GLS Seminar: Dr. Elizabeth Catlos, "From Mineral Grain to Mountain Range: Perspectives on the Evolution of the Himalayas"

Friday, September 8th, 2006 from 3:30 PM – 4:30 PM, 4069 Derring Hall

Refreshments will be served at 4:30 PM. The public is cordially invited.

From Mineral Grain to Mountain Range: Perspectives on the Evolution of the Himalayas

Dr. Elizabeth Catlos, Oklahoma State University

The Himalayan mountain range, created by the collision of India with Asia which began 50 million years ago, is an ideal laboratory for understanding the response of continental lithosphere to plate tectonic forces. Metasedimentary rocks that once made up the leading edge of the Indian island today form the summits of Himalayan peaks. The range is presently characterized by high rates of seismicity and deformation, and widespread exposure of post-collisional high-grade metamorphic and igneous rocks implies long-term, large-scale vertical transport. The distribution of rock types within the range has, for over one hundred years, inspired theories of crustal metamorphism which have been exported to explain aspects of other mountain belts. Over the past 25 years, a number of geodynamic models have been proposed that make quantitative predictions regarding the petrologic and tectonic evolution of the Himalaya. However, it is only with the advent of the high resolution ion microprobe that we have been able to test these models by directly determining the timing of metamorphism. Th-Pb dating of small (~15 µm-sized) minerals from rocks obtained adjacent the crustal-scale faults that have created the highest mountain range on this planet yield remarkably young ages. As is often the case in science, understanding the largest scale features requires knowledge of the microscale; the signal with which to explain the processes involved when two continents collide is preserved within crystals only 10 µm in size.