A New Method of Estimating Denudation Rates of the High Himalaya Based on Metamorrphic Index Minerals in the Siwalik Molasse

The erosion record of the high-grade metamorphic complex of the Himalaya is preserved in the Siwalik foreland molasse. Here we propose a new method for estimation of average denudation rates in the High Himalaya during the Miocene based on the first appearance of kyanite in the Middle Siwaliks (beginning at ∼11 Ma) and of sillimanite in the Upper Siwaliks (at ∼5 Ma) and from ahe fact that these metamorphic index minerals were formed at depths of 21-24 km(thermobarometric data) during the main Himalayan metamorphic event at ∼23 Ma (geochronologic data).