PROTEROZOIC MOUNT ISA SYNTHESIS P.G. Betts & R.J. Armit PGN Geoscience Section II: Eastern Australian Proterozoic correlations Proterozoic Mount Isa Synthesis Page ii Section II: Eastern Australian Proterozoic Correlations Proterozoic Mount Isa Synthesis SECTION II: EASTERN AUSTRALIAN PROTEROZOIC CORRELATIONS Table of Contents INTRODUCTION................................................................................................................... 1 ARCHITECTURAL CONTEXT OF THE CORRELATIONS ......................................................... 3 CONTINENTAL CRATONIC ELEMENTS .................................................................................................3 North Australian Craton .......................................................................................................................3 South Australian Craton........................................................................................................................3 West Australian Craton........................................................................................................................4 RECONSTRUCTION ARCHITECTURES ...................................................................................................4 TECTONIC EVOLUTION OF THE AUSTRALIAN CONTINENT................................................ 6 AMALGAMATION OF THE NORTH AUSTRALIAN CRATON (CA 1870–1820 MA)....................6 Mount Isa Inlier.......................................................................................................................................6 Correlations with the Gawler Craton ................................................................................................8 Correlation with the Arunta Inlier-Tanami Province ........................................................................9 Kimberley Craton–Pine Creek Inlier ..................................................................................................9 Interior of the North Australian Craton...........................................................................................10 Tectonic Interpretation .......................................................................................................................10 COLLISION OF THE WEST AND NORTH AUSTRALIAN CRATONS (CA 1820–1790 MA).....11 Basin Development .............................................................................................................................11 Collision between the West Australian Craton and the Central Australian Craton...............12 Tectonic Interpretation .......................................................................................................................12 LEICHHARDT SUPERBASIN DEVELOPMENT (CA 1790–1760 MA)..............................................13 Mount Isa Inlier....................................................................................................................................13 Leichhardt Superbasin correlations .................................................................................................14 Orogenesis in Central Australia.......................................................................................................14 Tectonic Interpretation .......................................................................................................................15 WONGA EXTENSION EVENT (CA 1760–1740 MA).....................................................................16 Mount Isa Inlier....................................................................................................................................16 Basin Development in the continent interior...................................................................................17 Plate margin magmatism...................................................................................................................17 Tectonic Interpretation .......................................................................................................................17 MID BASIN INVERSION (CA 1740–1725 MA)................................................................................18 Mount Isa Inlier....................................................................................................................................18 Kimban Orogeny and Strangways Event ......................................................................................19 Tectonic Interpretations......................................................................................................................19 CALVERT SUPERBASIN I (ca 1725–1690 Ma) ................................................................................21 Calvert Superbasin correlations.......................................................................................................22 Kimban Orogeny/Strangways Event (continued).........................................................................23 Tectonic Interpretation .......................................................................................................................23 CALVERT SUPERBASIN II (ca 1690–1670 Ma) ...............................................................................25 Correlations..........................................................................................................................................26 Plate Margin tectonism ......................................................................................................................26 Page iii Proterozoic Mount Isa Synthesis Tectonic Interpretation .......................................................................................................................27 ISA SUPERBASIN (ca 1670–1645 Ma).............................................................................................28 Mount Isa Inlier....................................................................................................................................28 Lower Isa Superbasin correlations...................................................................................................29 Tectonic Interpretation .......................................................................................................................30 RIVERSLEIGH EVENT (CA 1645–1630 MA) .....................................................................................31 Upper Isa Superbasin correlations..................................................................................................31 Accretion in Central Australia...........................................................................................................32 Tectonic Interpretation .......................................................................................................................32 ISA SUPERBASIN (CA 1630–1595 MA)............................................................................................32 EARLY ISAN OROGENY (CA 1620–1570 MA)...............................................................................33 CORRELATED OROGENIC EVENTS....................................................................................................34 Chewings Orogeny.............................................................................................................................34 Olarian Orogeny................................................................................................................................34 Painter Orogeny.................................................................................................................................35 Wartakan Orogeny...........................................................................................................................35 Kararan Orogeny...............................................................................................................................35 Ewamin Orogeny ................................................................................................................................36 EVIDENCE FOR PLATE BOUNDARIES DURING THE ISAN OROGENY ........................................36 St Peter Suite Magmatic arc (Gawler Craton) .............................................................................36 Musgrave Magmatic arc ...................................................................................................................37 Forest Home Suite...............................................................................................................................37 LATE ISAN OROGENY (CA 1550–1500 MA) .................................................................................38 CORRELATED OROGENIC EVENTS....................................................................................................39 Jana Orogeny.....................................................................................................................................39 Late Orogenic A-type Granites.......................................................................................................39 DRIVING OROGENESIS...................................................................................................... 41 Plume modified orogeny...................................................................................................................41 Continental collision between the Gawler Craton and the North Australian Craton ............42 East-west shortening followed by transpression...........................................................................42