Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/33302

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Title
K-Ar dating of fault gouge in the northern Sydney Basin, NSW, Australia-implications for the breakup of Gondwana
Author/Creator
Zwingmann, H.;  Offler, R.;  Wilson, T.;  Cox, S. F.
Institution
The University of Newcastle. Faculty of Science & Information Technology, School of Environmental and Life Science
Description
The occurrence of synkinematic and authigenic clay minerals is a common feature in fault gouges. Few attempts have been made to date fault gouges. We present the first age data in Australia for synkinematic illite–smectite growth in two fault zones of the northern Sydney Basin, NSW. The faults occur at Burwood Beach, NSW in the northern part of the Sydney Basin and are hosted by Early Permian siltstones, tuffs and coals of the Lambton Formation, Newcastle Coal Measures. The faults are 1.5 m apart, show normal displacement and trend N–S with steep easterly dips. Foliated gouge zones, comminution and dilational breccias are developed along both fault surfaces. K–Ar ages extracted from samples in the gouge and tuffs in the damage zones are 172 (6–10 μm) to 119 Ma (<0.4 μm), respectively. Older ages of 272–281 Ma for the coarse fractions (>2 μm), 237–245 Ma for the <2 μm fraction, 218 Ma for the <0.4 μm fraction and 196 Ma for the <0.1 μm fraction have been obtained from siltstones within and outside the damage zone. We believe the younger ages of 196–237 Ma indicate the time at which diagenetic illite–smectite formed and the 122–150 Ma dates from the <2 μm fraction represent the maximum age of gouge formation. The younger ages are thought to reflect the last slip event occurring on the faults, which is related to the rifting and dispersal of the eastern margin of the Australian continent.
Relation
Journal of Structural Geology Vol. 26, Issue 12, p. 2285-2295
Publisher Link
http://dx.doi.org/10.1016/j.jsg.2004.03.007
Date
2004
Publisher
Elsevier Ltd.
Keyword(s)
gouge;  K–Ar dating;  Sydney Basin;  Australia
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/33302
Identifier
ISSN:0191-8141
Reviewed
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Subject
"Journal of Structural Geology"
 
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