Sulfur Isotope Geothermometry from the High Grade Metamorphosed Sulfide Deposit at Mamandur, Tamil Nadu

Sulfur isotope geothermometric data obtained from the limited study of coexisting sphalerite-galena pair in the high grade metamorphosed Zn-Pb(-Cu) deposit at Mamandur, furnish a wide range of values, from 870° C to 255° C. While the T_max closely matches with that from silicate geothermometry of adjacent rocks, some other data sets suggesting intermediate range of temperature are correlatable with a retrograde phase of regional metamorphism recorded in the silicates. The low temperatures however, are inconsistent with the silicate geothermometric data and may be taken to suggest resetting of equilibrium in the sulfide pair at lower temperatures without affecting the silicate pairs, as these temperatures were lower than the closure temperature of Fe-Mg partitioning in the latter.