Year
2011
Degree Name
Bachelor of Science (Honours)
ANZSRC / FoR Code
040301 Basin Analysis, 040307 Ore Deposit Petrology, 040313 Tectonics
Department
School of Earth & Environmental Sciences
Recommended Citation
Carter, Lewis, Tectonic Control of Cenozoic Deposition in the Cumberland Basin, Penrith/Hawkesbury Region, New South Wales, Bachelor of Science (Honours), School of Earth & Environmental Sciences, University of Wollongong, 2011.
http://ro.uow.edu.au/thsci/3
Abstract
The Lapstone Structural Complex and the Hornsby Warp are prominent features of the Sydney Basin, representing the greatest zone of deformation. Despite this, the structure and the timing of uplift for the Complex as well as its subsequent effects on Cenozoic deposition are still debated. Recently reprocessed seismic lines shot in the area have forced a re-evaluation of the geological history, with the current paradigm focusing on an earlier timing of uplift in the Paleogene/Neogene Periods. Units of critical importance were the Rickabys Creek Gravel and the Londonderry Clay, where it was found through fieldwork that both units outcrop on the topographically impressive Lapstone Monocline as well as the low-lying Cumberland Plains. The projects aims were to examine the distribution of these Paleogene/Neogene units, with the hope that they would be influenced by the surrounding tectonic features. The geometry of the Rickabys Creek Gravel clearly showed thinning to the north, which was attributed to the development of a basin in the underlying Triassic strata. Outcrops of Londonderry Clay implied two periods of uplift for the region – the uplift of the Hornsby Warp, followed by the uplift of the Lapstone Structural Complex. Palaeomagnetic dating of the Londonderry Clay was attempted, in order to quantify the timing of uplift however, it was unsuccessful. Continuing work in the region will hopefully provide a firmer knowledge of the evolution of the area.