Document Type : Original Research Paper
Authors
1 Master of Science, Department of Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran.
2 Associate Professor, Department of Geology, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, Iran.
3 Assistant Professor, Faculty of Earth Sciences, Shahrood University of Technology, Shahrood, Iran.
Abstract
The Chah Gaz Zn-Pb-Cu volcanogenic massive sulfide (VMS) deposit is a polydeformed, polymetamorphosed ore body in southern part of the Sanandaj-Sirjan zone. The ore bodies are comprised predominantly of stratiform, tabular and lenticular massive sulfide lenses and are elongated in 0600-0700 orientation. The host rocks and massive sulfides have been complexly deformed during three deformation stages (D1, D2, D3) and two associated episodes of green schist facies metamorphism (M1, M2) that all events occurred after middle Jurassic. The earliest structural elements in the mine area are bedding and continuous foliation (S1) that are preserved in the host rocks; include phyllites, slates and schists. F1 folds have not been identified in the ore bodies, Although they do recognized as shallowly to moderately plunging to NW and isoclinal folds within the Chah Gaz area. Geometry of ore bodies was mainly controlled by D2 structures (include folds and foliations). F2 plunge shallowly to NE or SW. F2 are close to open and their axial planes dip steeply to S and N. Ore bodies are commonly transposed from S0-S1 and show rearrangement parallel to axial planar foliation (AS2) and composite foliation (ST2). ST2 is vertical and strikes NE-SW. Sulfide minerals in the ore bodies have undergone extensive deformation, remobilization and dynamic recrystallisation during D2 tectono-thermal stage. D3 structures are locally controller of ore bodies and include folds and shear zones.
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