Abstract

Basement architecture off western Tasmania is a legacy of late Neoproterozoic-Cambrian subduction-related processes, ocean basin closure and multiple accretionary events, culminating in formation of the Delamerian-Ross and western Lachlan orogens. Structures associated with these fold belts were subsequently reactivated during late Mesozoic-Cenozoic Gondwana breakup and the separation of Australia from Antarctica, strongly influencing the pattern and geometry of offshore rifting, including formation of an ocean-continent transform boundary off western Tasmania. Seismic reflection profiles combined with recently acquired high resolution aeromagnetic data permit this boundary and its associated reactivated basement structures (Avoca-Sorell fault system) to be mapped in greater detail than has hitherto been possible and point to a transform margin dominated by steeply outward-dipping structures and deep sedimentary basins similar to other transform margin ocean-continent boundaries, including the highly prospective Côte d'Ivore-Ghana region off the west African coast. Basement highs and rotated pre-rift crustal blocks adjacent to the west Tasmanian transform margin incorporate significant volumes of granite as well as a lower crust of probable Mesoproterozoic age that is locally juxtaposed against lower Paleozoic sequences intruded and/or floored by basaltic and ultramafic material. Aeromagnetic anomalies sourced from these basement rocks change orientation from NW- to NE-trending across the Avoca-Sorell fault system and can be traced laterally into regions of known onshore basement geology, highlighting both the tectonic significance of this structure and its origins during lower Paleozoic deformation accompanying the Delamerian-Ross orogeny.
Google map showing geographic bounding box with values North bound East bound West bound South bound
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Product Type/Sub Type

nonGeographicDataset - GA Publication - Abstract

Constraints

license
Creative Commons Attribution 3.0 Australia Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

2010

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

Keywords

GA Publication
Abstract
plate tectonics
sedimentary basins
petroleum exploration
continental margins
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Lineage

Unknown

Digital Transfer Options

onLine

Distributor

Role
distributor
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address

Metadata File Identifier

a05f7892-f6f1-7506-e044-00144fdd4fa6

Metadata Standard Name

ANZLIC Metadata Profile: An Australian/New Zealand Profile of AS/NZS ISO 19115:2005, Geographic information - Metadata

Metadata Standard Version

1.1

Metadata Date Stamp

2010-03-31

METADATA SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Geoscience Australia
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
Related Links
For information on acquiring this product,
please contact the Geoscience Australia Sales Centre via:

fax:
+61 2 6249 9960; or
phone:
1800 800 173 (within Australia);
 
+61 2 6249 9966 (outside Australia).

Please note that support hours are 9 am to 5 pm weekdays