ARC Discovery Grant awarded

In October 2009, the Australian Research Council has announced funding for Discovery Project including JdLCMS-linked researchers Professor Kliti Grice (Curtin) and Dr Paul Greenwood (UWA). The $400,000 project entitled "Linking modern biolipids and pigments to ancient biomolecules using innovative laser and hydro pyrolysis and compound specific stable isotope techniques" will run from 2010-2013.

Project Summary:
Innovative analytical pyrolysis methods in combination with contemporary compound specific molecular and stable isotopic analysis will be used to extend biomarker characterisation in sediments and petroleum. Laser micropyrolysis will be used to access trace hydrocarbons (fluid inclusions; source rock macerals) for improved petroleum-source appraisal. Hydro-pyrolysis will be used to thermally release gas chromatographically resolvable products from extant biolipids to establish new source-biomarker relationships, and evaluate the sedimentary distribution of relevant biomarkers to improve our understanding of petroleum occurrences, palaeoclimates, species evolution and mass extinction events.

Please contact Kliti Grice ( k.grice@curtin.edu.au ) or Paul Greenwood ( pgreenwo@cyllene.uwa.edu.au ) for further information.





Ancient eruptions warn of climate change and mass extinctions

The relationship between catastrophic events, mass extinction and climate change is one of the most exciting topics in Geoscience. For years, a controversy has raged about whether mass extinctions over the last 550 million years were caused by impact of giant asteroids or by huge volcanic eruptions. The asteroid argument was based on evidence for a giant impact around the time of the extinction of the dinosaurs about 65 million years ago. However many major global extinctions also coincide with large volcanic events that each covered an area the size of Western Australia. In a similar way to impacts, volcanic eruptions release large amounts of gas into the atmosphere, such as carbon dioxide, methane and sulphur dioxide, and significantly modify global climate. The key to discriminating between these two arguments is to link the timing of mass extinctions with geological events. F. Jourdan (Research Fellow and manager of 40Ar/39Ar lab at the John de Laeter Centre) and international colleagues are investigating the age and duration of three of Earth’s largest recorded volcanic events (preserved in Australia, South Africa and around the Atlantic Ocean) that seem to have a similar timing to mass extinctions. They have precisely determined the age of these eruptions by 40Ar/39Ar dating, i.e. by measuring the amount of argon accumulated in tiny volcanic crystals over time due to the radioactive decay of potassium. By analysing these crystals from different levels of the volcanic eruption they have estimated the duration and rate of volcanic activity. Their results show that volcanism in the Australian and Circum-Atlantic provinces was limited to a period of 1 or 2 million years and directly synchronous with a major mass extinction, implying that volcanic gases had strongly affected the climate and life. Although the South African eruption produced a similar volume of volcanic rock and released a similar volume of gas, we have shown that that this eruption was spread over 4 million years and did not correspond to a time of major mass extinction.  This suggests that that most species can withstand climatic changes produced by volcanic eruptions provided they have time to adapt. It also shows that the severity of an extinction event depends on the speed with which volcanic gases are released into the atmosphere, rather than the total volume of gas released.  This provides a new picture of Earth’s ability to cope with extreme climate variation, addresses a major geological controversy and provides insights into modern climate change and its effect on biological diversity.

 

 

Do fossil tracks in ancient sediments reflect animal activity?

Modern trails produced by cm-sized, globular amoebas on the sea floor off the Bahamas coast (Matz et al., 2008: Current Biology, 18, 1849) may provide clues about the origin of some Precambrian fossil traces, including the controversially old Stirling Range trails in Western Australia. Curtin geologist Birger Rasmussen and Swedish colleague Stefan Bengtson speculate that the ability of modern giant amoebas to generate trails, which are uncannily similar to those discovered in the ca. 2 billion-year-old Stirling Ranges, raises the possibility that such trails do not necessarily indicate the presence of animals (Science 2009, vol. 323, 346-7 "New and ancient trace makers"). The latter point has been hotly debated since Rasmussen and colleagues established the age of the rocks hosting the Stirling Range trace fossils using the John de Laeter Centre SHRIMP facilities (Science, 2002: vol. 296, 1112-1115; Precambrian Research, 2004: vol. 133, 329-337), but left open the question about what made the trails.

 

New in situ carbon isotope data from pyrobitumen (thermally altered petroleum) in ca. 2.7 billion year old shales, published recently in Nature by a team lead by Curtin researcher Birger Rasmussen, questions evidence for oxygenic photosynthesis at the time of shale deposition.

Nature 455, 1101-1104 (2008)

Tiny residues of solidified oil within ca. 2.7 billion-year-old shales from the Pilbara Craton in Western Australia were analysed with the Cameca nanoSIMS ion probe to test whether hydrocarbon biomarkers characteristic of eukaryotes and cyanobacteria were indigenous to the shales. They found that the C-isotopic composition of the indigenous oil, which was trapped as minute droplets and residues in the shale matrix, was similar to its organic source material but vastly different to the composition of the hydrocarbon biomarkers that had been extracted from the same rocks using organic solvents. This was surprising because the C-isotopic composition of oil is typically similar to its organic source. The new results suggest that the biomarkers were probably not indigenous to the shales, and therefore, they do not provide evidence for the appearance of eukaryotes and cyanobacteria 2.7 billion years ago.

 

The JdLC has recently established a Fission Track (FT) capability to compliment the noble gas thermochronology facilities (i.e. U-Th/He and Argon).

The new FT facility is operated by Dr Martin Danisik (m.danisik@curtin.edu.au) who is seeking interest from postgraduate and postdoctoral researchers for projects which utilize the FT facilities within the thermochronology suite of facilities at JdeLC.