Quaternary Volcanism in Myanmar: A Record of Indian Slab Tearing in a Transition Zone From Oceanic to Continental Subduction

Abstract Magmatic processes that occur during the transition from oceanic to continental subduction and collision in orogens are critical and still poorly resolved. Oceanic slab detachment in particular is hypothesized to mark a fundamental change in magmatism and deformation within an orogen. Here, we report on two Quaternary volcanic centers of Myanmar that may help us better understand the process of slab detachment. The Monywa volcanic rocks are composed of low‐K tholeiitic, medium‐K calk‐alkaline, and high‐K to shoshonitic basalts with arc signatures, while the Singu volcanic rocks show geochemical characteristics similar to asthenosphere‐derived magmas. These volcanic rocks have low Os concentrations but extremely high 187Os/186Osi ratios (0.1498 to 0.3824) due to minor (