Hydrochemistry, evolution, and origin of brines in supratidal saline pans, south Jeddah, Red Sea coast, Saudi Arabia

作者：Taj Rushdi J; Aref Mahmoud A^*

来源：Arabian Journal of Geosciences, 2015, 8(10): 8835-8851.

DOI：10.1007/s12517-015-1799-2

• Brine chemistry
• Evolution
• Genesis
• Saline pans
• Seawater seepage
• Saudi Arabia

The supratidal, saline pans and surrounding wet sabkha area, south Jeddah, Saudi Arabia, have seawater seepages with a salinity of 40 aEuro degrees that increases to 80-140 and 220-375 aEuro degrees during deposition of gypsum and halite, respectively. The concentration order of the dominant cations and anions in the saline pans is sodium (Na+) > magnesium (Mg2+) > potassium (K+) > calcium (Ca2+) and chloride (Cl-) > sulfate ions (SO4 (2-)) > bicarbonate ions (HCO3 (-)), respectively. The dominant brine type is Mg and sodium chloride. Correlations of the various ions in the saline pans indicate positive relations between Na+ and Cl-, Na+ and total dissolved solids (TDS), and Cl- and TDS due to halite precipitation at a high salinity value. Negative correlations between Ca2+ and SO4 (2-) and between Ca2+ and HCO3 (-) are related to the reduction of SO4 (2-) and oxidation of organic matter by sulfate-reducing bacteria, which is confirmed also by the positive correlation of HCO3 (-) and alkalinity. The high Mg/Ca ratio is related to the enrichment of the brine with bittern salts such as MgCl2 and KCl. The chemical data of the brines indicate their source from recent and old marine waters of MgCl2 and CaCl2 characters. The contribution of meteoric water has a minor effect on the composition of the brine in the saline pans.

• 出版日期2015-10