The Structural Geology of the Yohoe Creek to Cape Jervis Area, Fleurieu Peninsula,
South Australia.
Andrew Macdonald B.Sc
Thesis submitted as partial fulfilment of the requirements for the Honours Degree of Bachelor of Science
November 1995
THE UNIVERSITY OF ADELAIDE Department of Geology and Geophysics
NATIONAL GRID REFERENCE:
Jervis 1: 100 000 sheet
ABSTRACT
The Neoproterozoic and Cambrian Umberatana, Wilpena, Normanville and Kanmantoo Group rocks of the Y ohoe Creek to Cape Jervis area underwent compressional deformation during the Cambra-Ordovician Delamerian Orogeny. This deformation prevailed as thrust faulting, and folding. In some cases the thrusts were accommodated by slip along reactivated Cambrian basin extension faults. Structural mapping of the area shows that the main structure of the area is that of two thrust faults, which are both associated with folding. Folds in the area tend to be of similar (type 2) style and manifest themselves by slip along cleavage planes. An imbricate fan in the southern part of the area is of the leading imbricate fan type. A balanced cross section through the area was based on fold analysis and measurements taken during field work, this section was then restored giving a shortening of 53% for the area. Three dimensional analysis of the structure of the area by Vulcan TM software resulted in a more easily visualised picture of the shape and extent of the folds in the area as well as showing the depth relationships of the thrusts. The method used here of tying together cross sections is a promising method for further work involving the SAFTB.
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