Traces from the past: the Cenozoic regolith and intraplate neotectonic history of the Gun Emplacement, a ferricreted bench on the western margin of the Mt Lofty Ranges, South Australia

The Gun Emplacement is a small but distinctive bench on the Eden-Burnside Fault Escarpment near Anstey Hill, in the northeastern suburbs of Adelaide, South Australia, occurring at an elevation of ∼210-220 m asl. It is underlain by Middle Eocene North Maslin Sand and is capped by resistant, ferricret...

Full description

Saved in:
Bibliographic Details
Published in:Australian journal of earth sciences 2010-07, Vol.57 (5), p.577-595
Main Authors: Bourman, R. P., Buckman, S., Pillans, B., Williams, M. A. J., Williams, F.
Format: Article
Language:English
Subjects:
Age
Benches
Capping
Cenozoic
Elevation
Escarpments
Faults
ferricrete
intraplate deformation
Mt Lofty Ranges
neotectonics
paleochannel deposits
paleomagnetic dating
Sand
Surface chemistry
weathering
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The Gun Emplacement is a small but distinctive bench on the Eden-Burnside Fault Escarpment near Anstey Hill, in the northeastern suburbs of Adelaide, South Australia, occurring at an elevation of ∼210-220 m asl. It is underlain by Middle Eocene North Maslin Sand and is capped by resistant, ferricreted colluvium. Paleomagnetic dating of hematitic mottles in the ferricreted colluvium, immediately underlying the emplacement, returned a Pliocene/Early Pleistocene age. This age is equivalent to that obtained for summit surface weathering. Fault scarps and exposures, including slickensides and fault gouge material, suggest that the Eden-Burnside Fault at this location has a strong en échelon pattern developed in response to reverse-sinistral oblique-slip faulting, reflecting continental stress fields. Remnants of ferricrete cappings forming stranded benches on the Eden-Burnside Fault Escarpment at elevations up to 25 m above the Gun Emplacement demonstrate recurrent tectonism of the South Mt Lofty Ranges related to intraplate deformation. There are at least four distinct ferricrete benches preserved on the eastern side of the active fault leading up from the Gun Emplacement surface. These benches demonstrate alternating periods of stability and tectonic activity disrupting and uplifting the ferricreted surfaces. A fresh surface rupture occurs and may be related to a recent seismic event.
ISSN:0812-0099
1440-0952
DOI:10.1080/08120099.2010.494764