Lateral translation of the Burma Platelet since the late Cretaceous: An Asian analogue for the Baja-BC hypothesis?

Abstract : The Burma Platelet is a 1200 km long sliver plate stretching along the Burmese subduction margin. It is commonly seen as being dragged by the northwards convergence of the Indian plate since the late Miocene, as a result of the hyper-oblique convergence of India relative to Indochina and the opening of the Andaman Sea. This talk proposes an overview of the history of the Burma Platelet since the Late Cretaceous based on new data from the Myanmar Paleoclimate and Geodynamics Research Group (MyaPGR), including sedimentological, geochronological, and paleomagnetic data from central Myanmar. We show that the Burma Platelet has been forming an individual sliver plate since at least the middle Eocene –and possibly much earlier-- and that the duration and distance of its coastwise translation have been significantly underestimated. Preliminary paleomagnetic data suggest up to 2500 km of northward translation of the Burma Platelet at a relatively moderate pace since the Late Cretaceous, which seems supported by sedimentary provenance data from central Myanmar. The amplitude and duration of the lateral translation of the Burma Platelet provides a potential analogue to the controversial coastwise translations of terranes along the western margin of North America (the famous ‘Baja-BC Hypothesis’). Its mechanisms and triggers remain to be documented.