record shifts of the South Pacific Convergence Zone through time and their impact on droughts and floods. Here we constrain the U-series-based chronology using synchrotron & #181 XRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring.& & & & Chronology involving annual laminae counting has, to date, been focused on settings where strong temperature seasonality favours the formation of annual geochemical hysical cycles. In Atiu caves temperature is constant throughout the year (mean & #8764 & #176 C), whereas precipitation exhibits a strong seasonality, with 70% of the mean Total Annual Rainfall (TAR = 1930& #177 mm/yr) occurring from December to May. However, during the drier season (June through November) rainfall amounts are still substantial, which can lead to missing dry seasons in the speleothem record. Moreover, a shallow depth of the caves (5 -10 m) and limited soil cover enhance fast transmission of rain signal into the caves, possibly resulting in the formation of sub-annual growth bands. Thus, the concentration variability of Sr and Mg alone are not sufficient to identify an annual signal.& & & & We integrated, in a multivariate analysis, high resolution (6& #181 m) variations in trace elements analysed by LA-ICP-MS, with optically visible growth bands and two-dimensional Sr-concentration laminae as identified through synchrotron-radiation-based micro XRF mapping. Cycles of [Mg], [Sr], [Na], [Ba] and [P] concentration were counted for three independent transects in a modern stalagmite (Pu17) from Pouatea Cave. This included semi-automated counting of peak positions on in idual elements, as well as on their principal components (PCA). The three independent analytical techniques produced 37 peak counting series, 20 of which were averaged and integrated into a single age model fitting into the uncertainty limits of U/Th dates. This master chronology was used to construct an age model that integrated laminae counting errors with the U/Th uncertainty. The average uncertainty of U& #8211 Th ages included in the age model is ca. 50%, whereas the initial lamina chronology has a maximum error of 15 years (4%), thus decreasing the uncertainty by at least 45%.& & & & Our yearly resolved chronology was then tested against the local rainfall record by using hydrologically sensitive elements Mg, Na and P. High correlation coefficients for each element corroborated the reliability of the age model, paving the way to reconstruct seasonally resolved records from trace element variations in these tropical speleothems.& &
Evidence for global teleconnections in a late Pleistocene speleothem record of water balance and vegetation change at Sudwala Cave, South Africa
Publisher: Elsevier BV
Date: 02-2015
Antiphase response of the Indonesian–Australian monsoon to millennial-scale events of the last glacial period
Publisher: Springer Science and Business Media LLC
Date: 23-11-2022
DOI: 10.1038/S41598-022-21843-8
Abstract: Antiphase behaviour of monsoon systems in alternate hemispheres is well established at yearly and orbital scales in response to alternating sensible heating of continental landmasses. At intermediate timescales without a sensible heating mechanism both in-phase and antiphase behaviours of northern and southern hemisphere monsoon systems are recorded at different places and timescales. At present, there is no continuous, high resolution, precisely dated record of millennial-scale variability of the Indonesian–Australian monsoon during the last glacial period with which to test theories of paleomonsoon behaviour. Here, we present an extension of the Liang Luar, Flores, speleothem δ 18 O record of past changes in southern hemisphere summer monsoon intensity back to 55.7 kyr BP. Negative δ 18 O excursions (stronger monsoon) occur during Heinrich events whereas positive excursions (weaker monsoon) occur during Dansgaard-Oeschger interstadials—a first order antiphase relationship with northern hemisphere summer monsoon records. An association of negative δ 18 O excursions with speleothem growth phases in Liang Luar suggests that these stronger monsoons are related to higher rainfall amounts. However, the response to millennial-scale variability is inconsistent, including a particularly weak response to Heinrich event 3. We suggest that additional drivers such as underlying orbital-scale variability and drip hydrology influence the δ 18 O response.
