Document Type : Original Research Paper
Authors
1 Geological Survey of Iran,Tehran, Iran.
2 Tarbiat- Moalem University, Science faculty, Tehran, Iran.
3 Itok Engineering Company, Tehran, Iran.
Abstract
Mehdiabad Zn-Pb-Ba deposit is located 110 km south-east of Yazd, in the Central Iran structural zone. The stratigraphic succession consists of three sedimentary formations of lower Creataceous age. The Sangestan formation, the lowest unit of shale and siltstone with calcarenitic interbeded layers. This unit is overlain by ankeritic massive dolomite and dolomitic limestone of Taft formation. The Abkouh formation at the top is composed of cherty or clayey limestone with conglomeritic intercalation, lenses of massive reef limestone and calcareous shale. The structure of ore body shows a half-graben with a vast N-S syn form being complicated by the presence of poly phase faults. The main normal fault is Tappeh Siah fault, suggested to be active during and after the period of sedimentation. Major minerals are sphalerite and galena with minor pyrite, chalchopyrite in sulfide zone, smithzonite, hydrozincite, hemimorphite and cerussite in oxide zone. Mineralization occurs in stratiform-lenticular orebodies and concordant with host rocks. Also ore bodies showing laminated, disseminated, open space filling, karst filling, colloform and botryoidal textures.
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