CAOG - PhD Student

Mrs Amy Bowater

Stable carbon isotope compositions and distributions of age-diagnostic molecular fossils in Indonesian oils and source rocks for oil-source correlation

As life evolved over geological time, new organisms evolved and other organisms became extinct. As a consequence the biomarkers that are associated with these new or extinct organisms can be age specific, if they are known to have a single source. The presence of such biomarkers in sediments and oils can provide information such as a minimum age, in the case of an extinct species or a maximum age, in the case of an evolved species. The presence of angiosperm biomarkers for example limit the maximum age of sedimentary organic matter to the Cretaceous (e.g. Simoneit, 1998; Moldowan et al., 1994).

Carbon isotopes can be used to distinguish differences in the age of organic matter. This can be done using the known variation in the isotopic signature of atmospheric carbon dioxide over geological time (e.g. Andrusevich et al., 1998). The presence of a particular biomarker that is specific to only one organism in different samples that yield compatible stable carbon isotope ratios is a good indication that the organic matter was deposited at a similar time.

To enable accurate compound specific isotope analysis (CSIA) of these types of compounds it is necessary to isolate them from other components in a significant quantity, which is often a complicated task. Therefore, an important aspect of the project will be to improve existing separation techniques and to develop novel liquid chromatography, novel molecular sieve procedures and Gas-chromatography- gas chromatography methods to enrich and isolate the higher plant biomarkers of interest.

Supervisors

Professor Kliti Grice, Professor Robert Alexander

Associate supervisors

Dr Ben van Aarssen (Chevron), Dr Joseph Curiale

Funding

ARC (Linkage) APAI, WAERA scholarship