When the Indian and Asian plates collided to form the Himalayas starting 45 million years ago (mya), sheets of rock were thrust up and exposed at the surface. These sheets, known as nappes, provide windows into the formation of the mountain building event. In the northern Indian Himalayas lies the Tso Morrari nappe. This area has linear intrusions of magma from the Ordovician Period (~450 Mya) that were metamorphosed into eclogites, rocks formed at extremely high pressures and temperatures. In this study, we used an electron microprobe and a scanning electron microscope to analyze the trace element chemistry of the eclogites. These chemical data were used to reconstruct the pressure and temperature paths of formation of the Tso Morrari eclogites. These data support the idea that the eclogites form at anomalously high pressure (called ultra high pressure) areas within the mountain belt, suggesting that these rocks were exhumed from deep within the Himalayas.
Nicole Ahline, ’15
Sponsor: Emily Walsh