Characterization and Dating of Saline Groundwater in the Dead Sea Area

Abstract

ABSTRACT. This work presents an attempt to date brines and determine flow rates of hypersaline groundwater in the extremely dynamic system of the Dead Sea (DS), whose level has dropped in the last 30 yr by ~20 m. The processes that affect the carbon species and isotopes of the groundwater in the DS area were quantified in order to estimate their flow rate based on radiocarbon and tritium methods. In contrast to the conservative behavior of most ions in the groundwater, the carbon system parameters indicate additional processes. The dissolved inorganic carbon (DIC) content of most saline groundwater is close to that of the DS, but its stable isotopic composition ( 13 C DIC ) is much lower. The chemical composition and carbon isotope mass balance suggest that the low  13 C DIC of the saline groundwater is a result of anaerobic organic matter oxidation by bacterial sulfate reduction (BSR) and methane oxidation. The radiocarbon content ( 14 C DIC ) of the saline groundwater ranged from 86 pMC (greater than the ~82 pMC value of the DS in the 2000s) to as low as 14 pMC. The similarity between the 14 C DIC value and Na/Cl ratio of the groundwater at the DS shore and that of the 1980s DS brine indicates that the DS penetrated to the aquifer at that time. The low 14 C DIC values in some of the saline groundwater suggest the existence of ancient brine in the subaquifer.

Anaerobic oxidation of methane by sulfate in hypersaline groundwater of the Dead Sea aquifer

“…The behavior of these ions (sodium and chloride) in the aquifer, which is under‐saturated with respect to halite, is expected to be conservative. On the other hand, the carbon system, which was studied mainly through measurements of DIC, δ 13 C DIC , and alkalinity, exhibits non‐conservative behavior (Avrahamov et al ., ).…”

Modeling radium distribution in coastal aquifers during sea level changes: The Dead Sea case

“…Other elements that are affected by water-rock interaction such as uranium (which decreases in the saline groundwater) and Fe (which increases, Table 3) may also be sensitive to saline groundwater circulation. Avrahamov et al (2010) showed that the carbonate system is also affected by saline groundwater circulation where the DIC and d 13 C values decrease. These chemical changes in the circulating Dead Sea water may have implications for the Dead Sea water chemistry regarding radium isotopes and other trace elements.…”

Reconstruction and Optimization of Tritium Time Series in Precipitation of Beijing, China

“…Tritium ( 3 H) has been used in earth and environmental sciences for several decades (Leboucher et al 2004;Varlam et al 2010;Zhai et al 2011), especially in groundwater studies to calculate the recharge rate and to identify the presence of modern recharge (Liu 1995;Noakes et al 1998;Celle et al 2001;Avrahamov et al 2010). Since Kaufman and Libby (1954) first proposed that tritium could be utilized for groundwater dating, it has been applied in many regions of the world (e.g.…”