Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.14/20506
105 Visitors
124 Hits
0 Downloads
- Title
- Upper crustal structure of the Tamworth Belt, New South Wales : constraints from new gravity data
- Related
- Australian journal of earth sciences, Vol. 54, Issue 8, p.1073-1087
- DOI
- 10.1080/08120090701615725
- Publisher
- Taylor and Francis Ltd
- Date
- 2007
- Author/Creator
- Guo, B
- Author/Creator
- Lackie, M. A
- Author/Creator
- Flood, R. H
- Description
- New gravity data along five profiles across the western side of the southern New England Fold Belt and the adjoining Gunnedah Basin show the Namoi Gravity High over the Tamworth Belt and the Meandarra Gravity Ridge over the Gunnedah Basin. Forward modelling of gravity anomalies, combined with previous geological mapping and a seismic-reflection transect acquired by Geoscience Australia, has led to iterative testing of models of the crustal structure of the southern New England Fold Belt, which indicates that the gravity anomalies can generally be explained using the densities of the presently exposed rock units. The Namoi Gravity High over the Tamworth Belt results from the high density of the rocks of this belt that reflects the mafic volcanic source of the older sedimentary rocks in the Tamworth Belt, the burial metamorphism of the pre-Permian units and the presence of some mafic volcanic units. Modelling shows that the Woolomin Association, present immediately east of the Peel Fault and constituting the most western part of the Tablelands Complex, also has a relatively high density of 2.72 - 2.75 t/m³, and this unit also contributes to the Namoi Gravity High. The Tamworth Belt can be modelled with a configuration where the Tablelands Complex has been thrust over the Tamworth Belt along the Peel Fault that dips steeply to the east. The Tamworth Belt is thrust westward over the Sydney - Gunnedah Basin for 15 - 30 km on the Mooki Fault, which has a shallow dip (∼25°) to the east. The Meandarra Gravity Ridge in the Gunnedah Basin was modelled as a high-density volcanic rock unit with a density contrast of 0.25 t/m³ relative to the underlying rocks of the Lachlan Fold Belt. The modelled volcanic rock unit has a steep western margin, a gently tapering eastern margin and a thickness range of 4.5 - 6 km. These volcanic rocks are assumed to be Lower Permian and to be the western extension of the Permian Werrie Basalts that outcrop on the western edge of the Tamworth Belt and which have been argued to have formed in an extensional basin. Blind granitic plutons are inferred to occur near the Peel Fault along the central and the southern profiles.
- Description
- 15 page(s)
- Subject Keyword
- Crustal structure, gravity modelling, Gunnedah Basin, Mooki Fault, New England Fold Belt, Peel Fault, Tamworth Belt
- Subject Keyword
- crustal structure
- Subject Keyword
- gravity modelling
- Subject Keyword
- Gunnedah Basin
- Subject Keyword
- Mooki Fault
- Subject Keyword
- New England Fold Belt
- Subject Keyword
- Peel Fault
- Subject Keyword
- Tamworth Belt
- Resource Type
- journal article
- Organisation
- Macquarie University. National Key Centre for Geochemical Evolution and Metallogeny of Continents (GEMOC)
- Identifier
- http://hdl.handle.net/1959.14/20506
- Identifier
- ISSN:1440-0952
- Identifier
- mq-rm-2007001064
- Language
- eng
- Reviewed
List Of Titles
