Guide to using the Australian Mafic-Ultramafic Magmatic Events gis dataset



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Guide to using the Australian Mafic-Ultramafic Magmatic Events GIS Dataset

Archean, Proterozoic and Phanerozoic Magmatic Events

Geoscience Australia
RECORD 2014/39

Jane P. Thorne, Michelle Cooper and Jonathan C. Claoué-Long



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Department of Industry

Minister for Industry: The Hon Ian Macfarlane MP
Parliamentary Secretary: The Hon Bob Baldwin MP
Secretary: Ms Glenys Beauchamp PSM

Geoscience Australia

Chief Executive Officer: Dr Chris Pigram
This paper is published with the permission of the CEO, Geoscience Australia

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© Commonwealth of Australia (Geoscience Australia) 2014

With the exception of the Commonwealth Coat of Arms and where otherwise noted, all material in this publication is provided under a Creative Commons Attribution 3.0 Australia Licence. (http://www.creativecommons.org/licenses/by/3.0/au/deed.en)

Geoscience Australia has tried to make the information in this product as accurate as possible. However, it does not guarantee that the information is totally accurate or complete. Therefore, you should not solely rely on this information when making a commercial decision.

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ISSN 2201-702X (PDF)

ISBN 978-1-925124-28-6 (PDF))

GeoCat 78742



Bibliographic reference: Thorne, J.P., Cooper, M. and Claoué-Long, J.C., 2014. Guide to using the Australian Mafic-Ultramafic Magmatic Events GIS Dataset: Archean, Proterozoic and Phanerozoic Magmatic Events. Record 2014/39. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2014.039

Contents

Guide to using the Australian Mafic-Ultramafic Magmatic Events GIS Dataset 1

Archean, Proterozoic and Phanerozoic Magmatic Events 1

Executive Summary 6

Executive Summary 6

Appendix AScope of the Map 8

Appendix AScope of the Map 8

Appendix BMethods 9

Appendix BMethods 9

B.1Sequence of Development 10

B.1Sequence of Development 10

B.2Sources of Geochronological Data and Digital Dataset 11

B.2Sources of Geochronological Data and Digital Dataset 11

B.3Crustal Elements 13

B.3Crustal Elements 13

B.4Definition of Magmatic Events 16

B.4Definition of Magmatic Events 16

B.5Definition of Igneous Provinces 19

B.5Definition of Igneous Provinces 19

B.6Spatial Representation of Magmatic Events 20

B.6Spatial Representation of Magmatic Events 20

B.7GIS Dataset Specifications 21

B.7GIS Dataset Specifications 21

Appendix CAssociated Maps and Reports 22

Appendix CAssociated Maps and Reports 22

Appendix DHoatson, D.M., Claoué-Long, J.C. and Jaireth, S., 2008. Map of Australian Proterozoic mafic-ultramafic magmatic events, Sheets 1 and 2, 1:5 000 000 map, Geoscience Australia. 22

Appendix EHoatson, D.M., Jaireth, S., Whitaker, A.J., Champion, D.C. and Claoué-Long, J.C., 2009. Map of Australian Archean mafic-ultramafic magmatic events, Sheets 1 and 2, 1:5 000 000 map, Geoscience Australia. 22

Appendix FClaoué-Long, J.C. and Hoatson, D.M., 2009. Map of Australian Proterozoic Large Igneous Provinces, Sheets 1 and 2, 1:5 000 000 map, Geoscience Australia. 22

Appendix GHoatson, D.M., Claoué-Long, J.C. & Jaireth, S., 2008. Guide to Using the Australian Proterozoic Mafic-Ultramafic Magmatic Events Map. Record 2008/015. Geoscience Australia, Canberra. 22

Appendix HHoatson, D.M., Jaireth, S., Whitaker, A.J., Champion, D.C. & Claoué-Long, J.C., 2009. Guide to Using the Australian Archean Mafic-Ultramafic Magmatic Events Map. Record 2009/041. Geoscience Australia, Canberra. 22

Appendix IClaoué-Long, J.C. & Hoatson, D.M., 2009. Guide to using the Map of Australian Proterozoic Large Igneous Provinces. Record 2009/044. Geoscience Australia, Canberra. 22

Appendix JMafic-Ultramafic Magmatic Events Time Series 23

Appendix JMafic-Ultramafic Magmatic Events Time Series 23

J.1Time-Space-Event Charts 36

J.1Time-Space-Event Charts 36

Appendix KApplications and Conclusions 37

Appendix KApplications and Conclusions 37

Acknowledgements 42

Acknowledgements 42

References 43

References 43

Appendix LDigital Datasets used in this Study 44

L.1Archean compilation 45

L.2Proterozoic compilation 47

L.3Phanerozoic compilation 50

Appendix MAttributes, Definitions and Values 51

Appendix NMafic-Ultramafic Magmatic Events 56

Appendix OTime-Space-Event Charts 65

Appendix PReferences used in the compilation 68



Table of Figures

Executive Summary

This document provides supporting information to assist in the use of the Australian Mafic-Ultramafic Magmatic Events GIS Dataset. The dataset is made publicly available as a GIS at nominal 1:5 000 000 scale, and shows the time-space-event distribution of mafic-ultramafic magmatism in Australia from the early Archean to the present day.

