Chemistry, Mineralogy and maturity status of Obhor Sabkha, Saudi Arabia

The mineralogy and pore water chemistry of subsoil of the relatively stronger crustal layer above the watertable and the ground water chemistry at two locations in the coastal clayey sabkha areas of Obhor, Saudi Arabia confirm the predominance of evaporites like halite, gypsum, aragonite and calcite and the trend of progressive sabkhaization from top downwards. Of the two locations studied, Station 1 with higher soluble salts contents (TSS up to 28%) in soil and interstitial water salinity (up to 384,200 mg/l) is in a well developed sabkha and Station 2 with lower TSS and salinity is in a slightly developed sabkha as per the classification of Bahafzallanet al. (1993). Clay mineral montmorillonite was identified as a trace (in bulk powder sample) at 45 cm depth at Station 1 and illite at same depth at Station 2 and further work for clay mineral identification is suggested.