U/Pb dating of a terminal Pliocene coral from the Indonesian Seaway
Publisher: Elsevier BV
Date: 05-2012
A model for the formation of layered soda-straw stalactites
Publisher: University of South Florida Libraries
Date: 05-2013
Synchronous timing of abrupt climate changes during the last glacial period
Publisher: American Association for the Advancement of Science (AAAS)
Date: 20-08-2020
Abstract: Abrupt climate changes during the last glacial period have been detected in a global array of palaeoclimate records, but our understanding of their absolute timing and regional synchrony is incomplete. Our compilation of 63 published, independently dated speleothem records shows that abrupt warmings in Greenland were associated with synchronous climate changes across the Asian Monsoon, South American Monsoon, and European-Mediterranean regions that occurred within decades. Together with the demonstration of bipolar synchrony in atmospheric response, this provides independent evidence of synchronous high-latitude–to-tropical coupling of climate changes during these abrupt warmings. Our results provide a globally coherent framework with which to validate model simulations of abrupt climate change and to constrain ice-core chronologies.
Publisher Correction: Southern Hemisphere subtropical drying as a transient response to warming
Publisher: Springer Science and Business Media LLC
Date: 17-04-2019
CellSpace: A module for creating spatially registered laser ablation images within the Iolite freeware environment
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2JA10383D
Further geological and palaeoanthropological investigations at the Maludong hominin site, Yunnan Province, Southwest China
Publisher: Springer Science and Business Media LLC
Date: 28-08-2013
U and Pb variability in older speleothems and strategies for their chronology
Publisher: Elsevier BV
Date: 12-2012
Australopithecus sediba at 1.977 Ma and Implications for the Origins of the Genus Homo
Publisher: American Association for the Advancement of Science (AAAS)
Date: 09-09-2011
Abstract: Further U-series dating and the magnetic stratigraphy of the hosting cave deposits show that Australopithecus sediba lived just under 2 million years ago, near or just before the emergence of Homo .
Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia’s arid margin interpreted from speleothem records (23–15 ka)
Publisher: Copernicus GmbH
Date: 21-12-2016
DOI: 10.5194/CP-2016-135
Abstract: Abstract. Terrestrial data spanning the Last Glacial Maximum (LGM) and deglaciation from the southern Australian region are sparse, and limited to discontinuous sedimentological and geomorphological records with relatively large chronological uncertainties. This dearth of records has prevented a critical assessment of the role of the Southern Hemisphere mid-latitude westerly winds on the region’s climate during this time period. In this study, two precisely-dated speleothem records for Mairs Cave, Flinders Ranges, are presented, providing a detailed terrestrial hydroclimatic record for the southern Australian drylands during 23–15 ka for the first time. Enhanced recharge to Mairs Cave is interpreted from the speleothem record by the activation of growth, physical flood layering and δ18O and δ13C minima. Periods of lowered recharge are indicated by isotopic enrichment, primarily affecting δ18O, argued to be driven by evaporation of shallow soil/epikarst water in this water-limited environment. A hydrological driver is supported by calcite fabric changes. The Mairs Cave record indicates that the Flinders Ranges were relatively wet during the LGM and early deglaciation, particularly over the interval 18.9–16 ka. This wetter phase ended abruptly with a shift to drier conditions at 15.8 ka. These findings are in agreement with the geomorphic archives for this region, as well as the timing of events in records from the broader Australasian region. The recharge phases identified in the Mairs Cave record are correlated with, but antiphase to, the position of the westerly winds interpreted from a marine core in the Great Australian Bight. The implication is that the mid-latitude westerlies are located further south during the period of enhanced recharge in the Mairs Cave record (18.9–16 ka), and conversely are located further north when greater aridity is interpreted in the speleothem record. A comparison with speleothem records from the northern Australasian region reveals that the availability of sub-tropical/tropical moisture is the most likely explanation driving enhanced recharge, with further lification of recharge occurring during the early half of Heinrich Stadial 1, possibly influenced by a more southerly-displaced Intertropical Convergence Zone (ITCZ). A rapid transition to aridity at 15.8 ka is consistent with a retraction of this tropical moisture source.
