摘要
The granitoids-diroretic complex and associated volcanic suits of Malek Siah Kuh (eastern Iran) were examined by RS, XRD, XRF, AAS and ICP-MS methods. The Multispectral data were used for differentiating of lithological units, main alterations, structural trends, and hydrothermally altered minerals. Based on the results of remote sensing, field studies and petrographic data, the complex classified into three main groups: 1) mafic unit (gabbro-basalt), 2) intermediate rocks (diorite-andesite suite) and 3) felsic unit (granitoide rocks). The complex is characterized by high Al2O3 and Sr contents as well as high Sr/Y and La/Yb ratios, while low in Y and Yb contents. The geochemical characteristics of these rocks indicate that they are similar to adakite like rocks. The complex is high calc-alkaline to shoshonitic nature. The results indicated derivation from similar silicate melt source followed by differentiation and assimilation of crustal rocks. Based on set of petrological and geochemical relations, 3 distinct stages of mineralization process can be recognized. 1) It is differentiation during magma evolution as well as metal enrichment and subsolidus leaching by hot fluids. 2) It occurred by ascending of the gas-rich magma and release of S and As. 3) It was accompanied by hydrothermal activities leading to the generation of sulfidation and associated polymetallic (Cu, Au, Fe) mineralization.
The granitoids-diroretic complex and associated volcanic suits of Malek Siah Kuh (eastern Iran) were examined by RS, XRD, XRF, AAS and ICP-MS methods. The Multispectral data were used for differentiating of lithological units, main alterations, structural trends, and hydrothermally altered minerals. Based on the results of remote sensing, field studies and petrographic data, the complex classified into three main groups: 1) mafic unit (gabbro-basalt), 2) intermediate rocks (diorite-andesite suite) and 3) felsic unit (granitoide rocks). The complex is characterized by high Al2O3 and Sr contents as well as high Sr/Y and La/Yb ratios, while low in Y and Yb contents. The geochemical characteristics of these rocks indicate that they are similar to adakite like rocks. The complex is high calc-alkaline to shoshonitic nature. The results indicated derivation from similar silicate melt source followed by differentiation and assimilation of crustal rocks. Based on set of petrological and geochemical relations, 3 distinct stages of mineralization process can be recognized. 1) It is differentiation during magma evolution as well as metal enrichment and subsolidus leaching by hot fluids. 2) It occurred by ascending of the gas-rich magma and release of S and As. 3) It was accompanied by hydrothermal activities leading to the generation of sulfidation and associated polymetallic (Cu, Au, Fe) mineralization.
