Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin
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. Str...
| Main Authors: | , , |
|---|---|
| Format: | Journal Article |
| Published: |
Taylor & Francis Co Ltd
2014
|
| Subjects: | |
| Online Access: | http://hdl.handle.net/20.500.11937/32099 |
| _version_ | 1848753567961186304 |
|---|---|
| author | Och. D. Offler, R. Zwingmann, Horst |
| author_facet | Och. D. Offler, R. Zwingmann, Horst |
| author_sort | Och. D. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | 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. |
| first_indexed | 2025-11-14T08:26:35Z |
| format | Journal Article |
| id | curtin-20.500.11937-32099 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:26:35Z |
| publishDate | 2014 |
| publisher | Taylor & Francis Co Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-320992017-09-13T15:17:39Z Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin Och. D. Offler, R. Zwingmann, Horst - joints - Sydney–Hunter region - eastern Australia - dykes - faults - gouge K–Ar dating 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. 2014 Journal Article http://hdl.handle.net/20.500.11937/32099 10.1080/08120099.2014.906503 Taylor & Francis Co Ltd restricted |
| spellingShingle | - joints - Sydney–Hunter region - eastern Australia - dykes - faults - gouge K–Ar dating Och. D. Offler, R. Zwingmann, Horst Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title | Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title_full | Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title_fullStr | Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title_full_unstemmed | Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title_short | Constraining timing of brittle deformation and fault gouge formation in the Sydney Basin |
| title_sort | constraining timing of brittle deformation and fault gouge formation in the sydney basin |
| topic | - joints - Sydney–Hunter region - eastern Australia - dykes - faults - gouge K–Ar dating |
| url | http://hdl.handle.net/20.500.11937/32099 |