Chronology, stratigraphy and palaeoenvironmental interpretation of a L ate P leistocene to mid‐H olocene cave accumulation on K angaroo I sland,
Publisher: Wiley
Date: 03-05-2013
DOI: 10.1111/BOR.12015
Rapid interhemispheric climate links via the Australasian monsoon during the last deglaciation
Publisher: Springer Science and Business Media LLC
Date: 06-12-2013
DOI: 10.1038/NCOMMS3908
Abstract: Recent studies have proposed that millennial-scale reorganization of the ocean-atmosphere circulation drives increased upwelling in the Southern Ocean, leading to rising atmospheric carbon dioxide levels and ice age terminations. Southward migration of the global monsoon is thought to link the hemispheres during deglaciation, but vital evidence from the southern sector of the vast Australasian monsoon system is yet to emerge. Here we present a 230thorium-dated stalagmite oxygen isotope record of millennial-scale changes in Australian-Indonesian monsoon rainfall over the last 31,000 years. The record shows that abrupt southward shifts of the Australian-Indonesian monsoon were synchronous with North Atlantic cold intervals 17,600-11,500 years ago. The most prominent southward shift occurred in lock-step with Heinrich Stadial 1 (17,600-14,600 years ago), and rising atmospheric carbon dioxide. Our findings show that millennial-scale climate change was transmitted rapidly across Australasia and lend support to the idea that the 3,000-year-long Heinrich 1 interval could have been critical in driving the last deglaciation.
Nano-scale investigation of co-precipitated subglacial calcite and opal, antarctica 
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-3547
Abstract: & & Calcite crusts from the Elephant Hill Moraine (EHM) (76& #176 '35& quot S & & #176 '05& quot E) collected during 1983-84 & were interpreted as formed in subglacial environments influenced by hydrothermalism (Faure et al., 1988). More recently, & sup& & /sup& U enrichment in these crusts was used to suggest that during the warm MIS 11 interglacial (ca. 400 ka), the ice sheet margin at the Wilkes Basin retreated about 700 km inland (Blackburn et al., 2020). Their & sup& & /sup& U data from separate analyses of pure calcite and pure opal crusts suggested that & #8220 connate seawater would impart marine signatures to subglacial waters& #8221 (Blackburn et al., 2020), with the former associated with massive melting during MIS 11. & However, robust U-series dating by Blackburn et al (2020) was only possible on pure end members of opal and calcite, whilst other EHM crusts did not yield reliable ages and were discarded. The inferred MIS11 ice-loss was then based on a model of & sup& & /sup& U accumulation and on those carbonate ages that fit their hypothesis that connate seawater influenced the subglacial environment.& & & & & & & & & Here, we investigated the nanostructure of EMH s les that yielded unreliable U-Th ages, which were too old to fit into the & sup& & /sup& U-based model of MIS11 connate seawater influencing subglacial waters. High-resolution transmission electron microscope images showed a complex history of precipitation, dissolution, re-precipitation, including the co-precipitation of nanocrystalline calcite and opal. Co-precipitation was documented by the inclusion of micrometre-scale opal spherules within calcite crystals whose lattice orientation does not change across the spherules and can be explained by the fluid being extremely enriched in silica. The calcite immediately surrounding the opal spherules was characterized by twins and likely a response to sub-ice sheet stress during their precipitation. The calcite-opal mixture partially replaced pre-existing calcite crystals, which appear broken, corroded and pre-date a final, pure calcite void-filling cement. Clearly, these EHM s les document several stages of crystallization, which imply repeated mobilization of chemical species. Preliminary Fluid Inclusion analyses of the crusts yielded a temperature of about 85& sup& o& /sup& C, which inferred that at one stage calcite precipitation may have been influenced by hydrothermalism associated with volcanism.& Our identification of complex crystallization histories for the Elephant Moraine subglacial carbonates opens up alternative formation hypotheses to that proposed by Blackburn et al. (2020) such as the existence of multiple sources of aqueous solutions. Consequently, it is fraught to infer that all the EMH formed from connate marine waters generated 400 ka without dating of multiple phases of calcite precipitation from each s le.& & & & & & & & & References: Blackburn, T. et al. 2020, Nature, 583 (7817), pp.554-559. Faure, G.& et al, 1988, Nature, 332(6162), pp.352-354.& &
Regional climate variability and ecosystem responses to the last deglaciation in the northern hemisphere from stable isotope data and calcite fabrics in two northern Adriatic stalagmites
Publisher: Elsevier BV
Date: 07-2013
Rapid trace element analysis of speleothems by ELA-ICP-MS
Publisher: Elsevier BV
Date: 07-2006
Supplementary material to "Hydroclimate of the Last Glacial Maximum and deglaciation in southern Australia’s arid margin interpreted from speleothem records (23–15 ka)"
Publisher: Copernicus GmbH
Date: 21-12-2016
Corrections for initial isotopic disequilibrium in the speleothem U-Pb dating method
Publisher: Elsevier BV
Date: 10-2019
Subaqueous speleothems from the Flinders Ranges, South Australia, as palaeohydrological archives for the arid zone
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-16120
