Salinization of porewater in a multiple aquitard-aquifer system in Jiangsu coastal plain, China

Journal Article · Fri Dec 15 04:00:00 EST 2017 · Hydrogeology Journal

DOI:https://doi.org/10.1007/S10040-017-1622-0· OSTI ID:22780901

Li, Jing; Liang, Xing ^[1]; Zhang, Yanian ^[2]; Liu, Yan ^[3]; Chen, Naijia; Abubakari, Alhassan; Jin, Menggui ^[1]

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1. China University of Geosciences, School of Environmental Studies (China)
2. Changjiang Institute of Survey Technical Research (China)
3. Key Laboratory of Ministry of Land and Ground Fissure Disaster (China)

Chemical and isotopic compositions were analyzed in porewater squeezed from a clayey aquitard in Jiangsu coastal plain, eastern China, to interpret the salinity origin, chemical evolution and water-mass mixing process. A strong geochemical fingerprint was obtained with an aligned Cl/Br ratio of 154 in the salinized aquitard porewater over a wide Cl{sup −} concentration range (396–9,720 mg/L), indicating that porewater salinity is likely derived from a mixing with old brine with a proportion of less than 20%. Very small contributions of brine exerted limited effects on water stable isotopes. The relationships between porewater δ{sup 18}O and δD indicate that shallow and intermediate porewaters could be original seawater and were subsequently diluted with modern meteoric water, whereas deep porewaters with depleted stable isotopic values were probably recharged during a cooler period and modified by evaporation and seawater infiltration. The cation–Cl relationship and mineralogy of associated strata indicate that porewater has been chemically modified by silicate weathering and ion-exchange reactions. {sup 87}Sr/{sup 86}Sr ratios of 0.7094–0.7112 further confirm the input source of silicate minerals. Numerical simulations were used to evaluate the long-term salinity evolution of the deep porewater. The alternations of boundary conditions (i.e., the third aquifer mixed with brine at approximately 70 ka BP, followed by recharge of glacial meltwater at 20–25 ka BP, and then mixing with Holocene seawater at 7–10 ka BP) are responsible for the shift in porewater salinity. These timeframes correspond with the results of previous studies on ancient marine transgression-regression in Jiangsu coastal plain.

• OSTI ID: 22780901
• Journal Information: Hydrogeology Journal, Journal Name: Hydrogeology Journal Journal Issue: 8 Vol. 25; ISSN 1431-2174
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
AQUIFERS
BOUNDARY CONDITIONS
BRINES
CHINA
CHLORINE IONS
GROUND WATER
GROUNDWATER RECHARGE
ION EXCHANGE
ISOTOPE RATIO
MINERALOGY
OXYGEN 18
SALINITY
SEAWATER
SILICATE MINERALS
SILICATES
STRONTIUM 86
STRONTIUM 87
WEATHERING