Geology and mineral resources of the Northern Territory Ahmad M and Munson TJ (compilers) Northern Territory Geological Survey Special Publication 5 Chapter 28: Georgina Basin BIBLIOGRAPHIC REFERENCE: Kruse PD, Dunster JN and Munson TJ, 2013. Chapter 28: Georgina Basin: in Ahmad M and Munson TJ (compilers). ‘Geology and mineral resources of the Northern Territory’. Northern Territory Geological Survey, Special Publication 5. Disclaimer While all care has been taken to ensure that information contained in this publication is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of its information. The Northern Territory of Australia gives no warranty or assurance, and makes no representation as to the accuracy of any information or advice contained in this publication, or that it is suitable for your intended use. You should not rely upon information in this publication for the purpose of making any serious business or investment decisions without obtaining independent and/or professional advice in relation to your particular situation. The Northern Territory of Australia disclaims any liability or responsibility or duty of care towards any person for loss or damage caused by any use of, or reliance on the information contained in this publication. Georgina Basin Current as of February 2011 Chapter 28: GEORGINA BASIN PD Kruse, JN Dunster and TJ Munson INTRODUCTION of similar age to the Georgina Basin and form distinct depocentres that are separated from the Georgina Basin by The Georgina Basin is a polyphase intracratonic basin basement ridges formed by basaltic rocks of the Kalkarindji containing unmetamorphosed Cryogenian to Devonian Province (Tickell 2005, see 'DO\%DVLQ¿JXUH). In the sedimentary rocks (Figure 28.1). It covers an area of middle Cambrian, the interconnected Georgina, Wiso and 330 000 km2 in the central-eastern NT and extends into Daly basins collectively formed part of a vast depositional western Queensland. The basin is bounded to the northeast area that extended across northern, central and southern and east by Proterozoic terranes of the McArthur Basin, Australia; contiguous portions of this depositional system South Nicholson Basin, Lawn Hill Platform and Mount in northern and central Australia are referred to in this Isa Inlier, and to the west by the Proterozoic Tomkinson, volume as the Centralian B Superbasin (see Centralian Warramunga and Davenport provinces of the Tennant Superbasin). The northern and southeastern portions of Region. To the south, the contact with the Palaeoproterozoic the Georgina Basin are overlain by Mesozoic sedimentary Aileron Province of the Arunta Region is a steep south- rocks of the onshore Carpentaria and Eromanga basins, side-up thrust fault system. The Georgina Basin is respectively. continuous with the Daly and Wiso basins, to the northwest The Georgina Basin comprises two distinct domains: and southwest of the Tennant Region, respectively. These a southern basinal depocentre (southern Georgina Basin), neighbouring basins contain stratigraphic successions essentially south of latitude 21°S, incorporating Cryogenian, 133° 135° 137° 139° 15° McArthur Basin 0125 km Carpentaria Murphy Basin Province 17° Lawn Hill South Nicholson Carpentaria Basin Tomkinson Platform Basin Province MOUNT 19° TENNANT South Lawn Hill Nicholson Platform Basin Leichhardt River Fault Wiso Tennant Creek Trough, Ewan Block, Basin ISA Warramunga Myally Shelf Province NT Eastern REGION QLD Succession Mount Isa INLIER 21° Davenport Kalkadoon- ARUNTA Province Leichhardt Belt Aileron Province 23° Irindina REGION Province Amadeus Basin Alice Springs Eromanga Aileron Basin Province A11-227.ai Mesozoic–Cenozoic Neoproterozoic– Palaeozoic Figure 28.1. Regional geology of early Cambrian Palaeo–Mesoproterozoic Georgina Basin. NT geological regions Kalkarindji Province basins Palaeo–Mesoproterozoic from NTGS 1:2.5M GIS database. Georgina Basin NORTHERN orogens TERRITORY Qld geological regions simpli¿ed and QUEENSLAND slightly modi¿ed from Denaro and road State boundary Dhnaram (2009). Box shows area of SOUTH AUSTRALIA Figure 28.2. rail Mount Isa locality Geology and mineral resources of the Northern Territory 28:1 Special publication 5 Georgina Basin Ediacaran, Cambrian, Ordovician and Devonian magnetic granitoids, forming a region of thickened, successions (Dunster et al 2007); and a central-northern, stable crust with relatively low heat Àow and low crustal quiescent platform (central and northern Georgina Basin) temperatures. These last two domains were inferred to north of that latitude, including some late Neoproterozoic underlie the majority of the southern Georgina Basin. sedimentary rocks, early Cambrian Kalkarindji Province The age of the Altjawarra domain is