Abstract: & & Australia is the driest continent outside of Antarctica yet relatively little is known about its long-term moisture history. Many local palaeoclimate archives suffer preservation problems, particularly in the arid centre of the continent, where weathering and erosion leave behind an incomplete record. In an attempt to redress the paucity of arid-zone palaeoclimate records, we investigate & #8216 endulites& #8217 , subaqueous speleothems that grow episodically according to fluctuations in local groundwater levels. At Mairs Cave (central Flinders Ranges, South Australia), pendulites have formed around stalactites. During the first sustained episode of drowning, the stalactite is veneered by subaqueous calcite, sealing it and preventing further stalactitic growth after water levels fall. Once sealed, the pendulites only record periods of persistent drowning, assumed to correspond to major pluvial episodes.& & & & Age data from two pendulite s les collected from close to the ceiling where the highest water levels have reached reveal two main groundwater & #8216 high-stand& #8217 phases centred on ~67 and ~48 ka, coincident with Southern Hemisphere summer insolation maxima. This suggests that precession-driven southward migration of the ITCZ resulted in regular and persistent incursions of tropical air masses to the central Flinders Ranges. Trace element, stable isotope and growth-rate changes reveal that these orbitally controlled growth intervals are superimposed by regional climate responses to Dansgaard-Oeschger and Heinrich events. The results from Mairs Cave shed new light on the moisture history of central Australia, in particular the competing influences of tropical and middle-latitude circulation systems. This provides a precisely dated regional palaeoclimate template for reconstructing ecosystem changes, understanding human migration/dispersal patterns of the first Australians, and the progressive demise of megafauna. We also highlight the utility of subaqueous speleothems more generally as important archives for investigating arid-zone palaeoclimate.& &
Enhanced rainfall in the Western Mediterranean during deposition of sapropel S1: stalagmite evidence from Corchia cave (Central Italy)
Publisher: Elsevier BV
Date: 02-2007
Palaeoclimatic implications of the growth history and stable isotope (δ18O and δ13C) geochemistry of a Middle to Late Pleistocene stalagmite from central-western Italy
Publisher: Elsevier BV
Date: 11-2004
Correction for Bartolomé et al., Hydrological change in Southern Europe responding to increasing North Atlantic overturning during Greenland Stadial 1
Publisher: Proceedings of the National Academy of Sciences
Date: 24-06-2015
The tip of the iceberg: U-Pb dating shows that cave systems can be twice as old as their surface expression
Publisher: Copernicus GmbH
Date: 26-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-506
Abstract: & & Caves are important fossil repositories providing records extending back over million-year timescales. While the physical processes of cave formation are well understood, a more important parameter to studies of palaeontology, palaeoanthropology and archaeology & #8212 that of the timing of initial cave development and opening & #8212 has proved more difficult to constrain. The Naracoorte Cave Complex (NCC) in southern Australia is a World Heritage site with a rich record of Pleistocene vertebrate fossils, including extinct megafauna, and serves as a natural laboratory in which to investigate these fundamental cave processes. Using U-Th-Pb dating of speleothems we show that the NCC is at least 1.32 million years old, extending the current understanding of initial speleothem formation by ~70% and the antiquity of initial cave development at this site by at least ~20%. We use charcoal and pollen trapped in the same speleothems to place robust constraints on the timing and extent of subsequent cave opening. The findings of this study provide an important means for researchers working on the plethora of fossil-rich sites worldwide to assess the potential upper limit of vertebrate fossil records within caves.& &
Speleothem climate records from deep time? Exploring the potential with an example from the Permian
Publisher: Geological Society of America
Date: 05-2010
DOI: 10.1130/G30354.1
Cave opening and fossil accumulation in Naracoorte, Australia, through charcoal and pollen in dated speleothems
Publisher: Springer Science and Business Media LLC
Date: 26-09-2022
DOI: 10.1038/S43247-022-00538-Y
Abstract: Caves are important fossil repositories which provide records extending back over million-year timescales. While the physical processes of cave formation are well understood, the timing of initial cave development and opening—a more important parameter to studies of palaeontology, palaeoanthropology and archaeology—has proved more difficult to constrain. Here we investigate speleothems from the Naracoorte Cave Complex in southern Australia, with a rich record of Pleistocene vertebrate fossils (including extinct megafauna) and partly World Heritage-listed, using U-Th-Pb dating and analyses of their charcoal and pollen content. We find that, although speleothem formation began at least 1.34 million years ago, pollen and charcoal only began to be trapped within growing speleothems from 600,000 years ago. We interpret these two ages to represent the timing of initial cave development and the subsequent opening of the caves to the atmosphere respectively. These findings demonstrate the potential of U-Th-Pb dating combined with charcoal and pollen as proxies to assess the potential upper age limit of vertebrate fossil records found within caves.
