Tuesday, June 11, 2013

Was South China Once a Part of India (Geologically Speaking)?



Locating South China in Rodinia and Gondwana: A fragment of greater India lithosphere?

Authors:

1. Peter A. Cawood (a,b)
2. Yuejun Wang (c)
3. Yajun Xu (d)
4. Guochun Zhao (e)

Affiliations:

a. Department of Earth Sciences, University of St Andrews, North Street, St Andrews KY16 9AL, UK

b. Centre for Exploration Targeting, School of Earth and Environment, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia

c. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China

d. State Key Laboratory of Biogeology and Environmental Geology, Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074, China

e. Department of Earth Sciences, University of Hong Kong, Pokfulam Road, Hong Kong, China

Abstract:

From the formation of Rodinia at the end of the Mesoproterozoic to the commencement of Pangea breakup at the end of the Paleozoic, the South China craton first formed and then occupied a position adjacent to Western Australia and northern India. Early Neoproterozoic suprasubduction zone magmatic arc-backarc assemblages in the craton range in age from ca. 1000 Ma to 820 Ma and display a sequential northwest decrease in age. These relations suggest formation and closure of arc systems through southeast-directed subduction, resulting in progressive northwestward accretion onto the periphery of an already assembled Rodinia. Siliciclastic units within an early Paleozoic succession that transgresses across the craton were derived from the southeast and include detritus from beyond the current limits of the craton. Detrital zircon age spectra require an East Gondwana source and are very similar to the Tethyan Himalaya and younger Paleozoic successions from Western Australia, suggesting derivation from a common source and by inference accumulation in linked basins along the northern margin of Gondwana, a situation that continued until rifting and breakup of the craton in the late Paleozoic.

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