https://doi.org/10.5194/hess-2021-246 Preprint. Discussion started: 20 May 2021 c Author(s) 2021. CC BY 4.0 License. 1 Saline groundwater evolution in Luanhe River Delta, China since 2 Holocene: hydrochemical, isotopic and sedimentary evidence 3 Xianzhang Dang1, 2, 3, Maosheng Gao2, 4,, Zhang Wen1,, Guohua Hou2, 4, 4 Daniel Ayejoto1, Qiming Sun1, 2, 3 5 1School of Environmental Studies, China University of Geosciences, 388 Lumo Rd, Wuhan, 430074, 6 China 7 2Qingdao Institute of Marine Geology, CGS, Qingdao, 266071, China 8 3Chinese Academy of Geological Sciences, Beijing, 100037, China 9 4Laboratory for Marine Geology, Pilot National Laboratory for Marine Science and Technology, 10 Qingdao, 266071, China 11 Correspondence to: Maosheng Gao (
[email protected]), Zhang Wen (
[email protected]) 1 https://doi.org/10.5194/hess-2021-246 Preprint. Discussion started: 20 May 2021 c Author(s) 2021. CC BY 4.0 License. 1 Abstract 2 Since the Quaternary Period, palaeo-seawater intrusions have been suggested to 3 explain the observed saline groundwater that extends far inland in coastal zones. The 4 Luanhe River Delta (northwest coast of Bohai Sea, China) is characterized by the 5 distribution of saline, brine, brackish and fresh groundwater, from coastline to inland, 6 with a wide range of total dissolved solids (TDS) between 0.38–125.9 g L-1. 7 Meanwhile, previous studies have revealed that this area was significantly affected by 8 Holocene marine transgression. In this study, we used hydrochemical, isotopic, and 9 sedimentological methods to investigate groundwater salinization processes in the 10 Luanhe River Delta and its links to the palaeo-environmental settings.