Abstract

The southern margin of Australia, formed by the separation of Australia and Antarctica in theCretaceous, has long been considered an example of a classic, non-volcanic, passive, rifted margin. In recent times it has been cited as an excellent example of a 'lower plate' margin inthe terminology of detachment models of passive margin formation. As the margin has been relatively sediment-starved since breakup, and particularly in the Tertiary, it represents anexcellent opportunity to test detachment models via reflection seismic data and drilling. In this document, we propose that a total of seven holes be drilled by the Ocean DrillingProgram in the central Great Australian Bight (GAB). Five of these holes are located close tothe previously interpreted continent-ocean boundary (COB), which high-quality seismic datasuggest may actually be a metamorphic core complex. The holes have the following basic aims: 1.Test the applicability of detachment tectonics to passive margin formation by drillingthrough a master detachment to extended lower continental crust; 2.Sample acoustic basement at several sites to characterise the tectonic and magmaticprocesses that have been influential at high rates of continental extension and/or duringearly and slow oceanic spreading. In the event that the interpretation of a metamorphic core complex proves to be incorrect and oceanic crust is encountered, then two additional holes are proposed to: 1.Date the oldest sediments above oceanic crust in the South Australian Abyssal Plain, andhence constrain the currently ill-defined age of onset of spreading between Australia andAntarctica and refme the breakup history of eastern Gondwanaland. 2.Date and characterise the extensional listric faulting that is prominent in possible oceaniccrust on the South Australian Abyssal Plain. As the data on which these sites are proposed is sparse and, in some cases, old, the AustralianGeological Survey Organisation (AGSO) proposes to carry out a deep-seismic program in thecentral GAB that will allow a refmal interpretation and consequent up-grading or modificationof the proposed sites in 1995/96.
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Product Type/Sub Type

nonGeographicDataset

Constraints

Creative Commons Attribution 4.0 International Licence

IP Owner

Commonwealth of Australia (Geoscience Australia)

Author(s)

Date (publication)

1995-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

14802 Product http://www.ga.gov.au/metadata-gateway/metadata/record/14802/

Keywords

GA Publication
Record
structural geology
marine survey
marine
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Digital Transfer Options

onLine

Distributor

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

Metadata File Identifier

a05f7892-7431-7506-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 SECURITY CLASSIFICATION

unclassified

Metadata Contact

Role
pointOfContact
Organisation Name
Commonwealth of Australia (Geoscience Australia)
City
Canberra
Administrative Area
ACT
Postal Code
2601
Country
Australia
Email Address
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