Structure and kinematics of the Louth-Eumarra Shear Zone (north-central New South Wales, Australia) and implications for the Paleozoic plate tectonic evolution of eastern Australia

Dunstan, S., Rosenbaum, G. and Babaahmadi, A. (2016) Structure and kinematics of the Louth-Eumarra Shear Zone (north-central New South Wales, Australia) and implications for the Paleozoic plate tectonic evolution of eastern Australia. Australian Journal of Earth Sciences, 63 1: 1-18. doi:10.1080/08120099.2016.1131195


Author Dunstan, S.
Rosenbaum, G.
Babaahmadi, A.
Title Structure and kinematics of the Louth-Eumarra Shear Zone (north-central New South Wales, Australia) and implications for the Paleozoic plate tectonic evolution of eastern Australia
Journal name Australian Journal of Earth Sciences   Check publisher's open access policy
ISSN 0812-0099
1440-0952
Publication date 2016-02-05
Sub-type Article (original research)
DOI 10.1080/08120099.2016.1131195
Open Access Status Not Open Access
Volume 63
Issue 1
Start page 1
End page 18
Total pages 18
Place of publication Abingdon, Oxfordshire, United Kingdom
Publisher Taylor & Francis
Collection year 2017
Language eng
Abstract The ∼E–W-trending Olepoloko Fault and ∼ENE-trending Louth-Eumarra Shear Zone in north-central New South Wales are approximately orthogonal to the dominant ∼N–S-trending structural grain of Paleozoic eastern Australia. These structures have been interpreted to represent the boundary between the Thomson and Lachlan orogens, but their exact geometry and kinematics remain unclear owing to the scarcity of surface exposure. Using gridded aeromagnetic data and limited field mapping, we obtained new data on the tectonic history of the Louth-Eumarra Shear Zone, which seems to represent a broad zone of dextral shearing with a component of crustal thickening indicated by the recognition of kyanite growth in a mica-schist. The timing of deformation is relatively poorly constrained, but at least a component of the dextral shearing appears to be coeval or younger than the age of displaced late Silurian and Early Devonian granitoids. Additional indicators for dextral kinematics farther north, along the ∼ENE-trending Culgoa Fault, suggest that the width of the zone that was subjected to dextral deformation is possibly >100 km. This raises the possibility that a large component of dextral displacement was accommodated in this region. In a broader geodynamic context, we discuss the possibility that the precursor of the Louth-Eumarra Shear Zone and Olepoloko Fault originated from segmentation between the northern and southern Tasmanides, perhaps during the Cambrian. The existence of such a discontinuity may have buttressed the process of oroclinal bending in the Silurian. The observed dextral kinematics has possibly resulted from reactivated deformation during the Tabberabberan and Alice Springs orogenies.
Keyword Louth-Eumarra Shear Zone
Olepoloko Fault
Lachlan Orogen
Southern Thomson Orogen
Dextral kinematics
Girilambone Group
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
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Created: Fri, 05 Feb 2016, 22:44:52 EST by Dr Gideon Rosenbaum on behalf of School of Earth Sciences