MACROCYCLIC ALKANES: MARKERS FOR THE FRESHWATER ALGA BOTRYOCOCCUS BRAUNII IN THE GIPPSLAND BASIN

Abstract

Macrocyclic alkanes are novel markers derived from the algaenan of Botryococcus braunii (B. braunii) independent of the race of B. braunii. Analysis of a crude oil (Leatherjacket–1, Cretaceous) and a sediment from the Gippsland Basin (Flounder–1 well, Cretaceous) reveal the presence of macrocyclic alkanes, suggesting an input to the organic matter from freshwater alga B. braunii. This is the first report of macrocyclic alkanes in Australian crude oils and in sediments other than torbanites. These compounds are important because they ultimately derive from the algaenan of B. braunii and are thus selectively preserved in crude oils unlike other B. braunii biomarkers that are not always preserved.