Stable isotope investigation of gold-bearing jasperoid in the central Drum Mountains, Utah

Abstract

The oxygen, hydrogen, carbon, and sulfur isotope relationships in gold-bearing jasperoid and associated carbonate and pyrite from the Drum Mountains, Utah, have been studied for the purpose of determining certain genetic relationships of these mineral occurrences. Relative deuterium depletion in inclusion fluids and 18 O depletion in quartz and carbonates indicate participation of large quantities of heated ground waters in the formation of these bodies. The delta 13 C values near zero imply a sedimentary source but allow a minor component of magmatic carbon for the carbonates, whereas delta 34 S values near zero suggest a magmatic source of sulfur for the pyrite. Oxygen isotope and fluid inclusion temperatures of 125 degrees to 255 degrees C establish a hypogene origin for the jasperoid, and this finding has important economic implications relative to the possible occurrence of additional quantities of gold-bearing jasperoid at depth in the Drum Mountains.