School of Earth Sciences - Research Publications
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ItemNo Preview AvailableUse of 16S rRNA gene based clone libraries to assess microbial communities potentially involved in anaerobic methane oxidation in a Mediterranean cold seep(SPRINGER, 2007-04)This study provides data on the diversities of bacterial and archaeal communities in an active methane seep at the Kazan mud volcano in the deep Eastern Mediterranean sea. Layers of varying depths in the Kazan sediments were investigated in terms of (1) chemical parameters and (2) DNA-based microbial population structures. The latter was accomplished by analyzing the sequences of directly amplified 16S rRNA genes, resulting in the phylogenetic analysis of the prokaryotic communities. Sequences of organisms potentially associated with processes such as anaerobic methane oxidation and sulfate reduction were thus identified. Overall, the sediment layers revealed the presence of sequences of quite diverse bacterial and archaeal communities, which varied considerably with depth. Dominant types revealed in these communities are known as key organisms involved in the following processes: (1) anaerobic methane oxidation and sulfate reduction, (2) sulfide oxidation, and (3) a range of (aerobic) heterotrophic processes. In the communities in the lowest sediment layer sampled (22-34 cm), sulfate-reducing bacteria and archaea of the ANME-2 cluster (likely involved in anaerobic methane oxidation) were prevalent, whereas heterotrophic organisms abounded in the top sediment layer (0-6 cm). Communities in the middle layer (6-22 cm) contained organisms that could be linked to either of the aforementioned processes. We discuss how these phylogeny (sequence)-based findings can support the ongoing molecular work aimed at unraveling both the functioning and the functional diversities of the communities under study.
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ItemGeodynamic benchmarking tests in HPC(Australian Partnership for Advanced Computing, 2005)The increase in large science focused computational frameworks has raised many issues involving the ability to maintain accurate scientific benchmarks throughout the ongoing evolution of the code. These science based tests allow not only developers access to the latest updates, but the science users as well. It is these scientific tests required for geodynamic code benchmarking in a HPC environment that are investigated. The importance of benchmarking in computational science, for both quality assurance and reliability, is discussed and a case study for thermochemical convection modelling is presented. The implementation of automated testing for science units is described with particular attention to the problems arising from science tests compared to traditional computational tests.
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ItemThe hot southern continent: Heat flow and heat production in Australian Proterozoic terranes(Geological Society of America, 2003-01-01)
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ItemNo Preview AvailableRevised stratigraphy of the Blanchetown Clay, Murray Basin: age constraints on the evolution of paleo Lake Bungunnia(TAYLOR & FRANCIS LTD, 2009)
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ItemNo Preview AvailableDistribution of Palaeozoic reworking in the Western Arunta Region and northwestern Amadeus Basin from 40Ar/39Ar thermochronology: implications for the evolution of intracratonic basins(WILEY, 2009-06)ABSTRACT The Centralian Superbasin in central Australia is one of the most extensive intracratonic basins known from a stable continental setting, but the factors controlling its formation and subsequent structural dismemberment continue to be debated. Argon thermochronology of K‐feldspar, sensitive to a broad range of temperatures (∼150 to 350 °C), provides evidence for the former extent and thickness of the superbasin and points toward thickening of the superbasin succession over the now exhumed Arunta Region basement. These data suggest that before Palaeozoic tectonism, there was around 5–6 km of sediment present over what is now the northern margin of the Amadeus Basin, and, if the Centralian superbasin was continuous, between 6 and 8 km over the now exhumed basement.40Ar/39Ar data from neoformed fine‐grained muscovite suggests that Palaeozoic deformation and new mineral growth occurred during the earliest compressional phase of the Alice Springs Orogeny (ASO) (440–375 Ma) and was restricted to shear zones. Significantly, several shear zones active during the late Mesoproterozoic Teapot Orogeny were not reactivated at this time, suggesting that the presence of pre‐existing structures was not the only controlling factor in localizing Palaeozoic deformation. A range of Palaeozoic ages of 440–300 Ma from samples within and external to shear zones points to thermal disturbance from at least the early Silurian through until the late Carboniferous and suggests final cooling and exhumation of the terrane in this interval. The absence of evidence for active deformation and/or new mineral growth in the late stages of the ASO (350–300 Ma) is consistent with a change in orogenic dynamics from thick‐skinned regionally extensive deformation to a more restricted localized high‐geothermal gradient event.
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ItemNo Preview AvailableAge constraints on Oligocene sedimentation in the Torquay Basin, southeastern Australia(TAYLOR & FRANCIS LTD, 2009)
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ItemA transport model study of the breakup of the Antarctic ozone hole in November 2000(American Geophysical Union, 2003)A 3-D off-line transport model is used to examine the breakup of the Antarctic ozone hole in late November and early December 2000. The use of a transport model enables an analysis of the vortex breakup that is not possible from the use of ozonesonde observations alone. By initializing ozone mixing ratio on 1 September 2000, and using parameterized ozone production and loss rates, the evolution of the Antarctic ozone hole is simulated. The model simulation shows that during late November and early December 2000, the Antarctic ozone hole splits into two sections, with low-ozone air subsequently transported over New Zealand and south-eastern Australia. Modeled ozone values agree well with ozonesonde profiles, confirming the role of horizontal transport in the dilution of mid-latitude ozone.
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ItemPrecipitation Simulations Using WRF as a Nested Regional Climate Model(AMER METEOROLOGICAL SOC, 2009-10)Abstract This note examines the sensitivity of simulated U.S. warm-season precipitation in the Weather Research and Forecasting model (WRF), used as a nested regional climate model, to variations in model setup. Numerous options have been tested and a few of the more interesting and unexpected sensitivities are documented here. Specifically, the impacts of changes in convective and land surface parameterizations, nest feedbacks, sea surface temperature, and WRF version on mean precipitation are evaluated in 4-month-long simulations. Running the model over an entire season has brought to light some issues that are not otherwise apparent in shorter, weather forecast–type simulations, emphasizing the need for careful scrutiny of output from any model simulation. After substantial testing, a reasonable model setup was found that produced a definite improvement in the climatological characteristics of precipitation over that from the National Centers for Environmental Prediction–National Center for Atmospheric Research global reanalysis, the dataset used for WRF initial and boundary conditions in this analysis.