SE6
Weathering, Tectonics and Climate Coupling in the Himalaya

Main Organiser
Sunil K. Singh, Physical Research Laboratory, PGSDN, Physical Research Laboratory, Navrangpura, Ahmedabad -9, India.
sunil@prl.ernet.in

Co-Organiser(s)
Youngsook Huh, Northwestern University, huh@earth.northwestern.edu
huh@earth.northwestern.edu

D. Zhang, HongKong University
zhangd@hkucc.hku.hk

Brief Description
The orogeny of the Himalaya and the intense physical erosion and chemical weathering of this young mountain belt have significantly influenced the elemental and sediment cycles of the globe. A number of studies have addressed to the causes and the impact of the higher erosion and weathering in the Himalayan Tibetan Plateau (HTP). However, our understanding of the sources and sinks of sediments and those of dissolved components in rivers of HTP remains poor. Chemical weathering rates are moderately high in the HTP. As in physical erosion, the relative significance of various factors regulating chemical weathering are also only poorly understood. Despite a number of studies on the chemical and isotope compositions of HTP rivers, silicate/carbonate weathering rates in the HTP remains a matter of debate and hence estimates of CO2 consumption by silicate weathering remain imprecise. Have the weathering rates in the Himalaya remained same over time? Reconstruction of paleo-weathering in HTP will improve our understanding of weathering-climate connection and also provide inputs to geochemical models on elemental cycles. An approach needs to be evolved to track the past weathering rates in the HTP. In this special session, some of these issues pertaining to the Himalaya would be addressed. These include: (i) Sources and sinks of sediments in the HTP rivers and estimates of total erosion rates (ii) Factors regulating physical and chemical weathering in HTP and their relative significance (iii) Rates of silicate weathering in the HTP, its impact on carbon and other elemental/isotope cycles and global climate. (iv) Temporal variations in physical and chemical weathering in the Himalaya: Magnitude and influence on geochemical cycles.