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The Musgrave Province, Central Australia Unravelling the tectonic framework of the Musgrave Province, central Australia Benjamin P. Wade, B.Sc (Hons) Geology and Geophysics School of Earth and Environmental Sciences The University of Adelaide This thesis is submitted in fulfilment of the requirements for the degree of Doctor of Philosophy in the Faculty of Science, University of Adelaide September 2006 Chapter 1 Introduction 1.1 Project Overview and Aims 1995; Myers et al., 1996; Scott et al., 2000; Cawood and Tyler, 2004; Giles et al., 2004; Occhipinti et The 1.60-1.08 Ga Musgrave Province in central al., 2004; Tyler, 2005; Betts and Giles, 2006; Wade southern Australia occupies a vast area (~120,000 et al., 2006). The Musgrave Province is km2) (Figure 1.1), however it comprises the least geographically central to, and younger than, these known Proterozoic terrain in Australia. The accreted Archaean-Palaeoproterozoic fragments construction of a cohesive and data-rich geological (Figure 1.2). This makes it a key element in the framework for the evolution of the Musgrave assembly of Proterozoic Australia, and therefore Province has been hampered by two factors. any models that attempt to describe the evolution of Proterozoic Australia require a sound framework 1) There is a paucity of outcrop beyond the for the geologic evolution of the Musgrave Province. main topographic ranges of the Province; The aim of this thesis was to develop a framework 2) Approximately 80% of the land in the for the protracted geological evolution of the Musgrave Province falls within the traditional Musgrave Province, starting from its earliest history Anangu Pitjantjatjara, Yankunytjatjara and (early Mesoproteorozic), to its latest (early Ngaanyatjarra lands, creating significant difficultly Cambrian) (Figure 1.3). Also of interest was in obtaining access to regions. determining the timing of the final amalgamation of Proterozoic Australia. This was conducted Due to a range of studies over the past decade, utilising geochemical, isotopic, and it is now generally accepted that convergent plate geochronological means. In order to achieve this margin processes played an important role in the aim a five-module program was constructed that assembly of the various Archaean-Proterozoic involved: fragments of Australia (e.g. Zhao and McCulloch, 129°00 132°00 N 25°00 Petermann Ranges Amadeus Basin W oo dro f fe Mt Aloysius Hinckley Ranges Mulga Park Mann Domain Cohn Ranges Kulgera N.T. Hill ° Area 26 00 T Ma omkinson nn Champ De S.A. Ranges H T Mars inc Deering hru kle Amata st y F Hills ault F Mt ault ? ? West Musgrave Ranges ? Fregon Levinger Ferdinand Fault Domain Graben Moorilyanna W inti ginna Fault Graben 27°00 Indulkana Lindsay Fault Range Fault Birksgate Range Eromanga Everard Basin Officer Basin Ranges Thrust 0 50 100 km W.A. Inferred Basement ca. 1.2-1.05 Ga granite Neoprot-Camb sediments Amphibolite facies ca. 1.3 Ga orthogneiss ca. 1.08-1.04 Ga and granite volcanics/sediments Granulite facies ca. 1.4-1.36 Ga Giles mafic-ultramafic intrusions metasediments 1600-1540 Ma Figure 1.1 Location map of the Musgrave Province indicating main areas of fieldwork undertaken in this study and areas of interest. 1 Chapter 1 Introduction Musgrave Province (Figure 1.3) has prohibited a 3. The genesis and tectonic significance of the coherent region-wide evaluation of the mechanisms layered intrusions of the mafic-ultramafic Giles involved in the formation of the Musgrave Province. Complex; 1.2 Outline and organisation of thesis 4. The genesis of the intracratonic Petermann Orogeny as it is recorded in the sediments of the This thesis is organised in a manner that Officer Basin. systematically provides geochemical and isotopic constraints to address a number of elements 5. The genesis of the granitic gneiss of the relating to the tectonic environment pertaining to Coompana Block, and the subsequent implications the formation of various lithologies within the for Proterozoic reconstructions of Australia. Musgrave Province, and also the boundaries with other tectonic domains. These elements are: Chapter 2 summarises the regional geological framework of the Musgrave Province. Despite the 1. The origin of the ca. 1.60-1.54 Musgravian fact that it occupies a large portion of central Gneiss of the Musgrave Province, and the Australia, the Musgrave Province represents one implications for the timing of reconstruction models of the least studied terranes of Proterozoic Australia. involving fragments of Proterozoic Australia; An attempted summary of the results and interpretations of published papers and Ph.D 2. The source of metasediments in the eastern theses, as well as results recorded by State Musgrave Province, and the subsequent Geological surveys is