Applying Rare Earth Elements, Uranium, and87Sr/86Sr to Disentangle Structurally Forced Confluence of Regional Groundwater Resources: The Case of the Lower Yarmouk Gorge

Christian Siebert,Eyal Shalev,Eliahu Rosenthal,Fabien Magri,Peter Möller,Marwan Al-Raggad,Tino Rödiger

doi:10.1155/2019/6727681

Abstract

The conjoint discussion of tectonic features, correlations of element concentrations,δ18O,δD, and87Sr/86Sr of groundwater leads to new insight into sources of groundwater, their flow patterns, and salinization in the Yarmouk Basin. The sources of groundwater are precipitation infiltrating into basaltic rock or limestone aquifers. Leaching of relic brines and dissolution of gypsum and calcite from the limestone host rocks generate enhanced salinity in groundwater in different degrees. High U(VI) suggests leaching of U from phosphorite-rich Upper Cretaceous B2 formation. Both very low U(VI) and specific rare earth element including yttrium (REY) distribution patterns indicate interaction with ferric oxyhydroxides formed during weathering of widespread alkali olivine basalts in the catchment area. REY patterns of groundwater generated in basaltic aquifers are modified by interaction with underlying limestones. Repeated sampling over 18 years revealed that the flow paths towards certain wells of groundwater varied as documented by changes in concentrations of dissolved species and REY patterns and U(VI) contents. In the Yarmouk Gorge, groundwater with basaltic REY patterns but high U(VI) and low Sr2+and intermediate sulfate concentrations mainly ascends in artesian wells tapping a buried flower structure fault system crossing the trend of the gorge.

Highlights

Since Roman times, the hot springs of Hamat Gader (HG), Israel, and Ain Himma, Jordan, in the Lower Yarmouk Gorge (LYG) were used for health care (Figure 1)
By major and minor elements and distribution patterns of rare earth elements including yttrium, it was ascertained that thermal groundwater discharging through springs in the LYG is infiltrated in basaltic regions of the Hauran plateau, Syria [1]
Depending on the sampling location, the results are classified in the following way: Mukheibeh well field (M1-M13), Ain Himma (AH), Hamat Gader springs (HG), Meizar wells (Me1-Me3), and the Yarmouk River (YR)

Summary

Introduction

Since Roman times, the hot springs of Hamat Gader (HG), Israel, and Ain Himma, Jordan, in the Lower Yarmouk Gorge (LYG) were used for health care (Figure 1). Hydrogeological and hydrochemical studies of springs and well waters in the gorge reveal that groundwater of widely different composition discharges at short distances [1]. By major and minor elements and distribution patterns of rare earth elements including yttrium ( termed REY), it was ascertained that thermal groundwater discharging through springs in the LYG is infiltrated in basaltic regions of the Hauran plateau, Syria [1]. Parts of these waters are mixed in various proportions with limestone water from Ajloun. The recent study is based on 18 years of repeated sampling of wells and springs and reveals significant variations in REY patterns and element concentrations suggesting

Results

Discussion

Conclusion