ORCID Profile
0000-0002-8373-635X
Current Organisation
Australian National University
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Publisher: Elsevier BV
Date: 1996
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/SR99078
Abstract: The U-Pb ages of fine-grained zircon separated from 2 dust-dominated soils in the eastern highlands of south-eastern Australia and measured by ion microprobe (SHRIMP) revealed a characteristic age ‘fingerprint’ from which the source of the dust has been determined and by which it will be possible to assess the contribution of dust to other soil profiles. The 2 soils are dominated by zircon 400–600 and 1000–1200 Ma old, derived from Palaeozoic granites and sediments of the Lachlan Fold Belt, but also contain significant components 100–300 Ma old, characteristic of igneous rocks in the New England Fold Belt in northern New South Wales and Queensland. This pattern closely matches that of sediments of the Murray-Darling Basin, especially the Mallee dunefield, suggesting that weathering of rocks in the eastern highlands has contributed large quantities of sediment to the arid and semi-arid inland basins via internally draining rivers of the present and past Murray–Darling River systems, where it has formed a major source of dust subsequently blown eastwards and deposited in the highland soils of eastern Australia.
Publisher: Geological Society of London
Date: 05-1998
Publisher: Informa UK Limited
Date: 18-05-2016
Publisher: Elsevier BV
Date: 12-2004
Publisher: Cambridge University Press (CUP)
Date: 09-1995
Abstract: Paleoceanographic and onshore paleoclimatic changes during the last 59,000 yr are established from three deep-sea sediment cores off northeast New Zealand using an integrated log of sediment texture, CaCO 3 content, palynology, and planktonic and benthic foraminiferal δ 18 O and δ 13 C data, together with dated silicic tephras. These records from the isotopic stage 4-3 boundary to the present record northern New Zealand vegetation history, changes in a subsidiary equatorward flow of Circumpolar Deep Water, and sea-surface temperatures (SSTs) for subtropical water (STW) between latitudes 36°42′ and 35°51′S. Relative to the Holocene, isotopically derived SSTs record average changes of +2°C, -2°C, and -2°C for the 59,000-43,000, 43,000-24,000, and 24,000-12,000 yr time slices, respectively. The apparent +2°C warming for the 59,000-43,000 yr period is interpreted to reflect changes in the dominant depth habitat of Globigerina bulloides in response to upwelling. A -2°C cooling of SSTs during isotope stage 2 is interpreted, in part, to reflect upwelling of cool subsurface water resulting from strong and persistent westerly airflow across New Zealand, with the concomitant enhanced surface-water production of CaCO 3 . Onshore, vegetation consistent with these changes are recorded, with full conifer-hardwood forest prior to 43,000 yr, followed by a change to vegetation implying cooler and drier conditions between 43,000 and 12,000 yr, and a subsequent return to full forest during the Holocene. The sequence of biopelagic and hemipelagic sedimentation observed within these cores reflect oscillation of sea level about a threshold eustatic level that controls the transport of terrigenous detritus offshore. Local variations and interplay of the regional oceanography and morphology and tectonism of the continental shelf will dictate that, relative to present sea level, this threshold eustatic sea level will vary in depth, and hence age, along a continental margin. Data from the New Zealand region reveal an extremely steep meridional thermal gradient across the southern and central New Zealand region during the last glaciation with minor cooling of STW to the north, apart from localized nearshore upwelling zones, but pronounced cooling of subantarctic water to the south of the subtropical convergence zone.
Publisher: Elsevier BV
Date: 06-2010
Publisher: Informa UK Limited
Date: 03-2009
Publisher: Geological Society of America
Date: 1985
Publisher: Informa UK Limited
Date: 30-05-2017
Publisher: Elsevier BV
Date: 1994
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.
Publisher: Informa UK Limited
Date: 03-2005
Publisher: Elsevier BV
Date: 06-2013
Publisher: Informa UK Limited
Date: 03-2005
Publisher: Elsevier BV
Date: 1993
Publisher: Elsevier BV
Date: 1994
Publisher: American Geophysical Union (AGU)
Date: 24-11-2021
DOI: 10.1029/2021GC010094
Abstract: Hematite is a commonly occurring magnetic mineral in nature that has numerous scientific and technological applications. A characteristic property of hematite is a low‐temperature spin‐flop transition called the Morin transition. Above the transition temperature, hematite is a canted antiferromagnet that can carry a remanent magnetization. Below this transition, spin canting disappears and hematite becomes a true antiferromagnet although a small defect moment is usually preserved. We observe Morin transition behavior in natural s les that has not been reported before for hematite. During repeated thermal cycling of a remanent magnetization acquired at room temperature, the remanence intensity at the end of the cycle oscillates between a high remanence state at the end of odd‐numbered cycles and a low remanence state (LRS) at the end of even‐numbered cycles. Alternation of the high and LRSs during repeated thermal cycling points to hysteretic behavior of the spin‐flop process, likely due to sublattice magnetization alignment switches along different easy magnetization axes in s les with preferred crystallographic orientations of hematite particles. We report these observations to seek to expand explanations of the magnetism of hematite.