presented in the paper. The implications for pre-Rodinia palaeogeographic chapter is divided into a description of the individual reconstructions involving Australia; lithological units, structural framework, metamorphic Musgrave Province Time (Ma) Mulga Park Domain Fregon Domain D7 ? ? D7 550 D6 PETERMANN OROGENY D6 D5 ? ? D5 D4 ? ? D4 800 Amata Dyke Swarm Felsic volcanics Mafic intrusive 1000 Unnamed olivine dolerites Layered Mafic Intrusion Tjauwata Group Giles Tollu Group Post 1.3 Ga Rocks D3 D3 Felsic intrusive Alcurra Dykes ? ? Complex Alcurra Dykes 1100 ? Unconformity Pitjantjatjara Pitjantjatjara Supersuite Supersuite D2 MUSGRAVE D2 Protolith 1200 OROGENY Volcanic Mafic-intermediate intrusive Un-named 1300 D1 ? ? Orthogneiss D1 ? Metasedimentary ???? Felsic intrusive 1400 ? ? Un-named Pre 1.2 Ga Gneissic Rocks Metasediments Metamorphism/ Deformation ??????? 1500 Pre-D1? Olia Birksgate Gneiss Complex 1600 Figure 1.3 Musgrave Province lithostratigraphic sequence 3 Chapter 1 Introduction A B C D E F G H Amata Dyke FIgure 1.4 (A) Felsic gneiss of the Birksgate Complex, Deering Hills; (B) Mafic gneiss of the Birksgate Complex, Deering Hills; (C) Weathered metapelitic rock of the Birksgate Complex, Deering Hills; (D) Folded quartzite of the Deering Hills; (E) Calc- silicate of the Birksgate Complex, Deering Hills; (F) Example of Pitjantjatjara Supersuite Granite, eastern Musgraves; (G) Example of magmatic layering within the Giles Complex, Caroline intrusion; and, (H) Example of Amata Dyke cross-cutting felsic and mafic gneiss of the Birksgate Complex, Deering Hills. 4 Chapter 1 Introduction record, and possible tectonic significance of the Chapter 7 investigates the age and petrogenetic Musgrave Province. origin of a granitic gneiss located to the west of the Gawler Craton under cover, in what is termed Chapter 3 describes the geochemistry and Nd the Coompana Block. This module was conducted isotopic characteristics of a suite of ca. 1.60-1.54 following the interpretation of results from Chapter Ga felsic orthogneisses that comprise the basement 4, primarily to locate potential sources of zircons in the northern Musgrave Province. This study within the metasedimentary rocks of the eastern provides the first detailed geochemical and isotopic Musgrave Province. analysis of this magmatic event. Limited geochemical work on equivalent felsic rocks in the The thesis is concluded in Chapter 8 with a western Musgrave Province conclude a possible summary of the implications derived from the plate margin origin (e.g. Glikson et al., 1996; Wade results of this study. This section summarises the et al., 2006). By discriminating the tectonic origin findings of the thesis and investigates the of these felsic orthogneisses through geochemical implications of these results for reconstructions of and isotopic means, it allows us to place constraints Proterozoic Australia. on the evolution of the Musgrave Province during the early Mesoproterozoic. Several parts of this thesis have been published or submitted in varying forms to international Chapter 4 reports U-Pb SHRIMP and U-Pb LA- journals. Chapter 2 has been submitted as a ICPMS geochronological and Nd isotope data on review paper to a special volume of Precambrian metasedimentary rocks from the eastern Musgrave Research concentrated on Proterozoic Australia. Province. Originally mapped as part of the ca. Chapter 3 has been published in the Journal of 1.60-1.54 Ga basement Musgravian Gneiss (Conor, Geology, and Chapter 4 has been submitted to 1987), detrital zircon geochronology was and is in review in Geology. Chapter 5 has been undertaken to ascertain possible source regions submitted and in review at the Journal of Petrology. to aid in reconstructions of Proterozoic Australia. Chapter 6 is published in the Journal of the Geological Society of London, and Chapter 7 has Chapter 5 presents geochemical and radiogenic been submitted and is in review at the Australian isotopic data (Nd-Sr) of sample traverses over Journal of Earth Sciences. Appendix 5 has been three intrusions of the mafic-ultramafic Giles submitted to and is in review at Computers and Complex within the western Musgrave Province Geosciences. I have also been involved in a of South Australia. Detailed mapping and sampling number of related projects that are in submission of the Kalka, Ewarara, and Gosse Pile intrusions in international peer reviewed journals. As the has been previously undertaken during the early structure of this project has been focussed on 1970s (e.g. Goode, 1970; Moore, 1970); however, producing each chapter as a stand-alone detailed geochemical and isotopic analysis has manuscript, there is some repetition in the not been applied. The aim is to understand the geological background sections
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