'Nature' paper reporting the discovery of 40,000-year-old rock art on the Indonesian island of Sulawesi.
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Abstract Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity,... more
Abstract Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30 ka. During the early glacial period (∼ 30–22 ka) and the Last Glacial Maximum (∼ 22–18 ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial ...
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Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to... more
Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se. We report the preliminary findings of the XAFS studies done on a FMO sample and laboratory ...
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Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to... more
Tellurium is found enriched (relative to the continental crust) in marine ferromanganese (oxyhydr) oxides (FMO) by factors of~ 5000-50000, much higher than any other element including its chemical homologue, Se. We have attempted to investige the mechanism (s) of Te incorporation and its enrichment in FMOs by probing in atomic enviroment using X-ray Absorption Fine Structure (XAFS) spectroscopy and compare the result to that of Se.
Quantifying the rates of landscape evolution in response to climate change is inhibited by the difficulty of dating the formation of continental detrital sediments. We present uranium isotope data for Cooper Creek palaeochannel sediments... more
Quantifying the rates of landscape evolution in response to climate change is inhibited by the difficulty of dating the formation of continental detrital sediments. We present uranium isotope data for Cooper Creek palaeochannel sediments from the Lake Eyre Basin in semi-arid South Australia in order to attempt to determine the formation ages and hence residence times of the sediments.
A 2m-thick spheroidal weathering profile, developed on a quartz diorite in the Rio Icacos watershed (Luquillo Mountains, eastern Puerto Rico), was analyzed for major and trace element concentrations, Sr and Nd isotopic ratios and U-series... more
A 2m-thick spheroidal weathering profile, developed on a quartz diorite in the Rio Icacos watershed (Luquillo Mountains, eastern Puerto Rico), was analyzed for major and trace element concentrations, Sr and Nd isotopic ratios and U-series nuclides (238U–234U–230Th–226Ra). In this profile a 40cm thick soil horizon is overlying a 150cm thick saprolite which is separated from the basal corestone by a∼ 40cm thick rindlet zone.
Abstract Pressure-temperature-time paths followed by arc magmas ascending through the lithosphere dictate the phase assemblage that crystallizes, and hence the compositions of liquid fractionates. Here we use La/Yb and Dy/Yb versus SiO 2... more
Abstract Pressure-temperature-time paths followed by arc magmas ascending through the lithosphere dictate the phase assemblage that crystallizes, and hence the compositions of liquid fractionates. Here we use La/Yb and Dy/Yb versus SiO 2 relationships from selected volcanoes to show that amphibole is an important mineral during differentiation of arc magma. Production of intermediate and silicic arc magmas occurs as magmas stall and cool in the mid-lower crust, where amphibole is stable.
Uranium isotopes can be used to determine the residence time of sediments in a catchment, ie how long they are stored in weathering profiles and transported through the catchment by rivers. We have measured uranium isotopes in sediments... more
Uranium isotopes can be used to determine the residence time of sediments in a catchment, ie how long they are stored in weathering profiles and transported through the catchment by rivers. We have measured uranium isotopes in sediments from palaeochannels of the Murrumbidgee River (Murray-Darling Basin, southeastern Australia) to quantify the variations of sediment residence time over the past 100,000 years.
U-series have proven a particularly powerful and unique tool for looking at dehydration and melting timescales beneath volcanic arcs. The key features of U-series nuclides are (1) their differential mobility and partitioning in melt and... more
U-series have proven a particularly powerful and unique tool for looking at dehydration and melting timescales beneath volcanic arcs. The key features of U-series nuclides are (1) their differential mobility and partitioning in melt and fluids relative to the solid (2) the range of timescales that can be covered thanks to their differing halflives.
Understanding shallow crustal processes in caldera systems is essential for volcanic hazards assessment. Rabaul caldera, Papua New Guinea provides a unique place to study caldera-related eruptions. Volcanic activity has increased over the... more
Understanding shallow crustal processes in caldera systems is essential for volcanic hazards assessment. Rabaul caldera, Papua New Guinea provides a unique place to study caldera-related eruptions. Volcanic activity has increased over the past 500 years with recent eruptions in 1878, 1937–1943 and 1994-present. Intermittent activity over the past 12 years have provided a stratigraphically controlled data set that can be used to monitor short-and long-term changes in magma composition and degassing.
Uranium-series isotopes can be used to address the timescale of weathering processes because these nuclides fractionate during weathering and their abundance is time-dependent. A recent study of suspended particles and colloids in the... more
Uranium-series isotopes can be used to address the timescale of weathering processes because these nuclides fractionate during weathering and their abundance is time-dependent. A recent study of suspended particles and colloids in the Murray-Darling River (SE Australia) shows that, even in an environment characterized by low erosion rates and tectonic stability, the residence time of sediments in the basin (including storage in soils and transport in the river) is only a few thousands of years (Dosseto et al.).