Publisher: Wiley
Date: 16-01-2014
DOI: 10.1002/ESP.3520
Publisher: Informa UK Limited
Date: 09-2004
Publisher: Elsevier BV
Date: 10-1997
Publisher: Informa UK Limited
Date: 04-2014
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/SR99089
Abstract: In coastal sections at Hallett Cove and Sellicks Beach, south of Adelaide, and at Redbanks section on Kangaroo Island, the Brunhes/Matuyama polarity transition (780 ka) is identified in the strongly oxide-mottled Ochre Cove Formation. At all 3 sections, the Ochre Cove Formation is overlain by a calcareous grey-green aeolian clay, called Ngaltinga Clay, which in turn is overlain by calcareous sediments of the Taringa and Christies Beach Formations. The marked change from an oxide-dominated weathering regime to a carbonate-dominated weathering regime, estimated to have occurred at about 500–600 ka, is interpreted as a major arid shift in regional climates. Similar arid shifts are known from Lake Bungunnia in the Murray Basin and Lake Lefroy in southern Western Australia, where changes from lacustrine clays to evaporites and dune sediments are estimated to have occurred between 400 and 700 ka, and about 500 ka, respectively. An increase in aeolian dust accession in south-eastern Australia, consistent with increased aridity in the interior source area, occurred after 780 ka, and was probably coeval with increased dust input to Tasman Sea sediments since 350 ka. Between 600 and 900 ka, oxygen isotope fluctuations in deep-sea cores showed a pronounced change in frequency, from a 40 ka (obliquity dominated) to a 100 ka (eccentricity dominated) pattern. At the same time, glacial-interglacial litudes increased, with a marked enrichment of glacial d18O values consistent with larger continental based ice-sheets. Colder global temperatures, and lower sea levels during glacials, may have played a part in the mid Pleistocene arid shift recorded in southern Australia. Associated variations in the strength of the warm Leeuwin Current may also have affected regional rainfall patterns in southern Australia.
Publisher: Elsevier BV
Date: 05-2014
Publisher: Geological Society of London
Date: 2010
DOI: 10.1144/SP346.1
Publisher: Elsevier BV
Date: 07-2002
Publisher: Wiley
Date: 04-1983
Publisher: Elsevier BV
Date: 1995
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-01-1999
DOI: 10.1126/SCIENCE.283.5399.197
Abstract: About 140,000 years ago, the breakup of large continental ice sheets initiated the Last Interglacial period. Sea level rose and peaked around 135,000 years ago about 14 meters below present levels. A record of Last Interglacial sea levels between 116,000 years to 136,000 years ago is preserved at reef VII of the uplifted coral terraces of Huon Peninsula in Papua New Guinea. However, corals from a cave situated about 90 meters below the crest of reef VII are 130,000 ± 2000 years old and appear to have grown in conditions that were 6°C cooler than those at present. These observations imply a drop in sea level of 60 to 80 meters. After 130,000 years, sea level began rising again in response to the major insolation maximum at 126,000 to 128,000 years ago. The early (about 140,000 years ago) start of the penultimate deglaciation, well before the peak in insolation, is consistent with the Devils Hole chronology.
Publisher: Elsevier BV
Date: 05-2008
Publisher: Informa UK Limited
Date: 07-2010
Publisher: Elsevier
Date: 2012
Publisher: Elsevier BV
Date: 1996
Publisher: Elsevier BV
Date: 15-04-2002
Publisher: Elsevier BV
Date: 1994
Publisher: Elsevier BV
Date: 1996
Publisher: Informa UK Limited
Date: 03-10-2015
Publisher: Cambridge University Press (CUP)
Date: 03-1990
DOI: 10.1016/0033-5894(90)90017-F
Abstract: A paleomagnetic record of secular variation has been obtained from a 17.4-m-long core drilled from loess in North Island, New Zealand. Three dated rhyolitic tephra occur in the loess core at depths of 1.5, 3.4,and 13.0 m, with ages of 22,500, ≧42,000, and 370,000 years, respectively. The base of the core is estimated to be 500,000 years old, which makes this the longest continuous loess sequence yet described from the Southern Hemisphere. Two periods of anomalously low inclination in the core are correlated with the Mungo Event (ca. 35,000 years ago) and the Emperor Event (ca. 490,000 years ago) the Blake Event (ca. 115,000 years ago) is not recorded.
