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Successive shifts of the India-Africa transform plate boundary during the Late Cretaceous-Paleogene interval: implications for ophiolite emplacement along transforms
The Arabian Sea in the NW Indian Ocean is a place where two major transform boundaries are currently active : the Owen Fracture Zone between India and Arabia and the Owen Transform between India and Somalia. These transform systems result from the fragmentation of the India-Africa Transform boundary, which initiated about 90 Myrs ago, when the India-Seychelles block separated from Madagascar to move towards Eurasia. Therefore, the geological record of the Arabian Sea makes it possible to investigate the sensitivity of a transform system to several major geodynamic changes.
Here we focus on the evolution of the India-Africa transform system during the ∼47-90 Ma interval. We identify the Late Cretaceous (∼90-65 Ma) transform plate boundary along Chain Ridge, in the North Somali Basin. From 65 to ∼42-47 Ma, the India-Africa transform is identified at the Chain Fracture Zone, which crossed both the Owen Basin and the North East Oman margin. Finally, the transform system jumped to its present-day location in the vicinity of the Owen Ridge. These shifts of the India-Africa boundary with time provide a consistent paleogeographic framework for the emplacement of the Masirah Ophiolitic Belt, which constitutes a case of ophiolite emplaced along a transform boundary. The successive locations of the India-Africa boundary further highlight the origin of the Owen Basin lithosphere incoming into the Makran subduction zone.
Keyword(s)
Transform boundaries, Arabian Sea, Masirah ophiolites
Full Text
File | Pages | Size | Access | |
---|---|---|---|---|
Publisher's official version | 38 | 28 Mo | ||
Supplementary data 1. | - | 306 octets | ||
Author's final draft | 48 | 7 Mo |