New Mexico Geological Society Annual Spring Meeting — Abstracts

Two distinct types of ore mineralization are superimposed in the northern portion of the district: (1) base metal sulfide manto replacements and (2) hot spring vein and breccia deposits with abundant telluride minerals. Ore fluids for both deposit types utilized the same conduits and localization structures.

The overprint of tellurium on the sulfide assemblage is manifested by tellurides replacing sulfides on the undersides of the mantos and veinlets of tellurides cutting manto ore. Telluride occurrences in the sulfides are only found in proximity to quartz-fluorite hot spring material. In addition, telluride compositions reflect the mineralogy of the sulfide ores. Paragenetic relationships in the telluride ores are: galena-acanthite (manto) -> altaite-hessite -> native tellurium, indicating an increasing tellurium activity with time. Ores which contain stable sulfides, with respect to high tellurium activities, are devoid of tellurides. Those deposits containing sulfide phases unstable under high Te activities show telluride replacement. Abundant fluorite accompanies the Te mineralization and is absent in the manto ores.