Geological Characteristics And Origin Of IOCG Ore Deposits Dong Junggar

The Lanshankou IOCG deposit is located in eastern the Altai southern margin, Qinghe county, Xinjiang, The geotectonic position is in the contact region of Siberia Plate and the Kazakistan-Junggar Plate, the geologic structure is complex, the magmatic activity is frequent, the mineral resource is rich. At present, this ore deposit is the first one which most has the prospecting potential IOCG ore deposit. Writer has been undergoing in looking for minerals in this area for a long time. Through the analysis of the regional geologic background in Eastem Junggar and the geologic exploration Practice of looking for mineral deposit and the research of the characteristics of large-middle scale Fe-Cu-Au deposits, some main achievements and knowledge are as follows:① According to the analysis of regional geologic feature and mineralization feature, a middle scale Fe-Cu-Au deposit was discovered in Lanshankou. Through geologic exploration, the geologic feature and mineralization feature of mineral district was confirmed. Some new opinions of mineral- forming mechanism, mineral-forming process was put forward, which showed that the mineralization took place in the embryonic stage of fracture-forming process and the mineral-forming solution took part in the formation of mineral-hosting structure. The research shows that the genetic type of mineral deposit is post-magmatic hydrothermal deposit, which is related to the crust-mantle type magma.② According to the research of regional stratum and structure and igneous rock feature combining with the theory of Plate tectonics, a close relationship between the geologic evolution and plate movement in the research area was put forward, the geologic evolution history of regional area is deduced preliminary.③ The geologic mineralization and deposit geochemistry characteristics of 3 IOCG deposits in the research areas restudied, and the genetic types of these mineral deposits is discussed also.④ Through the research of regional ore-forming geologic background and mineral deposit geologic feature of large-middle scale Fe-Cu-Au deposits, the source of ore-forming materials of Fe-Cu-Au is discussed, which showed that the Fe-Cu-Au mainly came from mantle. Mineralization had a close relationship with Caledonian period structure-magma action.⑤ This article has defined late Paleozoic Era regional tectonic setting and mineralization environment through analyzing the regional geology research results of the southern margin of Altay, strata characteristic, tectogenesis, magma event and so on. This ore deposit take Middle Devonian special rift valley on southern margin of Altaya background. The mineralization occurs in diorite(diorite porphyry)and nearby wall rock which intrude the Middle Devonian basalt.⑥ Through analysis predecessors data, the structure circumstances of volcanism and the genetic types of volcanic magma is discussed. Volcanism took Place in the back ground of Junggar Plate subduction to Kazakh Plate. Original volcanic magma came from upper mantle partmelt.⑦ The Laoshankou deposit metallogenetic epoch should be the Middle Devonian later period(376.9±2.2Ma). The mining area has two diagenesis mineralization event at least, it formed the layered whole-rock mineralization body first, later, the magma and the fluid activity occurred has superimposed the mineralization once again because of the tectonic thermal event, formed the copper high-grade orebody.