Abstract

A reworking episode is indicated by occurrences of upper Cretaceous coccoliths among middle Eocene assemblages in four basins (Carnarvon, Perth, Eucla, and Otway Basins) along the Australian western and southern margins. The episode falls within the coccolith biostratigraphic interval from the lowest occurrence of Cyclicargolithus reticulatus to the highest occurrence of Daktylethra punctulata, which correlates with the foraminiferal zonal interval P.12-P,13. At the time of the episode (about 45-44 Ma) the sea advanced along the southern margin from the west, causing a transgression in the Eucla Basin and an ingression in the Otway Basin. Coincident with this sea-level rise, and probably the cause of it, was a major acceleration in the spreading rate south of Australia. In the absence of known in-situ occurrences of upper Cretaceous coccoliths on the southern margin or offshore to the south, the Naturaliste Plateau is thought to have been the most likely provenance for the reworked taxa in the Eocene of the Eucla and Otway Basins - short-lived strong currents stripped off coccolith-rich upper Cretaceous sediments on the plateau and transported them eastward. In the Perth Basin a local source, the upper Cretaceous coccolith-rich Gingin Chalk/ Lancelin Beds, is suggested for the reworked taxa, whereas in the Carnarvon Basin a distant source is more likely.
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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)

1984-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

81198 Product http://www.ga.gov.au/metadata-gateway/metadata/record/81198/

Keywords

GA Publication
Journal
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Lineage

Unknown

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

Source Description

Source data not available.

Metadata File Identifier

fae9173a-708b-71e4-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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