Publisher: Elsevier BV
Date: 1991
Publisher: Elsevier BV
Date: 08-2005
Publisher: American Association for Cancer Research (AACR)
Date: 15-08-2005
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-01-1999
DOI: 10.1126/SCIENCE.283.5399.202
Abstract: Uplifted coral terraces at Huon Peninsula, Papua New Guinea, preserve a record of sea level, sea-surface temperature, and salinity from the penultimate deglaciation. Remnants have been found of a shallow-water reef that formed during a pause, similar to the Younger Dryas, in the penultimate deglaciation at 130,000 ± 2000 years ago, when sea level was 60 to 80 meters lower than it is today. Porites coral, which grew during this period, has oxygen isotopic values and strontium/calcium ratios that indicate that sea-surface temperatures were much cooler (22° ± 2°C) than either Last Interglacial or present-day tropical temperatures (29° ± 1°C). These observations provide further evidence for a major cooling of the equatorial western Pacific followed by an extremely rapid rise in sea level during the latter stages of Termination II.
Publisher: Elsevier BV
Date: 1986
Publisher: Oxford University Press (OUP)
Date: 22-07-2013
DOI: 10.1093/GJI/GGT206
Publisher: Springer Science and Business Media LLC
Date: 15-06-2020
DOI: 10.1186/S40562-020-00157-5
Abstract: Determination of hematite contributions to sedimentary magnetizations is an important but difficult task in quantitative environmental studies. The poorly crystalline and fine-grained nature of hematite nanoparticles makes quantification of their concentrations in natural environments challenging using mineralogical and spectroscopic methods, while the weak magnetization of hematite and often significant superparamagnetic nanoparticle concentrations make quantification difficult using magnetic remanence measurements. We demonstrate here that much-used magnetic parameters, such as the S -ratio and ‘hard’ isothermal remanent magnetization (HIRM), tend to significantly underestimate relative and absolute hematite contents, respectively. Unmixing of isothermal remanent magnetization (IRM) acquisition curves is among the more suitable approaches for defining magnetic mineral contributions, although it has under-appreciated uncertainties that limit hematite quantification. Diffuse reflectance spectroscopy and other methods can enable relative hematite and goethite content quantification under some conditions. Combined use of magnetic, mineralogical, and spectroscopic approaches provides valuable cross-checks on estimated hematite contents such an integrated approach is recommended here. Further work is also needed to rise to the challenge of developing improved methods for hematite quantification.
Publisher: Elsevier BV
Date: 04-1993
Publisher: Wiley
Date: 10-1995
Publisher: University of Chicago Press
Date: 2000
DOI: 10.1086/314388
Abstract: Apatite fission track thermochronology (AFTT) and paleomagnetic (PM) results have been used to constrain the Late Paleozoic to Cenozoic landscape evolution of the Lachlan Fold Belt (LFB) around the Northparkes copper-gold deposit in east-central New South Wales. The present-day landscape of this region of the LFB is relatively flat with little expression of the underlying rock and has previously been interpreted to indicate long-term stability of the region since the end of LFB orogenesis in the Early Carboniferous. This was presumably borne out by PM analyses from thick weathered horizons within open pits at the mine, which suggested that significant periods of weathering, and hence relative landscape stability, prevailed during the Early to middle Carboniferous and at some time during the Cenozoic. Results from AFTT analyses, however, indicate that the region must have experienced significant episodes of cooling/denudation during the mid-Permian to mid-Triassic and during the early Cenozoic, as well as episodes of heating/burial during the Late Carboniferous to mid-Permian and during the late Mesozoic. When combined, the AFTT and PM results are in fact consistent and indicate that since the late Paleozoic the landscape of the LFB around the Northparkes deposit has evolved through multiple episodes of denudation and deposition as well as periods of relative stability during which the thick weathering horizons formed. Together these results establish a complementary chronological framework that constrains the Late Palaeozoic to Cenozoic landscape evolution of the Northparkes region and highlights the importance of using dual data sets in elucidating the long-term landscape evolution of similar "stable" terranes.
