Abstract

The basic architecture of the Himalayan orogen is well established. Two colliding continents have greatly thickened the continental crust by both ductile and brittle deformation causing the metamorphic core of the orogen to be being rapidly extruded southwards. Melting of this metamorphic core is widespread, resulting in migmatites and leucogranites distributed across the breadth of the orogen. What is less clear is the role this anatexis may have played in the extrusion process, perhaps enhanced by rapid erosion at the surface due to the focused monsoon precipitation on the southwards facing slopes of the Lesser Himalaya.

In this talk I trace the causes and mechanisms of melting and explore the role of anatexis in the tectonic evolution of the Himalaya. I then draw comparisons with the Caucasus orogen that shares many similarities yet differs in one key respect: the highest Caucasian peaks are massive stratovolcanoes that are entirely lacking in the Himalaya.