Stavely Project Report 12 - Exhumation and preservation history of the Stavely Arc in western Victoria: a low-temperature thermochronology study
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Product description:Introduction: The Stavely Project is a collaborative geoscience research project between Geoscience Australia and the Victorian Department of Economic Development, Jobs, Transport and Resources (represented by the Geological Survey of Victoria). The aim of the Stavely Project is to improve the understanding of the regional geological architecture and mineral prospectivity of western Victoria, in particular the Cambrian-aged Stavely Arc. Executive Summary: This report contains estimates on the timing and the amount of exhumation of the Cambrian bedrock of the Stavely region of western Victoria. Cambrian porphyry copper mineralisation is associated with rocks of the Stavely Arc in at least one locality near Willaura. The shallow crustal emplacement of such deposits, and associated systems, makes them very sensitive to being removed by even limited amounts of erosion. Low-temperature thermochronological analysis from eleven samples of fresh Cambrian sedimentary bedrock from drill holes, petroleum wells and water bores covering the length and breadth of the Grampians-Stavely Zone was undertaken to understand the timing and amount of exhumation across the prospective region. Samples were analysed using the three complementary systems of apatite fission-track analysis, apatite (U-Th-Sm)/He and zircon (U-Th)/He) dating. The differing temperature sensitivity of each system tracks the cooling history of the rocks from about 200°C down to about 35°C as they are exhumed towards the surface. Most of the samples show similar cooling pathways, with exhumation towards the surface by the Triassic at 250–200 Ma with no evidence for any further significant exhumation or burial since that time. The similarity of the cooling pathways for all samples suggests a relatively uniform exhumation level and therefore the potential preservation of Cambrian porphyry copper mineralisation (and related systems) across the whole Grampians-Stavely Zone. Bibliographic reference: Kohn, B., Chung, L., Taylor, D. & Alimanović, A., 2019. Exhumation and preservation history of the Stavely Arc in western Victoria: a low-temperature thermochronology study. Stavely Project Report 12, Geological Survey of Victoria. Department of Jobs, Precincts and Regions. Download: The downloadable version of this report is supplied in PDF format High Res (17.4MB) and MS Word text only (237kb). | ||||||
