INVESTIGATING CHEMICAL WEATHERING PROCESSES IN RIVERS DRAINING THE NAGALAND MANIPUR OPHIOLITE SEQUENCES, EASTERN INDIA

The weathering of silicate minerals regulates climate on million-year timescales. Here we test a hypothesis that the weathering of ultramafic terrains generated by arc-continent collisions could be responsible for rapid atmospheric carbon drawdown. We examine samples gathered from tributaries of the Tizu River in Eastern India to assess weathering rates within the Naga Hills Ophiolites. Major cations, anions, trace elements, Li isotopic and clay mineralogical compositions were measured from river water, bedload, and suspended sediment samples to gain insight on silicate weathering processes in the region. The Tizu river feeds into the Chindwin and Irrawaddy rivers of Myanmar, which contains one of the largest sediment loads in the world. Our chemical analyses will help to examine the impact of this ultramafic system — which is annually exposed to the hot and humid monsoon — in relation to other significant global weathering systems.