Abor volcanics: Magmatic 'breadcrumbs' on the trail of the Kerguelen mantle plume?

Tuesday, 16 December 2014
Jonathan C Aitchison1, Geoffrey L Clarke1, Trevor R Ireland2, Alan T Baxter3, Santanu K Bhowmik4, Ali Ao5, Faruque Hussain6 and Jason Richard Ali7, (1)University of Sydney, School of Geosciences, Sydney, NSW, Australia, (2)Australian National University, Research School of Earth Sciences, Canberra, Australia, (3)University of New England, School of Environmental and Rural Science, Armidale, Australia, (4)Indian Institute of Technology, Kharagpur, Department of Geology & Geophysics, Kharagpur, India, (5)Indian Institute of Technology Kharagpur, Geology & Geophysics, Kharagpur, India, (6)Assam University, Department of Earth Science, Silchar, India, (7)University of Hong Kong, Dept of Earth Sciences, Hong Kong, Hong Kong
The formation age of the Abor volcanics in the Siang Valley of Aranachal Pradesh, NE India has long been controversial. Two schools of thought prevail. One favors a Permian age with eruption associated with rifting of elements of the Cimmerian continent off the northern margin of Gondwana. The other considers an Eocene age more likely with a magmatic history complicated by India-Asia collision. Although arguments have been presented on the basis of lithostratigraphic and paleomagnetic data similar lithologies in areas of incomplete exposure and rugged terrain together with a lack of precise age control means that stratigraphic control is minimal.

Our zircon LA-ICP-MS and SHRIMP U/Pb dating work potentially sheds surprising new light on the history of these rocks. It is entirely possible that they are in fact of a different age and that their evolution can readily be explained as being part of the Comei (southern Tibet), Sylhet, (Shilling Plateau) Rajmahal, Bunbury (western Australia), Kerguelen Plateau mantle plume trail.