Publication Name: Eastern Australian Basins Symposium 2001
Authors: K.L. Bann and C.R. Fielding
Date Published: November 2001
Number of Pages: 33
Reference Type: Magazine Article
Abstract:
Trace fossils provide a valuable additional sedimentological criterion with which to evaluate the palaeoenvironments of ancient successions. Recent re-evaluation of the sedimentology and stratigraphy of certain Permian formations in the Sydney and Bowen Basins of eastern Australia emphasises the usefulness of trace fossil analysis. This paper provides three examples from that work, with specific reference to their usefulness in hydrocarbon exploration and reservoir description. In the Pebbley Beach Formation of the southern Sydney Basin, trace fossils are used to identify a transgressive surface of erosion separating underlying bay facies from overlying offshore marine deposits, at a sharp-bounded sandstone bed that would otherwise simply be regarded as an event bed. In the German Creek Formation of the central Bowen Basin, a probable sequence boundary is recognised within what was previously regarded as a simple progradational succession. Thirdly, re-evaluation of the Freitag Formation of the Bowen Basin has led to significant refinement of the facies model for the interval and the construction of a detailed sequence stratigraphic model. This latter model identifies parasequence scale cyclicity and a sequence boundary of probable regional extent. The case studies documented illustrate the relevance of incorporating trace fossil studies into facies, stratigraphic and reservoir models for exploration and production of hydrocarbons.