The 8.2 ka event in northern Spain: timing, structure and climatic impact from a multi-proxy speleothem record
Publisher: Copernicus GmbH
Date: 19-10-2022
Abstract: Abstract. The 8.2 ka event is regarded as the most prominent climate anomaly of the Holocene and is thought to have been triggered by a meltwater release to the North Atlantic that was of sufficient magnitude to disrupt the Atlantic Meridional Overturning Circulation (AMOC). It is most clearly captured in Greenland ice-core records, where it is reported as a cold and dry anomaly lasting ∼ 160 years, from 8.25 ± 0.05 until 8.09 ± 0.05 ka (Thomas et al., 2007). It is also recorded in several archives in the North Atlantic region however, its interpreted timing, evolution and impacts vary significantly. This inconsistency is commonly attributed to poorly constrained chronologies and/or inadequately resolved time series. Here we present a high-resolution speleothem record of early Holocene palaeoclimate from El Soplao Cave in northern Spain, a region pertinent to studying the impacts of AMOC perturbations on south-western Europe. We explore the timing and impact of the 8.2 ka event on a decadal scale by coupling speleothem stable carbon and oxygen isotopic ratios, trace element ratios (Mg / Ca and Sr / Ca), and growth rate. Throughout the entire speleothem record, δ18O variability is related to changes in effective recharge. This is supported by the pattern of changes in δ13C, Mg / Ca and growth rate. The 8.2 ka event is marked as a centennial-scale negative excursion in El Soplao δ18O, starting at 8.19 ± 0.06 ka and lasting until 8.05 ± 0.05 ka, suggesting increased recharge at the time. Although this is supported by the other proxies, the litude of the changes is minor and largely within the realm of variability over the preceding 1000 years. Further, the shift to lower δ18O leads the other proxies, which we interpret as the imprint of the change in the isotopic composition of the moisture source, associated with the meltwater flux to the North Atlantic. A comparison with other well-dated records from south-western Europe reveals that the timing of the 8.2 ka event was synchronous, with an error-weighted mean age for the onset of 8.23 ± 0.03 and 8.10 ± 0.05 ka for the end of the event. This compares favourably with the North Greenland Ice Core Project (NGRIP) record. The comparison also reveals that the El Soplao δ18O is structurally similar to the other archives in south-western Europe and the NGRIP ice-core record.