controversial. rocks and a relatively thin, platformal middle Cambrian Several authors, including Elkedra (2001), inferred an succession. Neoproterozoic rocks in the southern Georgina Archaean age, but all available geochronological data (Cross Basin form a part of the ‘Centralian Superbasin’ succession et al 2005) and extrapolation of the magnetic signature of Walter et al (1995), referred to in this volume as the in the subsurface from the Jervois district suggest that it Centralian A Superbasin (see Centralian Superbasin). is Palaeoproterozoic. The lack of any preferred mineral orientation in the oldest absolutely dated granitoids in the Basement domain (1846 Ma in NTGS99/1, 1805 Ma in Lucy Creek-1), together with the lack of any pervasive geophysical grain, Palaeo–Mesoproterozoic strata of the McArthur Basin suggest that the domain has behaved as a rigid block, at are presumed to underlie the central and northern parts of least since that time. A second major phase of moderately to the Georgina Basin; these rocks are probably continuous non-magnetic granitoids was intruded into the Altjawarra with equivalent strata of the Tomkinson Province of domain at about 1750 Ma. the Tennant Region. Similarly aged strata of the South Nicholson Basin, Lawn Hill Platform and Mount Isa Inlier Southern Georgina Basin underlie the basin in the east. Older Palaeoproterozoic rocks, equivalent to those in the Murphy Province and/ The NT portion of the southern Georgina Basin, south of or Warramunga Province of the Tennant Region, may in latitude 21°S, encompasses the following mapsheets: in turn underlie these strata, at least in part. Basaltic rocks of the southeast, northern HAY RIVER1, TOBERMOREY, the Kalkarindji Province immediately underlie and form SANDOVER RIVER, HUCKITTA and ELKEDRA; basement for middle Cambrian successions over most of and in the southwest, northern ALCOOTA, BARROW the central and northern Georgina Basin and the contiguous CREEK, northeastern NAPPERBY and eastern MOUNT northern Wiso and Daly basins. In the southern Georgina PEAKE (Kruse and Mohammed 2005, Figure 28.1). The Basin, basement consists of probable Palaeoproterozoic southern part of the basin includes the thickest sedimentary rocks that were assigned by Teasdale and Pryer (2002) successions and is the most structured. and Dunster et al (2007) to three proposed basement The southern Georgina Basin includes strata of domains (Figure 28.2): the Davenport domain was Neoproterozoic (Cryogenian to Ediacaran), early interpreted as being a ca 10 km-thick Palaeoproterozoic Palaeozoic (Cambrian to Ordovician) and Devonian age rift-basin succession; the Dulcie domain was interpreted ()LJXUHV , 28.4). The Neoproterozoic succession as a Palaeoproterozoic felsic gneiss terrane intruded by comprises the Plenty, Aroota, Keepera and Mopunga groups; voluminous syn- to post-tectonic non-magnetic granitoids; and the Altjawarra domain was interpreted as comprising 1 Names of 1:250 000 and 1:100 000 mapsheets are in large and large ma¿c-intermediate intrusive bodies and late non- small capital letters respectively, eg HAY RIVER, WOODGREEN. 133°30' 135° 136°30'138° 21° BARROW CREEK ELKEDRA SANDOVER RIVER Davenport domain NT QLD Dulcie domain 22° ALCOOTA HUCKITTA TOBERMOREY Altjawarra domain 0 50 km Aileron Province 23° ALICE SPRINGS ILLOGWA CREEK HAY RIVER Irindina Province A11-234.ai Georgina Basin ALCOOTA 1:250 000 mapsheet State boundary Figure 28.2. Basement domains of Northern Territory portion of southern Georgina Basin (modi¿ed from Teasdale and Pryer 2002). Location shown in Figure 28.1. Geology and mineral resources of the Northern Territory 28:2 Special publication 5 Georgina Basin 133°30' 135° 136°30' 138° KATHERINE URAPUNGA ROPER RIVER CAPE BEATRICE 15° LARRIMAH HODGSON DOWNS MOUNT YOUNG PELLEW McArthur Basin 16° DALY WATERS TANUMBIRINI BAUHINIA DOWNS ROBINSON RIVER NORTHERN TERRITORY Carpentaria Basin 17° NEWCASTLE WATERS BEETALOO WALHALLOW CALVERT HILLS Devonian Cravens Creek Beds 18° SOUTH LAKE WOODS HELEN SPRINGS BRUNETTE DOWNS MOUNT DRUMMOND Dulcie Sandstone South Nicholson Ordovician Basin Toko Group medial late Cambrian– Tomkinson early Early Ordovician Province Cockroach Group 19° GREEN SWAMP WELL TENNANT CREEK ALROY South RANKEN Cambrian–early late Cambrian TENNANT Nicholson Barkly Group Basin Narpa Group Georgina Basin Shadow Group Wiso Basin Neoproterozoic Warramunga Kiana Group Province 20° LANDER RIVER BONNEY WELL FREW RIVER AVON DOWNS Mopunga Group Keepera Group NT Aroota Group QLD Plenty Group REGION Davenport ALROY 250K mapsheet 21° Province MOUNT PEAKE BARROW CREEK ELKEDRA SANDOVER RIVER fault ARUNTA Mesozoic–Cenozoic early Cambrian Kalkarindji Province Neoproterozoic– Palaeozoic 22° Palaeo–Mesoproterozoic