OFFSHORE FRESHENED GROUNDWATER IN THE SUBAQUEOUS PALEO-DELTA OF THE PEARL RIVER IN THE NORTHERN SOUTH CHINA SEA
Offshore freshened groundwater (OFG) refers to water stored in geological formations beneath the seabed, which has significantly lower salinity compared to the seawater above it. The estimated global volume of OFG is in the order of 105 – 106 km3. While it has been reported that OFG is widely distributed throughout the global continental shelf system, the study of OFG is still in its early stages, particularly in the South China Sea. This lack of understanding is primarily stems from the limited knowledge about the mechanisms and timing of OFG generation and evolution. In light of this, the objective of this thesis is to investigate the occurrence, dynamics, hydrochemical characteristics, and evolution history of the offshore groundwater system using the subaqueous paleo-delta of the Pearl River in the Northen South China Sea as a case study. To achieve this objective, a combination of various methods is employed, including offshore borehole drilling, geophysical surveying, biogeochemical analysis, paleo-hydrogeological modeling, and high-resolution isotope geochemical fingerprinting. By leveraging a comprehensive database and numerical modeling, the knowledge derived from this study can be applied not only to the Pearl River Estuary but also to other similar offshore regions, fostering a broader understanding and facilitating practical applications in the context of large-river deltaic estuaries worldwide.
Additional information: Mr. Chong SHENG, chongsh@connect.hku.hk