The World Heritage Naracoorte Caves beyond 500 ka: U-Pb dating and charcoal analysis from speleothems with implications for Pleistocene vertebrate fossil deposits
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-4488
Abstract: & & Under the current rapid global warming, studying how environments responded to past climate change becomes increasingly important to better understand what impact climate variability has on regional flora and fauna. Our new multi-proxy study to the World Heritage Naracoorte Caves in southern Australia provides a unique window into the past climate as they are heavily decorated with speleothems but also contain in-fill deposits rich in Pleistocene vertebrate fossils including the extinct Australian megafauna. Until now, these speleothems have been dated using U-Th series and the fossil-bearing sediments with Optical Stimulated Luminescence and Electro Spin Resonance techniques, but only up to ca. 500 ka. We have U-Pb dated speleothems from the Naracoorte Caves for the first time and extended the record beyond 500 ka. We combined precise chronology with analyses of pollen and charcoal within the speleothems which allows us to better understand how southern Australia& #8217 s climate and its vegetation changed during the Quaternary. It also provides a unique insight into the timing and extent of cave opening with important potential for much older vertebrate fossil deposits than previously thought.& &
High-resolution stalagmite reconstructions of Australian-Indonesian monsoon rainfall variability during Heinrich stadial 3 and Greenland interstadial 4
Publisher: Elsevier BV
Date: 02-2011
Glacio-lacustrine aragonite deposition, meltwater evolution and glacial history during isotope stage 3 at Radok Lake, Amery Oasis, northern Prince Charles Mountains, East Antarctica
Publisher: Cambridge University Press (CUP)
Date: 29-06-2007
DOI: 10.1017/S0954102007000466
Abstract: The late Quaternary glacial history of the Amery Oasis, and Prince Charles Mountains is of significant interest because about 10% of the total modern Antarctic ice outflow is discharged via the adjacent Lambert Glacier system. A glacial thrust moraine sequence deposited along the northern shoreline of Radok Lake between 20–10 ka bp , overlies a layer of thin, aragonite crusts which provide important constraints on the glacial history of the Amery Oasis. The modern Radok Lake is fed by the terminal meltwaters of the alpine Battye Glacier. The aragonite crusts were deposited in shallow water of ancestral Radok Lake 53 ka bp , during the A3 warm event in Isotope Stage 3. Oxygen isotope (δ 18 O) analysis of the last glacial-age aragonite crusts indicates that they precipitated from freshwater with a δ 18 O SMOW composition of -36%, which is 8% more depleted than the present water (-28%) in Radok Lake. A regional oxygen isotope (δ 18 O) and elevation relationship for snow is used to determine the source of meltwater and glacial ice in Radok Lake during the A3 warm event. This relationship indicates that Radok Lake received meltwater from the confluence of both Battye Glacier ice and an expansion of grounded western Lambert Glacier ice in the Amery embayment.
Abrupt increase in east Indonesian rainfall from flooding of the Sunda Shelf ~9500years ago
Publisher: Elsevier BV
Date: 08-2013
A Detailed 31,000-Year Record of Climate and Vegetation Change, from the Isotope Geochemistry of Two New Zealand Speleothems
Publisher: Cambridge University Press (CUP)
Date: 09-1998
Abstract: Uranium-series dating and stable isotope analyses of two speleothems from northwest Nelson, New Zealand, record changes in regional climate and local forest extent over the past 31,000 years. Oxygen isotope variation in these speleothems primarily represents changes in the meteoric waters falling above the caves, possibly responding to latitudinal changes in the position of the Subtropical Front in the Tasman Sea. Seven positive excursions can be identified in the oxygen isotope record, which coincide with periods of glacier advance, known to be sensitive to northward movement of the Subtropical Front. Four glacier advances occurred during oxygen isotope stage 2, with the most extreme glacial conditions centered on 19,000 cal yr B.P. An excursion in the oxygen isotope record from 13,800 to 11,700 cal yr B.P. provides support for a previously identified New Zealand glacier advance at the time of the Younger Dryas Stade, but suggests it began slightly before the Younger Dryas as recorded in Greenland ice cores. Carbon isotope variations in the speleothems record changes in forest productivity, closely matching existing paleovegetation records. On the basis of vegetation changes, stage 2 glacial climate conditions terminated abruptly in central New Zealand, from 15,700 to 14,200 cal yr B.P. Evidence of continuous speleothem growth at one site suggests that depression of the local treeline was limited to 600–700 m below its present altitude, throughout the last 31,000 years.
Pliocene reversal of late Neogene aridification
Publisher: Proceedings of the National Academy of Sciences
Date: 08-02-2016
Abstract: The warm climates of the Pliocene epoch are considered our best analog for a future anthropogenic greenhouse world. However, understanding of the nature of Pliocene climate variability and change on land is currently limited by the poor age control of most existing terrestrial climate archives. We present a radiometrically dated history of the evolution of Southern Hemisphere vegetation and hydroclimate from the latest Miocene to the middle Pliocene. These data reveal a sharp increase in precipitation in the Early Pliocene, which drove complete vegetation turnover. The development of warm, wet early Pliocene climates clearly reversed a long-term Southern Hemisphere trend of late Neogene cooling and aridification, highlighting the question of what initiated this sustained, ∼1.5-My-long interval of warmth.
Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region
Publisher: Geological Society of America
Date: 06-2015
DOI: 10.1130/G36595.1
Quaternary climatic instability in south-east Australia from a multi-proxy speleothem record
Publisher: Wiley
Date: 08-2014
DOI: 10.1002/JQS.2734
High-resolution U-Pb dating of an Early Pleistocene stalagmite from Corchia Cave (central Italy)
Publisher: Elsevier BV
Date: 12-2012
Towards a Method for Quantitative LA ‐ICP ‐MS Imaging of Multi‐Phase Assemblages: Mineral Identification and Analysis Correction Procedures
Publisher: Wiley
Date: 23-05-2014
Supplementary material to The 8.2 ka event in northern Spain: timing, structure and climatic impact from a multi-proxy speleothem record
Publisher: Copernicus GmbH
Date: 17-06-2022
Speleothem record attests to stable environmental conditions during Neanderthal–modern human turnover in southern Italy
Publisher: Springer Science and Business Media LLC
Date: 06-07-2020
Stalagmite evidence for the precise timing of North Atlantic cold events during the early last glacial
Publisher: Geological Society of America
Date: 2007
DOI: 10.1130/G23161A.1
Robust chronological reconstruction for young speleothems using radiocarbon
Publisher: Elsevier BV
Date: 12-2012
Erratum to Re-analysis of key evidence in the case for a hemispherically synchronous response to the younger dryas climatic event [Journal of Quaternary Science 28 8-12]
Publisher: Wiley
Date: 13-02-2013
DOI: 10.1002/JQS.2621
DQPB: software for calculating disequilibrium U-Pb ages
Publisher: Copernicus GmbH
Date: 30-09-2022
Abstract: Abstract. DQPB is software for calculating U-Pb ages while accounting for the effects of radioactive disequilibrium among intermediate nuclides of the U-series decay chains. The software is written in Python and distributed both as a pure Python package, and a stand-alone GUI application that integrates with standard Microsoft Excel spreadsheets. The software implements disequilibrium U-Pb equations to compute ages using various approaches, including concordia-intercept ages on a Tera-Wasserburg diagram, disequilibrium U-Pb isochron ages, Pb/U ages based on single analyses, and modified 207Pb ages. These age calculation approaches are tailored toward young materials that cannot reasonably be assumed to have attained radioactive equilibrium at the time of analysis, although they may also be applied to older materials where disequilibrium is no longer analytically resolvable. The software allows users to implement a variety of regression algorithms using both classical and robust statistics approaches, compute weighted average ages, and construct customisable, publication-ready plots of U-Pb age data. Age uncertainties are propagated using Monte Carlo methods.
Mammalian responses to Pleistocene climate change in Southeastern Australia
Publisher: Geological Society of America
Date: 2007
DOI: 10.1130/G23070A.1
Increasing Australian-Indonesian monsoon rainfall linked to early Holocene sea-level rise
Publisher: Springer Science and Business Media LLC
Date: 02-08-2009
DOI: 10.1038/NGEO605
Precise microsampling of poorly laminated speleothems for U-series dating
Publisher: Elsevier BV
Date: 12-2012
Stratigraphic evidence for a pluvial phase between ca 8200-7100 ka from Renella cave (Central Italy)
Publisher: Elsevier BV
Date: 02-2011
Improved laser ablation U‐Pb zircon geochronology through robust downhole fractionation correction
Publisher: American Geophysical Union (AGU)
Date: 03-2010
DOI: 10.1029/2009GC002618
Vegetation and Climate Change in Southwestern Australia During the Last Glacial Maximum
Publisher: American Geophysical Union (AGU)
Date: 13-02-2019
DOI: 10.1029/2018GL080832
Abstract: The nature and duration of the Last Glacial Maximum (LGM) in Australia are poorly understood, with little regional agreement on the timing and direction of LGM climate changes. One reason for this is that Australian Late Pleistocene terrestrial sediments typically are both sparse and inorganic, inhibiting the development of detailed radiocarbon chronologies. To address this problem, we extracted fossil pollen from radiometrically dated stalagmites collected in southwest Western Australia. Our pollen record, supported by 30 U‐Th dates, reveals the vegetation response to Late Pleistocene climates between ~34 and 14 ka, through the body of the LGM. Before ~28 ka, sclerophyll forests were more open than today, but at ~28 ka forest cover was essentially eliminated, and treeless conditions were maintained until progressive reforestation at ~17.5 ka. This ~10‐ka‐long full glacial episode correlates with other mid‐high latitude Southern Hemisphere records, suggesting that LGM environmental changes were closely coordinated across the hemisphere.
