Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia

© 2016 Geological Society of America.The Albany-Fraser orogen of Western Australia exhibits a distinct 45° primary (preorogenic) curvature. Consequently, northwest-southeast compression during Mesoproterozoic orogeny was orthogonal to orogenic strike in the east of the orogen, but was oblique in the...

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Main Authors:	Scibiorski, E., Tohver, E., Jourdan, Fred, Kirkland, Chris, Spaggiari, C.
Format:	Journal Article
Published:	Geological Society of America 2016
Online Access:	http://hdl.handle.net/20.500.11937/3073

id	curtin-20.500.11937-3073
recordtype	eprints
spelling	curtin-20.500.11937-30732017-09-13T14:31:36Z Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia Scibiorski, E. Tohver, E. Jourdan, Fred Kirkland, Chris Spaggiari, C. © 2016 Geological Society of America.The Albany-Fraser orogen of Western Australia exhibits a distinct 45° primary (preorogenic) curvature. Consequently, northwest-southeast compression during Mesoproterozoic orogeny was orthogonal to orogenic strike in the east of the orogen, but was oblique in the west. This produced different structural settings in the east and west of the orogen, with a greater component of dextral transpression in the west. We report new 40Ar/39Ar thermochronology from the east Albany-Fraser orogen, and compare these results to the cooling history of the west to examine how cooling varies between the differently striking domains of a curved orogen. The 40Ar/39Ar analyses of hornblende, muscovite, and biotite grains encompass a range of metaigneous and metasedimentary lithologies from two lithotectonic domains. The eastern Biranup Zone yields five hornblende cooling ages at ca. 1190 Ma and seven muscovite and biotite cooling ages between ca. 1171 and 1158 Ma. Hornblende and biotite in the southwestern Fraser Zone record cooling between ca. 1217 and 1205 Ma, and the central Fraser Zone reached 40Ar/39Ar biotite closure temperature at ca. 1157 Ma. Slow 8.2-9.5 °C/m.y. cooling in the eastern Biranup Zone commenced 20 m.y. earlier than 22-33 °C/m.y. cooling in the west Albany-Fraser orogen. The differences in cooling rate are a result of the different structural settings in the east and west. However, similar mica 40Ar/39Ar cooling ages in the east and west record a convergence in cooling history. This suggests that exhumation had become increasingly decoupled from compressional tectonics, instead driven by more passive processes related to isostatic rebound and erosion. 2016 Journal Article http://hdl.handle.net/20.500.11937/3073 10.1130/L561.1 Geological Society of America restricted
repository_type	Digital Repository
institution_category	Local University
institution	Curtin University Malaysia
building	Curtin Institutional Repository
collection	Online Access
description	© 2016 Geological Society of America.The Albany-Fraser orogen of Western Australia exhibits a distinct 45° primary (preorogenic) curvature. Consequently, northwest-southeast compression during Mesoproterozoic orogeny was orthogonal to orogenic strike in the east of the orogen, but was oblique in the west. This produced different structural settings in the east and west of the orogen, with a greater component of dextral transpression in the west. We report new 40Ar/39Ar thermochronology from the east Albany-Fraser orogen, and compare these results to the cooling history of the west to examine how cooling varies between the differently striking domains of a curved orogen. The 40Ar/39Ar analyses of hornblende, muscovite, and biotite grains encompass a range of metaigneous and metasedimentary lithologies from two lithotectonic domains. The eastern Biranup Zone yields five hornblende cooling ages at ca. 1190 Ma and seven muscovite and biotite cooling ages between ca. 1171 and 1158 Ma. Hornblende and biotite in the southwestern Fraser Zone record cooling between ca. 1217 and 1205 Ma, and the central Fraser Zone reached 40Ar/39Ar biotite closure temperature at ca. 1157 Ma. Slow 8.2-9.5 °C/m.y. cooling in the eastern Biranup Zone commenced 20 m.y. earlier than 22-33 °C/m.y. cooling in the west Albany-Fraser orogen. The differences in cooling rate are a result of the different structural settings in the east and west. However, similar mica 40Ar/39Ar cooling ages in the east and west record a convergence in cooling history. This suggests that exhumation had become increasingly decoupled from compressional tectonics, instead driven by more passive processes related to isostatic rebound and erosion.
format	Journal Article
author	Scibiorski, E. Tohver, E. Jourdan, Fred Kirkland, Chris Spaggiari, C.
spellingShingle	Scibiorski, E. Tohver, E. Jourdan, Fred Kirkland, Chris Spaggiari, C. Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
author_facet	Scibiorski, E. Tohver, E. Jourdan, Fred Kirkland, Chris Spaggiari, C.
author_sort	Scibiorski, E.
title	Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
title_short	Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
title_full	Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
title_fullStr	Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
title_full_unstemmed	Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia
title_sort	cooling and exhumation along the curved albany-fraser orogen, western australia
publisher	Geological Society of America
publishDate	2016
url	http://hdl.handle.net/20.500.11937/3073
first_indexed	2018-09-06T17:39:37Z
last_indexed	2018-09-06T17:39:37Z
_version_	1610880728462000128

Cooling and exhumation along the curved Albany-Fraser orogen, Western Australia

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