Paper No. 127-2
Presentation Time: 9:00 AM-6:30 PM
THE 2.0-1.1 GA PIERCING POINTS CONNECTING WESTERN LAURENTIA, EAST ANTARCTICA AND AUSTRALIA IN COLUMBIA AND RODINIA
East Antarctica (EA), Australia and Laurentia had a long-lived cratonic association between ~2.0-1.1 Ga, forming Columbia between ~2.0-1.8 Ga, persisting through the Paleo- and Mesoproterozoic, and culminating in assembly of Rodinia between ~1.1-0.6 Ga. Correlation of Neoproterozoic strata in EA and southwest Laurentia (Moores, Geology, 1991; Dalziel, Geology, 1991) provided a revolutionary hypothesis for their association in Rodinia, but this juxtaposition can be extended much deeper in time based on age and isotopic identification of distinctive piercing points (Dalziel, Roy. Soc. Edinburgh, 2013), including the following correlations: (1) 3.1-1.7 Ga Mawson Continent in East Antarctica and southern Australia with the Mojave Province; (2) 2.01 Ga granitoids in EA with Miltalie gneiss of the Gawler Craton; (3) 1.85 Ga granitoids in EA and Gawler Craton with orthogneisses of the Clearwater-Priest River complexes in northern Idaho; (4) coeval ~1.7 Ga igneous and metamorphic events in EA, Gawler Craton, and Mojave Province, likely sourced as detrital sediment in southwest Laurentia; (5) ~1.6 Ga volcanic breccias and associated IOCG deposits in northwestern Canada and eastern Australia; (6) ~1.57 Ga igneous rocks in EA and Gawler Craton with Priest River-Laclede orthogneiss in northern Idaho; (7) 1.45 Ga granitoids in EA with A-type granites of the elongate but truncated Laurentian belt, including widespread detritus; (8) 1.21 Ga granitoids in EA with the AMCG intrusive suite in New Mexico and eastern California; (9) alignment of 1.06 Ga igneous and metamorphic events in EA with the Grenville Province at its termination in Texas; and (10) diagnostic age and isotopic signatures in Cryogenian rift-margin strata of East Antarctica, Australia and Laurentia, recording onset of the rift-to-drift phase of Rodinia breakup between ~710-650 Ma. These age and isotopic piercing points, along with detrital zircon provenance and sediment isotopic compositions, robustly link the EA interior, southern Australia, and western Laurentia over a prolonged period during development of Columbia between 2.0-1.8 Ga, intra-cratonic or craton-margin tectonism between 1.85-1.45 Ga, Mesoproterozoic intra-cratonic magmatism at ca. 1.45 and 1.21 Ma leading to assembly of Rodinia, and eventual breakup in the late Neoproterozoic.