Publisher: Informa UK Limited
Date: 06-1992
Publisher: Cambridge University Press (CUP)
Date: 03-1988
DOI: 10.1016/0033-5894(88)90059-2
Abstract: Strata at Landguard Bluff, near Wanganui, New Zealand preserve a clear record of relative sea-level changes during oxygen-isotope stage 7. Two relative high sea-level stands (during stages 7a about 210,000 yr ago and 7c about 240,000 yr ago) are separated by a relative low sea level (stage 7b) that was at least 32 m lower than present. Pollen analysis of sediment deposited during stage 7b indicates climate at the time was up to 3°C cooler than present. The climate and sea-level evidence from Landguard Bluff are consistent with oxygen-isotopic evidence from deep-sea cores indicating a marked cooling during stage 7, which is closely associated with a summer radiation minimum centered at about 230,000 yr ago in the Northern Hemisphere.
Publisher: Geological Society of London
Date: 2005
Publisher: Oxford University Press (OUP)
Date: 27-08-2014
DOI: 10.1093/GJI/GGU293
Publisher: American Geophysical Union (AGU)
Date: 12-2021
DOI: 10.1029/2021JB023027
Abstract: Hematite carries magnetic signals of interest in tectonic, paleoclimatic, paleomagnetic, and planetary studies. First‐order reversal curve (FORC) diagrams have become an important tool for assessing the domain state of, and magnetostatic interactions among, magnetic particles in such studies. We present here FORC diagrams for erse hematite s les, which provide a catalog for comparison with other studies and explain key features observed for hematite. Ridge‐type signatures typical of uniaxial single‐domain particle assemblages and “kidney‐shaped” FORC signatures, and combinations of these responses, occur commonly in natural and synthetic hematite. Asymmetric features that arise from the triaxial basal plane anisotropy of hematite contribute to vertical spreading in kidney‐shaped FORC distributions and are intrinsic responses even for magnetostatically noninteracting particles. The dominant FORC distribution type in a s le (ridge, kidney‐shaped, or mixture) depends on the balance between uniaxial/triaxial switching. The identified signals explain magnetization switching and anisotropy features that are intrinsic to the magnetic properties of hematite and other materials with multiaxial magnetic anisotropy.
Publisher: Elsevier BV
Date: 04-2010
Publisher: Geological Society of London
Date: 23-04-2018
Publisher: Wiley
Date: 2007
DOI: 10.1002/JQS.1131
Publisher: Elsevier BV
Date: 12-1998
Publisher: Wiley
Date: 02-2010
DOI: 10.1002/JQS.1338
Publisher: Informa UK Limited
Date: 04-1990
Publisher: Informa UK Limited
Date: 03-2001
Publisher: American Geophysical Union (AGU)
Date: 03-2018
DOI: 10.1002/2017GC007091
Publisher: Informa UK Limited
Date: 30-09-2021
Publisher: Informa UK Limited
Date: 12-1993
Publisher: Elsevier BV
Date: 12-1995
Publisher: Elsevier BV
Date: 10-1991
Publisher: Elsevier BV
Date: 10-2022
Publisher: Informa UK Limited
Date: 1984
Publisher: Elsevier BV
Date: 07-2003
Publisher: Elsevier BV
Date: 08-1998
Publisher: Informa UK Limited
Date: 04-1990
Publisher: Elsevier BV
Date: 08-1992
Publisher: Elsevier BV
Date: 10-2009
Publisher: Informa UK Limited
Date: 06-2004
Publisher: Informa UK Limited
Date: 09-1997
Publisher: Informa UK Limited
Date: 12-2001
Publisher: Elsevier BV
Date: 09-2002
Publisher: Elsevier BV
Date: 02-2008
Publisher: Elsevier BV
Date: 1996
Publisher: Elsevier BV
Date: 05-2005
Publisher: Geological Society of America
Date: 2007
DOI: 10.1130/G23247A.1
Publisher: Wiley
Date: 04-1993
Publisher: Elsevier BV
Date: 06-2010
Publisher: Informa UK Limited
Date: 03-1992
Start Date: 2010
End Date: 2011
Funder: Australian Research Council
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Funder: Australian Research Council
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End Date: 2015
Funder: Australian Research Council
View Funded ActivityStart Date: 2014
End Date: 2017
Funder: Australian Research Council
View Funded ActivityStart Date: 2012
End Date: 2012
Funder: Australian Research Council
View Funded ActivityStart Date: 2007
End Date: 2007
Funder: Australian Research Council
View Funded ActivityStart Date: 2008
End Date: 2008
Funder: Australian Research Council
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