Basement Constraints on Offshore Basin Architechture as Determined by new Aeromagnetic Data Acquired over Bass Strait and Western Margin of Tasmania  

Authors / CoAuthors

Morse, M.P. | Gibson, G. | Mitchell, C.

Abstract

In early 2008 Geoscience Australia and Mineral Resources Tasmania acquired 141,234 km of high resolution (800m line spacing) aeromagnetic data over Bass Strait and the offshore marginal basins of western Tasmania. The data fill a gap in the existing aeromagnetic coverage between Tasmania and mainland Australia and provide fresh insights into basement structure and its control on basin architecture and sedimentation patterns during Gondwanan continental break-up and the separation of Australia from Antarctica. Prominent in the new data are several northwest-trending basement faults that extend from the mainland into westernmost Tasmania and the South Tasman Rise; they appear to represent an offshore extension of previously mapped structures in western Victoria (Hummocks and Yarramyljup Faults). These structures postdate, truncate and offset in a sinistral sense many older north- and northeast-trending basement structures, including the late Neoproterozoic Arthur lineament in Tasmania, the Bambra fault in central Victoria and the boundary between the Lachlan and Delamerian Orogens (Moyston Thrust) in western Victoria. The Hummocks Fault coincides with a narrow belt of ultramafic rocks and possibly continues offshore as a series of prominent magnetic anomalies whereas the Yarramyljup Fault may form the western limit of Proterozoic (Tyennan) basement in Tasmania. The distribution and geometry of Mesozoic-Tertiary offshore sedimentary basins in western Tasmania and the South Tasman Rise is consistent with reactivation of the older basement structures in a north-south-directed transtensional tectonic regime. Magmatic rocks intruded into the Bass, Otway and Sorell Basins and Torquay Sub-Basin are clearly delineated in the new aeromagnetic data.

Product Type

nonGeographicDataset

eCat Id

65861

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Keywords

• External PublicationConference Paper

( Theme )

• geophysics

( Theme )

• continental margins

( Theme )

• petroleum exploration

( Theme )

• marine

• AU-SAAU-TASAU-VIC

Australian and New Zealand Standard Research Classification (ANZSRC)

• Earth Sciences

• Published_Internal

Publication Date

2009-01-01T00:00:00

Creation Date

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

Access - restricted

Use - license

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Purpose

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unknown

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geoscientificInformation

Series Information

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Unknown

Parent Information

Extents

[-50.0, -28.0, 138.0, 152.0]

Reference System

Spatial Resolution

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