COMPOSITION AND ORIGIN OF THERMAL WATERS IN THE GULF-OF-SUEZ AREA, EGYPT

Thermal waters with discharge temperatures ranging from 32 to 70 degre es C are being discharged along the Gulf of Suez (Egypt) from springs and shallow artesian wells. A comprehensive chemical and isotopic stud y of these waters supports previous suggestions that the waters are pa leometeoric waters from the Nubian sandstone aquifer. The chemical and isotopic compositions of solutes indicate possible contributions from Tertiary sedimentary aquifer rocks and windblown deposits (marine aer osols and/or evaporite dust) in the recharge area. There is no chemica l or isotopic evidence for mixing with Red Sea water. Gas effervescenc e from the Hammam Faraoun thermal water contains about 4% CH4 (delta(1 3)C = -32.6 parts per thousand) and 0.03% He having an isotopic ratio consistent with a mixture of crustal and magmatic He (He-3/He-4 = 0.26 R(n)). Geothermometers for the thermal waters indicate maximum equili bration temperatures near 100 degrees C. The waters could have been he ated by percolation to a depth of several km along the regional geothe rmal gradient. Copyright (C) 1996 Published by Elsevier Science Ltd.