Mulder, J and Halpin, J and Daczko, N and Meffre, S and Orth, K and Thompson, J and Morrissey, L, Locating hidden terrane boundaries in East Antarctica with detrital feldspar Pb isotopes, Australian Geoscience Council Convention Abstracts, 14-18 October 2018, Adelaide, South Australia, pp. 362. (2018) [Conference Extract]
Official URL: http://agcc.org.au/
Here, we test the Mirny Fault as a key suture between Indo-Antarctica and Australo-Antarctica using Pb isotopes of detrital feldspars from offshore sediments referenced to new and compiled feldspar Pb isotopic data from onshore exposures of Indo-Antarctica and Australo-Antarctica. The feldspar Pb-isotope signature of Indo-Antarctica forms a broad population with ˛⁰⁷Pb/˛⁰⁴Pb ratios of 15.5—16.1 and ˛⁰⁶Pb/˛⁰⁴Pb of 17—19. In contrast, Australo-Antarctica has a feldspar Pb-isotope signature characterised by a tight cluster of ˛⁰⁷Pb/˛⁰⁴Pb (15.5—15.8) and ˛⁰⁶Pb/˛⁰⁴Pb (16.5—17) ratios, which is distinct from Indo-Antarctica. Locally-derived Holocene sediments offshore of the Mirny region contain detrital feldspars with Pb-isotope compositions recording a contribution from both Indo-Antarctica and Australo-Antarctica.
The presence of Australo-Antarctic and Indo-Antarctic crust near the Mirny Fault supports the interpretation of this structure as a fundamental terrane boundary. We interpret the Mirny Fault as the key suture between Indo-Antarctica and Australo-Antarctica and trace this boundary into the interior of East Antarctica to connect with an inferred Gondwanan-aged suture within the Gamburtsev Subglacial Mountains.
|Item Type:||Conference Extract|
|Keywords:||Antarctica, Gondwana, Kuunga Orogen, feldspar|
|Research Division:||Earth Sciences|
|Objective Division:||Expanding Knowledge|
|Objective Group:||Expanding Knowledge|
|Objective Field:||Expanding Knowledge in the Earth Sciences|
|UTAS Author:||Halpin, J (Dr Jacqueline Halpin)|
|UTAS Author:||Meffre, S (Dr Sebastien Meffre)|
|UTAS Author:||Orth, K (Dr Karin Orth)|
|UTAS Author:||Thompson, J (Mrs Jennifer Thompson)|
|Deposited By:||Oceans and Cryosphere|
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