Hostname: page-component-89b8bd64d-dvtzq Total loading time: 0 Render date: 2026-05-09T04:54:38.281Z Has data issue: false hasContentIssue false

Further evidence for two metamorphic events in the Mawson Continent

Published online by Cambridge University Press:  04 December 2017

Megan A. Williams*
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
David E. Kelsey
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
Martin Hand
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
Tom Raimondo
Affiliation:
School of Natural and Built Environments, University of South Australia, Adelaide, SA 5001, Australia
Laura J. Morrissey
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia School of Natural and Built Environments, University of South Australia, Adelaide, SA 5001, Australia
Naomi M. Tucker
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
Rian A. Dutch
Affiliation:
Department of Earth Sciences, School of Physical Sciences, University of Adelaide, Adelaide, SA 5005, Australia Geological Survey of South Australia, Department of State Development, Level 7, 101 Grenfell Street, Adelaide, SA 5000, Australia

Abstract

In this study, in situ and erratic samples from George V Coast (East Antarctica) and southern Eyre Peninsula (Australia) have been used to characterize the microstructural, pressure–temperature and geochronological record of upper amphibolite and granulite facies polymetamorphism in the Mawson Continent to provide insight into the spatial distribution of reworking and the subice geology of the Mawson Continent. Monazite U-Pb data shows that in situ samples from the George V Coast record exclusively 2450–2400 Ma ages, whereas most erratic samples from glacial moraines at Cape Denison and the Red Banks Charnockite record only 1720–1690 Ma ages, consistent with known ages of the Sleaford and Kimban events, respectively. Phase equilibria forward modelling reveals considerable overlap of the thermal character of these two events. Samples with unimodal 1720–1690 Ma Kimban ages reflect either formation after the Sleaford event or complete metamorphic overprinting. Rocks recording only 2450–2400 Ma ages were unaffected by the younger Kimban event, perhaps as a result of unreactive rock compositions inherited from the Sleaford event. Our results suggest the subice geology of the Mawson Continent is a pre-Sleaford-aged terrane with a cover sequence reworked during the Kimban event.

Information

Type
Earth Sciences
Copyright
© Antarctic Science Ltd 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable

Supplementary material: PDF

Williams et al supplementary material

Williams et al supplementary material 1

Download Williams et al supplementary material(PDF)
PDF 1.2 MB