Authors / CoAuthors
Jackson, M.J. | Southgate, P.N. | Black, L.P.
Abstract
The 1:100,000 series of maps for Palaeoproterozoic rocks of the Leichhardt River Fault Trough and Lawn Hill Platform of northern Australia arguably form the best set of regional geological maps in the country. Since their release in the 1970?s and early 1980?s they have been extensively used in mineral exploration programs in the Mount Isa Inlier. In this region one of the most obvious lithostratigraphic correlations is based on the assumed equivalence of two sandstone bodies, 1) the Torpedo Creek Quartzite and 2) the Warrina Park Quartzite. Each sandbody forms the basal lithostratigraphic unit of its respective Group (McNamara and Mount Isa) and outcrops as prominent ridges of white quartzite, readily traceable on aerial photographs. The distinctive outcrop character, map patterns and defined stratigraphic relationships have resulted in this correlation forming the `linch-pin? of lithostratigraphic subdivision in the region. Sequence stratigraphic analysis of the Warrina Park and Torpedo Creek Quartzites, the underlying Surprise Creek Formation and overlying fine-grained transgressive siliciclastics has identified a series of chronostratigraphically significant surfaces (sequence boundaries, transgressive surfaces and maximum flooding surfaces) that collectively demonstrate major miscorrelations in the current lithostratigraphic subdivisions. The study demonstrates the potential for major errors associated with lithostratigraphic subdivisions based on the assumed equivalence and continuity of sandbodies. In the case of the Mt Isa region the miscorrelations have resulted in major unconformities with up to 20 my of missing rock record remaining unrecognised in many areas. The consequences of such miscorrelations are inadequate and inaccurate reconstructions of basin geometry, stratigraphic architecture and the mis-identification of synsedimentary growth faults. Because these reconstructions form the essential prerequisites for predictive mineral system models, aimed at constraining the evolution and flow of metal-bearing fluids through these sediments, these inadequacies are of fundamental importance to the exploration industry. This scenario is well recognised in the petroleum industry, where significant effort is made to correctly understand sandbody geometry particularly in reservoir settings where continuity is critical to production and reservoir engineering. The paper provides an example of sandbody miscorrelations in the Palaeoproterozoic successions of northern Australia. Issues raised in this paper are of major significance to the mineral exploration industry as well as state geological surveys and universities involved in mapping programs and basin reconstructions.
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nonGeographicDataset
eCat Id
40375
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Keywords
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- External PublicationScientific Journal Paper
- ( Theme )
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- sequence stratigraphy
- ( Theme )
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- geochronology
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- PG
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2003-01-01T00:00:00
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[-11.0, -10.0, 148.5, 150.0]
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