Robert O. Rye Mustafa M. Mawad Ralph Jackson Roberts 1978 <p>Massive sulfide deposits and sulfide-bearing veins in Saudi Arabia show a wide range in <span>δ</span>³⁴S values from very negative to strongly positive and cover almost the entire range observed for ore deposits in nature.</p><p>Massive sulfide deposits that have very negative values (Wadi Wassat and Wadi Qatan) formed as syngenetic sedimentary deposits in stagnant, euxinic basins. Deposits that have large positive values (Khnaiguiyah and Al Amar) were formed by sea water hydrothermal systems.</p><p>Gold- and silver-bearing veins whose <span>δ</span>³⁴S values fall near 0 permil (Mand adh Dhahab and Samrah) are believed to have derived both sulfur and metals from magmatic sources. Massive sulfide deposits whose <span>δ</span>³⁴S values range from slightly negative to slightly positive (Kutam, Al Masane, Wadi Bidah, and Jabal Sayid) are thought to have been formed largely from sea water hydrothermal systems, though deep-seated contributions of sulfur cannot be ruled out. Some deposits in this group (Nuqrah and AT Ridayniyah) appear to have derived their sulfur from volcanic exhalative sources.</p> application/pdf 10.3133/ofr78776 en U.S. Geological Survey Preliminary sulfur isotope investigations of mineral deposits in the Precambrian shield, Kingdom of Saudi Arabia reports