Seminar

Silicate weathering is a fundamentally important process on Earth due to its ability 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). A way to justify these variations is to identify geologic mechanisms that are able to enhance and reduce weathering processes, which can dramatically alter Earth’s climate and lead to such states. Rivers are a useful way to study weathering process as they carry the weathering products to the ocean. Southeast Asia theoretically features the highest weathering rates around the world 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. Therefore, we aim to sample an extensive set of S.E Asian rivers to better understand first-order weathering processes in the region. We also aim to better understand the utility of paleo-weathering proxies and with our main focus being the lithium isotopic system (δ⁷Li). It is a relatively new technique, and the early signs are promising as a powerful paleo-weathering proxy as fractionation between ⁶Li and ⁷Li occurs during silicate weathering and clay mineral formation, thus reflecting weathering intensity.

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