File(s) under permanent embargo
Soft-sediment deformation structures in the middle permian Wandrawandian siltstone, southern Sydney basin: implications for depositional environment and basin tectonics
The Middle Permian Wandrawandian Siltstone at Warden Head near Ulladulla in the southern Sydney Basin is dominated by fossiliferous siltstone and mudstone, with a large amount of dropstones (lonestones) and some pebbly sandstone beds. Two general types of deposits are recognised from the cliff succession in view of the timing and mechanism of their formation. One is represented by the background (or primary) deposits of offshore to slope environments with abundant dropstones of glacial marine origin. This facies occurs throughout the cliff sections at Warden Head. The second type is distinguished by secondary, soft-sediment deformational deposits and structures of the primary (background) deposits, and comprises three successive layers of sandy mudstone dikes. In the second type of deposit, metre scale, laterally extensive syn-depositional slump deformation structures occur extensively in the middle part of the Wandrawandian Siltstone. The deformation structures vary in morphology and pattern, including large-scale complex-type folds, flexural stratification, concave-up structures, small-magnitude -faults accompanied by folding and brecciation. The slumps and associated syn-depositional structures are herein attributed to penecontemporaneous deformations of soft sediments (mostly mud and silty mud), formed as a result of mass movement of unconsolidated and/or semi-consolidated substrate following earthquake events. The occurrence of the earthquake event deposits (or seismites) at Warden Head supports the current view that the Sydney Basin was located in a back-arc setting near the New England magmatic arc on an active continental margin during the Middle Permian, and the timing of the earthquake events is here interpreted to indicate the onset of the Hunter Bowen Orogeny in the southern Sydney Basin.
History
Title of proceedings
Proceedings of the thirty fifth Symposium on Advances in the study of the Sydney Basin, September 29-30, 2003, Wollongong NSWEvent
Advances in the study of the Sydney Basin. Symposium (35th : 2003 : Wollongong, N.S.W.)Pagination
307 - 314Publisher
School of Geosciences, University of WollongongLocation
Wollongong, N.S.W.Place of publication
Wollongong, N.S.W.Start date
2003-09-29End date
2003-09-30Language
engPublication classification
E1 Full written paper - refereedCopyright notice
2003, School of Geosciences, University of WollongongEditor/Contributor(s)
A Hutton, B Jones, P Carr, B Ackerman, A SwitzerUsage metrics
Categories
No categories selectedKeywords
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC