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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

Journal Article


Abstract


  • 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 similar to 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 echelon 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.

Authors


  •   Bourman, Bob P.
  •   Buckman, Solomon
  •   Pillans, Brad (external author)
  •   Williams, Martin AJ. (external author)
  •   Williams, Frances (external author)

Publication Date


  • 2010

Citation


  • Bourman, R. P., Buckman, S., Pillans, B., Williams, M. AJ. & Williams, F. (2010). 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. Australian Journal of Earth Sciences, 57 (5), 577-595.

Scopus Eid


  • 2-s2.0-77954319419

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5070

Has Global Citation Frequency


Number Of Pages


  • 18

Start Page


  • 577

End Page


  • 595

Volume


  • 57

Issue


  • 5

Abstract


  • 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 similar to 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 echelon 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.

Authors


  •   Bourman, Bob P.
  •   Buckman, Solomon
  •   Pillans, Brad (external author)
  •   Williams, Martin AJ. (external author)
  •   Williams, Frances (external author)

Publication Date


  • 2010

Citation


  • Bourman, R. P., Buckman, S., Pillans, B., Williams, M. AJ. & Williams, F. (2010). 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. Australian Journal of Earth Sciences, 57 (5), 577-595.

Scopus Eid


  • 2-s2.0-77954319419

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/5070

Has Global Citation Frequency


Number Of Pages


  • 18

Start Page


  • 577

End Page


  • 595

Volume


  • 57

Issue


  • 5