Authors / CoAuthors
Champion, D.C.
Abstract
The `Inferred Isotopic Domain Boundaries of Australia data set is based on an interpretation of the recently released Neodymium depleted mantle model age map of Australia (GA Record 2013/44). The isotopic map of Australia was produced by gridding two-stage depleted mantle model ages calculated from Sm-Nd isotopic data for just over 1490 samples of felsic igneous rocks throughout Australia. The resultant isotopic map serves as a proxy for bulk crustal ages and accordingly allows the potential recognition of geological domains with differing geological histories. One of the major aims of the Neodymium depleted mantle model age map, therefore, was to use the isotopic map (and associated data) to aid in the recognition and definition of crustal blocks (geological terranes) at the continental and regional scale. Such boundaries are recognisable by regional changes in isotopic signature but are hindered by the variable and often low density of isotopic data points. Accordingly two major procedures have been adopted to locate the regional distribution of such boundaries across the geological continent. In areas of high data density (and high confidence), such as the Yilgarn Craton Western Australia, isotopic data alone was used to delineate crustal domains. In such regions it is evident that identified crustal blocks often but not universally approximate known geological terranes. In areas of moderate data density (and corresponding moderate confidence) (smoothed) boundaries of known geological provinces were used as a proxy for the isotopic boundary. For both high and moderate data densities identified crustal boundaries were extended (with corresponding less confidence) into regions of lower data density. In areas of low data density (and low confidence) boundaries were either based on other geological and/or geophysical data sets or were not attempted. The latter was particularly the case for regions covered by thick sedimentary successions. Two levels of confidence have been documented, namely the level of confidence in the location of the isotopic domain boundary, and the level of confidence that a boundary may actually exist. The `Inferred Isotopic Domain Boundaries of Australia map shows the locations of inferred boundaries of isotopic domains, which are assumed to represent the crustal blocks that comprise the Australia continent. The map therefore provides constraints on the three dimensional architecture of Australia, and allows a better understanding of how the Australian continent was constructed from the Mesoarchean through to the Phanerozoic. It is best viewed as a dynamic dataset, which will need to be refined and updated as new information, such as new isotopic data, becomes available.
Product Type
dataset
eCat Id
83700
Contact for the resource
Custodian
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- GIS DatasetNational
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2015-01-01T00:00:00
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unknown
Topic Category
geoscientificInformation
Series Information
Lineage
Unknown
Parent Information
Extents
[-44.0, -10.0, 113.0, 155.0]
Reference System
Spatial Resolution
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