THE BURMA PLATELET IN SOUTHEAST ASIA: A CENOZOIC ANALOGUE FOR THE BAJA-BC COASTWISE TRANSLATIONS

The Burma Platelet is a 1200 km long sliver plate stretching along the Burmese subduction margin. It is today being dragged by the northwards convergence of the Indian plate, as a result of the hyper-oblique convergence of India relative to Indochina. Its amount of coastwise translation has been estimated at about 400 to 1000 km since the late Miocene, but its earlier tectonic history remains poorly documented. This talk investigates the amount of coastwise translation of the Burma Platelet during the Cenozoic based on new paleomagnetic and geochronological data from 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 displacement have been significantly underestimated. Paleomagnetic data suggest up to 2500 km of northward translation of the Burma Platelet at a relatively moderate pace since the Late Cretaceous, which is supported by sedimentary provenance data from central Myanmar. The amplitude and duration of the lateral translation of the Burma Platelet thus provides a potential analogue to the coastwise translations of terranes along the western margin of North America.