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dc.contributor.authorOch. D.
dc.contributor.authorOffler, R.
dc.contributor.authorZwingmann, Horst
dc.identifier.citationOch. D. and Offler, R. and Zwingmann, H. 2014. Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin. Australian Journal of Earth Sciences. 61 (3): pp. 337-350.

Structural and K–Ar dating studies of gouge in N–S, NNE and E–W-trending faults in four locations in the Sydney–Hunter region are reported. The fault zones are manifest as joint swarms and highly brecciated zones containing gouge with authigenic illite produced as a result of fluid infiltration. Strike-slip movement accompanied by minor dip-slip, normal movement occurred on the NNE faults, with dip slip on N–S and E–W-trending faults. In this study, gouge from a NE-trending, steep, SE-dipping fault showing dip-slip movement at Cut 10, on the Hunter Expressway and from an E–W-trending, steep south-dipping, normal fault at the Westside Open Cut, Lake Macquarie have been analysed. K–Ar dating of illite and illite–smectite in fractions extracted from fault gouges in areas unaffected by a thermal overprint reveals ages varying from 166 to 119 Ma for the <2 μm and finer fractions, and a mean age of ca 120 Ma for the <0.4 μm fraction. In the Sydney area and the Westside Open Cut coal mine, Lake Macquarie, the ages obtained from similar size fractions both for the gouge and for the host rocks are younger (134–76 Ma; av. <0.4 μm = 111 Ma). The data indicate influence of a thermal overprint associated with subsurface magmas emplaced during the early stages of the rifting of eastern Gondwana during the early Cretaceous.

dc.publisherTaylor & Francis Co Ltd
dc.subject- joints
dc.subject- Sydney–Hunter region
dc.subject- eastern Australia
dc.subject- dykes
dc.subject- faults
dc.subject- gouge
dc.subjectK–Ar dating
dc.titleConstraining timing of brittle deformation and fault gouge formation in the Sydney Basin
dc.typeJournal Article
dcterms.source.titleAustralian Journal of Earth Sciences
curtin.departmentDepartment of Applied Geology
curtin.accessStatusFulltext not available

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