Geochemistry and origin of Mn-deposits in the Waziristan ophiolite complex, north Waziristan, Pakistan

摘要

The Waziristan ophiolite complex is located along the western margin of the Indian plate in northwestern Pakistan. The Mn-deposits in the Saidgi and Shuidar areas are part of this ophiolite complex. These deposits, both banded and massive in nature, are hosted by metachert and are generally overlying metavolcanics. Braunite and cryptocrystalline quartz are the main constituents of the manganese ores in both areas. Hematite occurs in the Shuidar deposits as a minor phase. Metacherts are microcrystalline aggregates of microcrystalline quartz, chalcedony, and lesser hematite. Chemically, the studied Mn-deposits and associated metacherts are very similar to those formed by submarine hydrothermal effusive processes. The deposits originated along sea-floor spreading centers (mid-ocean ridges) within the Neo-Tethys Ocean and were later obducted as part of the Waziristan ophiolite complex.