The Gawler Craton, South Australia, consists of late Archaean to early Mesoproterozoic igneous and supracrustal lithologies which preserve a deformation history lasting the duration of the Palaeoproterozoic. Understanding the evolution of the Gawler Craton is of significance in global supercontient reconstructions as it preserves evidence for earliest Palaeoproterozoic collisional orogenesis (c. 2460-2430 Ma) and, in conjunction with the North Australian Craton and Antarctica, has often been correlated to the western margin of Laurentia. In addition, the Gawler Craton is also host to the world-class Olympic Dam Fe-oxide-Cu-Au-U type-deposit (world's fourth largest Cu and largest U deposit) and related Fe-oxide-Cu-Au-U and Cu-Au mineralising systems. Despite the various geologically and economically important characteristics of the Gawler Craton there has traditionally been a poor understanding of the tectonothermal evolution of the Gawler Craton, in particular for the Palaeoproterozoic. This study addresses and refines the Palaeo-to Mesoproterozoic tectonothermal evolution of the Gawler Craton. This is done using geochemical, geochronological and isotopic analytical techniques to better understand selected supracrustal and igneous lithologies in the Gawler Craton and the orogenic events which have affected them. Largely unexposed metasedimentary lithologies of the northern Gawler Craton record multiple deformation events but have previously been virtually unconstrained with respect to their timing of protolith deposition and the age of deformation/metamorphism. New geochronological data demonstrate these metasedimentary lithologies were deposited during the time period -1750-1730 Ma before being metamorphosed and deformed during the Kimban (1730-1690 Ma) and Kararan (1570-1545 Ma) Orogenies. Detrital zircon geochronology and isotopic and geochemical characteristics of the sampled metasedimentary lithologies suggest a relatively similar protolith sedimentary succession was deposited across a large extent of the northern Gawler Craton. Detritus for the sedimentary protolith does not appear to have been sourced from the Gawler Craton. Instead the protolith it is more consistent with a North Australian Craton provenance suggesting a proximity between the northern Gawler Craton and North Australian Craton at the time of protolith deposition. The newly defined presence of the Palaeoproterozoic Kimban Orogeny in the northern Gawler Craton demonstrates the Kimban Orogeny to be a major, high-grade, craton-wide orogenic event. This finding contradicts previous suggestions that the northern Gawler Craton was accreted to the proto-Gawler Craton during the later Mesoproterozoic Kararan Orogeny. In addition, previous reconstruction models for the Palaeo-to early Mesoproterozoic often cite the felsic Tunkillia Suite (1690-1670 Ma), western and central Gawler Craton, as representing arc magmatism prior to the subsequent amalgamation of the Gawler Craton during the Kararan Orogeny. New geochemical and isotopic data for the Tunkillia Suite have allowed for re-examination of the tectonic setting for the petrogenesis of the Tunkillia Suite. Contrary to previous suggestions (based upon discrimination diagrams), the mineralogy, geochemistry and isotopic characteristics of the Tunkillia Suite are not consistent with arc-magmatism. Instead the Tunkillia Suite is interpreted to represent a late-to post-tectonic magmatic suite generated during the waning stages of the Kimban Orogeny. This petrogenesis further highlights the importance of the Kimban Orogeny as a fundamental tectonothermal event in the evolution of the Gawler Craton. Subsequent to the Kimban Orogeny, the Gawler Craton was thought to undergo a period of subduction-related magmatism (St Peter Suite) prior to the anorogenic magmatism of the voluminous felsic Gawler Range Volcanic (GRV) and Hiltaba Suite magmatism (1595-1575 Ma). New geochronological data for the ms-bi-gt-bearing peraluminous Munjeela Suite (1590-1580 Ma) have demonstrated the Hiltaba/GRV event was accompanied by significant crustal anatexis not associated with the Hiltaba/GRV magmatism. The Munjeela Suite and metasedimentary enclaves within it demonstrate that the Gawler Craton was likely to be undergoing compressive deformation and crustal thickening sometime during the petrogenesis of the Hiltaba/GRV magmatism. This suggests the Hiltaba/GRV magmatism did not occur in an anorogenic setting as previously proposed. The findings of this study are incorporated into a revised tectonothermal evolution of the Gawler Craton. This is used to discuss previous reconstruction models for Proterozoic Australia and provide a new reconstruction model of Australia and Antarctica during the Palaeoproterozoic. Important facets of the proposed model are links to the Archaean-Early Palaeoproterozoic Sask Craton in the Trans-Hudson Orogen, Laurentia, and the joint evolution of the North Australian and Gawler Cratons throughout the entire Palaeoproterozoic. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1330862 / Thesis (Ph.D.) - University of Adelaide, School of Earth and Environmental Sciences, 2008

This thesis examines the geology of the Daspoort Formation (Pretoria Group, Transvaal Supergroup) of South Africa, with the accent on describing and interpreting its sedimentology. The Palaeoproterozoic Daspoort Formation (c. 2.1‐2.2 Ga) forms part of the Pretoria Group on the Kaapvaal craton. This sandstone‐ and quartzite‐dominated lithological formation covers an elliptical geographical area stretching from the Botswana border in the west to the Drakensberg escarpment in the east, with its northern limit in the Mokopane (Potgietersrus) area and Pretoria in the south; altered outliers are also found in the overturned units of the Vredefort dome in the Potchefstroom area. Deposition of the Daspoort Formation was in a postulated intracratonic basin which applies equally to the entire Transvaal Supergroup succession in the Transvaal depository. Various characteristics from the formation, such as sedimentary architectural elements (e.g., channel–fills etc.), maturity trends and distribution of lithofacies assemblages across the preserved basin give insight into the developing conditions during deposition and genesis of the Daspoort Formation. Subordinate evidence from basic geochemistry, ripple mark data and optical microscope petrology studies support the sedimentary setting inferred for this Palaeoproterozoic deposit. Fluvial and epeiric marine conditions prevailed during the deposition of the Daspoort clastic sediments into the intracratonic basin. This shallow epeiric sea was fed by fluvial influx, predominantly from the west when a transgressive regional systems tract led to the filling of the basin, evolving into the deeper marine Silverton Formation setting, laid down above the Daspoort. Transgression from the east (marine facies predominate) to the west (fluvial facies) is supported by cyclical trends, palaeoenvironmental and palaeogeographical interpretations. Accompanying poorly preserved microbial mat features contribute to the postulated shallow marine environment envisaged for the eastern part of the basin whereas ripple marks and grain size distribution support a fluvial setting for the west, with lithofacies assemblages accounting for both areas’ depositional interpretation. / Dissertation (MSc)--University of Pretoria, 2013. / tm2014 / Geology / Unrestricted