SCHAEFER, F.1, DZUBER, R.1, MURRAY, T.2, GRIFFITHS, P. A.2, and LEMON, N.3
1Midland Valley Exploration
Ltd, Hannover, Germany
2Midland Valley Exploration
Ltd, Glasgow, UK
3NCPGG, Adelaide, Australia
Abstract: 3D Restoration of the Oratunga Breccia Body, Flinders Range, South Australia: is it a Diapir?
The Oratunga Breccia Body of the Flinders Range, South Australia, has been subject to controversial discussion of its genetic origin, ranging from carbonatitic intrusions and deformed horst blocks to megaslumps and diapirism.
Three-dimensional restoration provides a powerful
tool to validate structural
interpretations and the geohistory of a given
model. We use 3D restoration software to examine a syndepositional diapiric
interpretation of the Oratunga structure. This interpretation is based
on analogue diapir modelling results resembling the field structure around
the Oratunga body.
Based on the assumption that salt flow at depth generates a response in the sedimentary overburden, the sequential restoration of overburden horizons will reproduce salt flow patterns and overburden basin geometry through time.
The 3D model is built from outcrop traces, dip
data, and two structural
cross
sections
through the Oratunga structure.
We carry out a sequential restoration of key horizons surrounding the presumed
diapir, reconstructing eroded strata where necessary. The proposed geohistory
model of a diapiric rise triggered by an early inversion fault is tested
and refined through the restoration results.
AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas