Characteristics and controls of an offshore freshened groundwater system in the Shengsi region, East China Sea

• DOI: 10.3389/feart.2023.1198215
• Publication Date: 2023-06-19T06:49:51Z
• Authors: Ariel T. Thomas; Aaron Micallef; Shuangmin Duan; Zhihui Zou
• Keywords: Seafloor Spreading

Offshore freshened groundwater (OFG) has been encountered in continental margins around the world and identified as a potential unconventional water resource. In China, coastal areas islands face limited freshwater resources. The East China Sea, specifically region north of Shengsi islands, may contain an OFG system hosted buried paleochannels associated with ancient Yangtze river. To assess potential, characteristics, controls this region, we employed integrated modeling approach. We constructed 2D geological model Quaternary sediments based on data from two well sites. By considering sea-level fluctuations over past 200,000 years, conducted paleo-reconstruction flow solute transport conditions transect. compared simulated present-day distribution borehole observations. Our findings indicate that was mostly sub-aerially exposed during period, allowing for meteoric recharge. Numerical results demonstrate high likelihood laterally extensive existing today. mechanism responsible its formation appears to be recharge offshore directed caused by increased hydraulic gradients lowstand. suggests forms oceanward dipping wedge, top occurring approximately 50–100 m below seafloor. Freshwater is likely present down basement at 250 m. geometry volume are strongly influenced shelf stratigraphy. estimate range 0.5 1.6 km 3 -1 , indicating viable resource city Shanghai. gain further insights, recommend conducting additional investigations using geophysical techniques.