Economic Geology

A massive pyrite-pyrrhotite deposit is structurally localized by a steeply plunging anticline at Saladipura in the southern part of the Khetri copper belt. Sulfides are re-stricted mainly to amphibolites and along their contacts with the schists, carbon phyllites, marbles, and quartzitic rocks. Amphibolites occur at the core of the anticline. The minerals of the ore body include idiomorphic pyrite, arsenopyrite, pyrrhotite, sphalerite, chalcopyrite, magnetite, hematite, ilmenite, and rutile; sulfides are arranged in order of their paragenetic sequence. Wall rocks are various assemblages of amphibolites, which before the onset of mineralization, consisted of hornblende, actinolite, plagioclase, epidote, sphene, ilmenite and magnetite in varying proportions. With intensification of mineral-ization and crystallization of iron-rich sulfides, the iron-rich silicates have been depleted of iron resulting in the development of colorless tremolite, iron-poor actinolite and oxyactinolite. As a result of chlorine metasomatism the plagioclase and part of hornblende have been converted into scapolite. Pale-colored biotite, phlogopite and ferrimuscovite are associated with sulfides rather than dark-colored biotite. Very late alteration products include chlorite, sericite-muscovite, biotite and clay minerals. These alteration products and their distinctive association with sulfides suggest that Fe of pyrite and pyrrhotite has been derived from the preexisting iron-rich silicates and oxides