K. L. Bann

University of Queensland, Australia

ABSTRACT: Ichnology and High-Resolution Sequence Stratigraphy of the Permian Pebbley Beach Formation, Sydney Basin, Australia

The Early Permian Pebbley Beach Formation of the southern Sydney Basin Australia, is exposed in coastal outcrop and contains a plethora of spectacularly preserved trace fossils, ichnofabrics, transgressive surfaces of erosion, and a complex record of palaeoclimatic and relative sea-level change. A high degree of vertical and lateral variability and the removal of significant thickness of section from the top portions of a number of separate parasequences, by large channel structures, has led to considerable confusion surrounding the interpretation of the depositional history and cyclicity of the sequence. The formation is interpreted as a complex of wave-dominated, progradational, siliciclastic coastal parasequences (at least 6 parasequences are preserved) with environments ranging from lower offshore to storm-dominated shoreface to estuarine. Deposition occurred during thermal basin sag in the embryonic stage of foreland basin formation. A detailed and comprehensive ichnological study has shed new light on the palaeoenvironmental interpretation of the Pebbley Beach Formation and produced a high-resolution sequence stratigraphic model.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado