Seminar

Silicate weathering is a fundamentally important process to remove CO₂ from the atmosphere. This, coupled with other processes in the carbon cycle, has helped regulate climate over multimillion-year timescales through a strong negative feedback mechanism. Throughout its history, Earth has experienced a wide range of different climate states (such as “icehouse” and “greenhouse” conditions). These climatic variations are hypothesized to be driven by geologic mechanisms that are able to enhance and/or reduce weathering processes. Rivers are a useful way to study weathering processes as they carry the weathering products to the ocean. Southeast Asia theoretically features some of the highest global weathering rates due to the hot and humid tropical climate and the continuous supply of fresh silicate material via the active tectonics; however, Southeast Asian rivers remain poorly studied. My research aims to explore processes governing weathering intensity in the tropics of Asia and west Pacific and quantify regional weathering fluxes. This includes a comparative study between rivers in Hong Kong and the Mariana Islands, focused on major (cation and anion) and trace elements, δ⁷Li isotopic signatures from the dissolved and suspended river loads, and clay mineralogy. Early findings suggest enhanced weathering rates in the Mariana Islands, potentially because of the more active tectonics and favorable mafic bedrock. My future work will expand to river systems in Malaysia Borneo, Philippines, and Indonesia to further improve our Southeast Asian dataset. The Philippines and Indonesia are notably important due to the presence of major ophiolite complexes, which are highly weatherable with a high potential for CO₂ sequestration.

Additional information: Mr. Chris Tsz Long CHEUNG, ctlc@connect.hku.hk