نویسندگان
1 گروه زمین شناسی، دانشگاه پیام نور، تهران، ایران
2 گروه زمین شناسی، دانشکده علوم، دانشگاه اصفهان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The Dehshir and Nain ophiolites, located in the southwestern Yazd and northeastern Isfahan, respectively, are part of the ophiolite belts of Central Iran. These ophiolites are composed of various lithological units, including harzburgite, serpentinite, gabbro, plagiogranite, gabbroic dikes, diabase, and basalt. The occurrence of hydrothermal alteration and the influence of CO2-bearing fluids under suitable physicochemical and thermodynamic conditions in these regions have led to the formation of listwaenite, primarily composed of dolomite, magnesite, calcite, remnants of serpentine, chromite, and quartz. In these regions, carbonation is closely linked to listwaenitization. The origin of these veins is associated with the continuation of the regular listwaenitization reactions. Among the textures found in the listwaenite, the preserved schistosity texture in the carbonated serpentinites is notable, where along the schistosity, gradual infiltration and development of carbonates can be observed. In the studied areas, serpentinization of ultramafic rocks can provide sufficient magnesium for hydrothermal dolomitization. Elevated concentrations of iron and manganese in the dolomites may result from reducing conditions during alteration by hydrothermal fluids. All the dolomite samples show enrichment in LREEs relative to HREEs. The high concentration of REEs indicates a significant accumulation of these elements in the dolomitizing fluids and may also be a result of alteration and listwaenitization, with REEs leaching from the primary rock into the dolomitizing fluids. The fluid inclusions studied in both regions suggest the involvement of medium to high salinity and moderate homogenization temperatures fluids in the formation of the dolomites.
کلیدواژهها [English]
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