Abstract

The Early Cretaceous non-marine volcaniclastic Eumeralla Formation accumulated in a rift basin on the southern margin of Australia during the break-up of eastern Gondwana. Wireline-Iog analysis and a range of sedimentary data have helped to discriminate three major basin-wide informal lithostratigraphic units in the formation. From the base of the formation they are: Eumeralla I: siltstone/mudstone/sandstone/coal; Eumeralla II: siltstone/mudstone/thin lithic sandstone; and Eumeralia III: volcaniclastic sandstone. A fourth unit - Eumeralla IV: siltstone/sandstone/coal - occurs throughout the western Otway Basin, but is absent, probably because of erosion, from the central and eastern pans of the basin. The bases of all four lithostratigraphic units are probably diachronous. The succession of lithostratigraphic units Eumeralla I- IV is interpreted as representing coal swamps and flood plains of low-energy streams; shallow and deep freshwater lakes; channel tracts and flood plains of high-energy streams; and channel tracts, flood plains and coal swamps of low- energy streams respectively. Sedimentary facies analysis of outcropping Eumeralla II and Eumeralla III in the eastern Otway Basin confirms the interpretations for these units. The basin-wide extent of the three lower lithostratigraphic units implies that a single integrated drainage system for the entire basin was established at the onset of Eumeralla Formation deposition, and persisted at least until the late Albian. This inference is supported by the close correlation between variations in lithology and depositional environments and the Aptian- Albian sea-level changes. However, intrabasinal volcanism significantly influenced sedimentation and was probably the primary control on basin drainage.
Google map showing geographic bounding box with values North bound -26.0 East bound 153.0 West bound 112.0 South bound -44.0
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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)

1997-01-01T00:00:00

Product Type

nonGeographicDataset

Topic Category

geoscientificInformation

GA Catalogue Number

81471 Product http://www.ga.gov.au/metadata-gateway/metadata/record/81471/

Keywords

GA Publication
Journal
NSW
SA
TAS
WA
VIC
Earth Sciences

Resource Language

English

Resource Character Set

utf8

Resource Security Classification

unclassified

Geographic Extent

North bound
-26.0
East bound
153.0
West bound
112.0
South bound
-44.0

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-719c-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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