A composite annual-resolution stalagmite record of North Atlantic climate over the last three millennia
Publisher: Springer Science and Business Media LLC
Date: 11-06-2015
DOI: 10.1038/SREP10307
Abstract: Annually laminated stalagmites can be used to construct a precise chronology and variations in laminae thickness provide an annual growth-rate record that can be used as a proxy for past climate and environmental change. Here, we present and analyse the first composite speleothem annual growth-rate record based on five stalagmites from the same cave system in northwest Scotland, where precipitation is sensitive to North Atlantic climate variability and the winter North Atlantic Oscillation (NAO). Our 3000-year record confirms persistently low growth-rates, reflective of positive NAO states, during the Medieval Climate Anomaly (MCA). Another persistently low growth period occurring at 290-550 CE coincides with the European Migration Period and a subsequent period of sustained fast growth-rate (negative NAO) from 600-900 AD provides the climate context for the Viking Age in northern and western Europe.
Partitioning of Mg, Sr, Ba and U into a subaqueous calcite speleothem
Publisher: Elsevier BV
Date: 11-2019
Iolite: Freeware for the visualisation and processing of mass spectrometric data
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1JA10172B
DQPB: software for calculating disequilibrium U–Pb ages
Publisher: Copernicus GmbH
Date: 20-04-2023
DOI: 10.5194/GCHRON-5-181-2023
Abstract: Abstract. Initial radioactive disequilibrium amongst intermediate nuclides of the U decay chains can have a significant impact on the accuracy of U–Pb ages, especially in young s les. For s les that can reasonably be assumed to have attained radioactive equilibrium at the time of analysis, a relatively straightforward correction may be applied. However, in younger materials where this assumption is unreasonable, it is necessary to replace the familiar U–Pb age equations with more complete expressions that account for growth and decay of intermediate nuclides through time. DQPB is software for calculating U–Pb ages while accounting for the effects of radioactive disequilibrium among intermediate nuclides of the U decay chains. The software is written in Python and distributed as both a pure Python package and a stand-alone graphical user interface (GUI) application that integrates with standard Microsoft Excel spreadsheets. The software implements disequilibrium U–Pb equations to compute ages using various approaches, including concordia intercept ages on a Tera–Wasserburg diagram, U–Pb isochron ages, Pb*/U ages based on single aliquots, and 207Pb-corrected ages. While these age-calculation approaches are tailored toward young s les that cannot reasonably be assumed to have attained radioactive equilibrium at the time of analysis, they may also be applied to older materials where disequilibrium is no longer analytically resolvable. The software allows users to implement a variety of regression algorithms based on both classical and robust statistical approaches, compute weighted average ages and construct customisable, publication-ready plots of U–Pb age data. The regression and weighted average algorithms implemented in DQPB may also be applicable to other (i.e. non-U–Pb) geochronological datasets.
A continuous stable isotope record from the penultimate glacial maximum to the Last Interglacial (159-121ka) from Tana Che Urla Cave (Apuan Alps, central Italy)
Publisher: Cambridge University Press (CUP)
Date: 09-2014
DOI: 10.1016/J.YQRES.2014.05.005
Abstract: Relatively few radiometrically dated records are available for the central Mediterranean spanning the marine oxygen isotope stage 6–5 (MIS 6–5) transition and the first part of the Last Interglacial. Two flowstone cores from Tana che Urla Cave (TCU, central Italy), constrained by 19 U/Th ages, preserve an interval of continuous speleothem deposition between ca. 159 and 121 ka. A multiproxy record (δ 18 O, δ 13 C, growth rate and petrographic changes) obtained from this flowstone preserves significant regional-scale hydrological changes through the glacial/interglacial transition and multi-centennial variability (interpreted as alternations between wetter and drier periods) within both glacial and interglacial stages. The glacial stage shows a wetter period between ca. 154 and 152 ka, while the early to middle Last Interglacial period shows several drying events at ca. 129, 126 and 122 ka, which can be placed in the wider context of climatic instability emerging from North Atlantic marine and NW European terrestrial records. The TCU record also provides important insights into the evolution of local environmental conditions (i.e. soil development) in response to regional and global-scale climate events.
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