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Proterozoic basin evolution and tectonic geography of Madagascar during the Nuna/Columbia Supercontinent
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  • Sheree Ellen Armistead,
  • Alan S Collins,
  • Renata da Silva Schmitt,
  • Raisa Costa,
  • Bert De Waele,
  • Théodore Razakamanana,
  • Justin Payne,
  • John Foden
Sheree Ellen Armistead
Geological Survey of Canada & Laurentian University

Corresponding Author:[email protected]

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Alan S Collins
Adelaide University
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Renata da Silva Schmitt
Universidade Federal do Rio de Janeiro
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Raisa Costa
Universidade Federal do Rio de Janeiro
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Bert De Waele
Fortescue Metals Group Ltd.
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Théodore Razakamanana
Université de Toliara
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Justin Payne
University of South Australia
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John Foden
University of Adelaide
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Abstract

Madagascar hosts several Paleoproterozoic sedimentary sequences that are key to unravelling the geodynamic evolution of past supercontinents on Earth. New detrital zircon U–Pb and Hf data, and a substantial new database of ~15,000 analyses are used here to compare and contrast sedimentary sequences in Madagascar, Africa and India. The Itremo Group in central Madagascar, the Sahantaha Group in northern Madagascar, the Maha Group in eastern Madagascar, and the Ambatolampy Group in central Madagascar have indistinguishable age and isotopic characteristics. These samples have maximum depositional ages > 1700 Ma, with major zircon age peaks at c. 2500 Ma, c. 2000 Ma and c. 1850 Ma. We name this the Greater Itremo Basin, which covered a vast area of Madagascar in the late Paleoproterozoic. These samples are also compared with those from the Tanzania and the Congo cratons of Africa, and the Dharwar Craton and Southern Granulite Terrane of India. We show that the Greater Itremo Basin and sedimentary sequences in the Tanzania Craton of Africa are correlatives. These also tentatively correlate with sedimentary protoliths in the Southern Granulite Terrane of India, which together formed a major intra-Nuna/Columbia sedimentary basin that we name the Itremo-Muva-Pandyan Basin. A new Paleoproterozoic plate tectonic configuration is proposed where central Madagascar is contiguous with the Tanzania Craton to the west and the Southern Granulite Terrane to the east. This model strongly supports an ancient Proterozoic origin for central Madagascar against the Tanzania Craton of East Africa.
Mar 2021Published in Tectonics volume 40 issue 3. 10.1029/2020TC006498