Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Effects of metamorphism on the Zurabad volcanogenic massive sulfide deposit in Khoy region

Authors
Zahra Ghodrati
Alijan Aftabi
Department of Geology, Faculty of Sciences, Shahid Bahonar University, Kerman, Iran
Abstract
Volcanogenic massive sulfide mineralization occurred within metabasaltic rocks in the Zurabad area. The rocks have been metamorphosed to greenschist facies. Mineralization in the metabasaltic rocks, metamorphism of these rocks and the effects of metamorphism on the sulfide lenses are new discoveries in the area and haven't been noticed previously. This paper documents the effects of metamorphism on the sulfide minerals and post-metamorphic processes on the sulfide mineralization. Mineralization occurs as sulfide lenses and gossans. In addition, sulfide mineralization is observed as disseminated, veins and layers. Sulfide minerals are: pyrite, pyrrhotite, chalcopyrite, sphalerite, covellite and marcasite. The primary oxide minerals are ilmenite and magnetite. The main silicate minerals are actinolite, chlorite, epidote, albite and quartz. Chlorite and actinolite indicate regional metamorphic foliation. The presence of porphyroblastic and granoblastic textures, folding of layers and veinlets, foliation of sulfides, annealing and growth of subgrains, suture and sliding rims in porphyroblast suture and cataclastic texture, all show evidence of dynamic-regional metamorphism. Regional metamorphism and dehydration reactions affected the area, and in this stage chlorite, epidote, calcite, quartz and sulfide veins were formed. Oxidation and supergene processes formed colloform, birds eye pyrite. Chalcopyrite and pyrhotite were converted to pyrite, marcasite and Fe-oxides. Based on the textural and mineralogical studies, mineralization in the Zurabad area is metamorphosed volcanogenic massive sulfide of Cyprus- type with enrichment of primary pyrhotite. The temperature of mineralization is estimated from sphalerite geothermometry to be about240° c.
Keywords
Metamorphism, massive sulfide deposit, Zurabad

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 7, 27-28
Spring & Summer 1999, vol. 7, No. 27-28
Summer 1999
Pages 54-63