Carbon and Oxygen Isotope Studies in Rocks of the Vicinity of the Almadén Mercury Deposit (Province of Ciudad Real, Spain)

Abstract

Carbonate constituents from 36 samples of spilitized basalts, dolerites, possible lamprophyres, pyroclastic tuffs and hydrothermal vein fillinM which occur in the sedimentary fram of the Almad6n mercury deposit show consistently low [j C values of - 6.6 ± 2.20/00 vs. PDB, and a corresponding [j1110 average of + 17.9 ± 2.50/00 vs. SMOW. With the [j13C values of the rare intercalations of sedimentary limestones and dolomites lying in the normal range (- 0.2 ± 0.30/00 vs. PDB), the igneous carbonate constituents are :mlikely to be of sedimentary pedigree, but rather represent genuinely "hypogenic" material derived from primary magmatic sources.