Development of this GIS has been a multi-year project and earlier released extracts (in viewable PDF form with accompanying Geoscience Australia Records) included compilations for the Archean magmatic record, the Proterozoic magmatic record, and the Australian Large Igneous Provinces (LIPs). Publication of the GIS completes the series with addition of the Phanerozoic magmatic record, and formalisation of the complete record of Archean-Phanerozoic magmatic events as a single series.

The chronology of Australian mafic-ultramafic magmatism resolves into 74 magmatic events within, predominately, resolvable bands of ±10 million years (Myr). Each event is identified by geological units grouped by similar age – this coeval magmatism may or may not be genetically related and may be in response to different geodynamic environments. These magmatic events range in age from the Eoarchean ~3730 Ma ME 1 – Manfred Event, confined within a small remnant domain within the Yilgarn Craton, to the widespread record of Cenozoic magmatism in eastern Australia (ME 72 to ME 74). The magmatic events range in magnitude from the giant volumes of magma in Large Igneous Provinces, to events whose only known occurrence is an isolated record of dated mafic igneous rock in a single drillhole. The GIS makes it possible to focus on the location of any one of these magmatic events, or groups of magmatic events that may be of interest, and overlay context from any other information that users may have available.

The delineation of magmatic events for this study is based on several hundred published ages of mafic and ultramafic igneous rocks from different isotopic systems and minerals. In addition to their ages and extents, primary recorded aspects of each magmatic event include the presence or absence of ultramafic components. Further to this, the presence or correlation of known magmatic-related mineralisation is highlighted in Time-Space-Event Charts of Australia (Appendix O, figures D1 and D2). The basis for mapping has been regional solid geology, interpreted basement geology and surface geology base maps made available by the State and Northern Territory geological surveys, providing insight into the total areal extent of the magmatic systems under cover. Also available to complement the Event GIS are the domains and element boundaries from the Australian Crustal Elements map. These boundaries which are which are based on geophysical extrapolation of crustal elements under the cover of continental basins, provide a framework of the shallow crustal structure of the continent, and are used in this guide. The Crustal Elements digital dataset is available for download from the Geoscience Australia website.

Insight into the geodynamic development of the continent is provided by the magmatic event structure through time. The compilation draws attention to concentrations of mafic-ultramafic magmatism in the Archean from ~2820–2665 Ma, in the Proterozoic from ~1870–1590 Ma, and in the late Neoproterozoic-Phanerozoic from ~530–225 Ma. These three time spans contain 39 of the 74 magmatic events, 53% of the entire mafic-ultramafic magmatic event record of the continent. The periods in between have mafic-ultramafic magmatic records that are more dispersed in time. Other features of interest include the shared geographic and crustal element locations of Large Igneous Provinces and numerous events with smaller magma volumes.

In the Archean, only three mafic-ultramafic magmatic events are known to be mineralised, but one of these (the ~2705 ME 19 Kambalda Event) is the basis of much of Australia’s world-leading production of komatiite-hosted nickel. Exploration is yet to discover world class examples of magmatic-related mineralisation in Australia’s Proterozoic and Phanerozoic magmatic events. Nine Proterozoic and nine Phanerozoic magmatic events in Australia, however, do have discovered resources, indicating that the mineral system is present in those magmatic events. The compilation identifies that every magmatic event corresponding to world-class magmatic mineral deposits in other continents is also represented in Australia, with the sole exception of the ~2585 Ma Great Dyke mineralisation in Zimbabwe. These correlations of mineralisation, both within Australia and with magmatic mineralisation in other continents, are a basis for investigating mineral potential in under-explored parts of igneous provinces, especially where they extend under cover.

The Australian Mafic-Ultramafic Magmatic Events GIS Dataset is a fundamental national framework within which to integrate other geological, geochemical and geophysical datasets, and to evaluate pointers to under-explored and potentially mineralised environments. As a compilation of all mafic-ultramafic magmatic events, large and small, this is currently the most detailed magmatic event record available for any continent. It provides the detailed basis from which to constrain the role of the mantle and mafic-ultramafic magmatism in the development of the Australian continent, and the correlation with other continents.

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