| There has been a great deal of controversy about the tectonic evolution of East Tianshan.The author is inclined to the following view:the supercontinent named Rodinia was cracked to form a complex ocean and land collision system in the Precambrian.The North Tianshan Ocean began to subduct from the Ordovician to the Permian.After then,it entered the collision orogenic phase.The Yuhai porphy deposit was formed during this period.Yuhai porphyry deposit is located in the Jueluotage metallogenic belt in the East Tianshan,and belongs to the East extension of the Tuwu-Yandong porphyry metallogenic belt.The special geographical location and geological background of the Yuhai mining area make it possible to become a new large metal deposit enrichment area.Through field investigation and laboratory analysis,combined with regional geological background,geological characteristics,rock characteristics and geochemical characteristics of rock.The results are as follows:1.The geological characteristics of the Yu Hai deposit are very similar to those of the typical porphyry deposits.The mineralization type is mainly veined disseminated and sparse disseminated.2.Through the geological features of the deposit and the geochronology of the deposit,we conclude that the intrusive rock of yuhai porphyry deposit is a set of diorite–granodiorite.The zircon U-Pb dating of the diorite–granodiorite is441.6±4.1Ma.3.The diorite and granodiorite are characterized by high Si O2?Al2O3?MgO and low K2O+Na2O,TiO2,P2O5,MnO.It belongs to a typical low potassium?pulla?series.The content of SiO2 in the rock is higher,K2O content is lower,and the range of Na2O/K2O change is 1.36-14.15.They are characterized by a strong LREE enrichment,moderate HREE depletion and slightly positive Eu anomalies that reflect clear subduction signatures.In addition,the Yuhai intrusions show pronounced depletions of Nb,Ta and Ti and enrichments of K,Rb and Pb,similar to those of most modern subduction-related plutonic rocks formed by the partial melting of subducted oceanic slabs.4.Combined with regional tectonic evolution,it is believed that the formation of the Yuhai deposit is related to the continuous subduction of the North Tianshan ocean.The late large-scale tectonic magmatism destroyed the early form and scale of the Yuhai deposit,which made the deposit present its present form.5.According to the characteristics of regional geophysics and geochemistry,the area of heavy and magnetic anomalies in the mining area is well fitted,and the anomalous band of Cu is extended from the north West to the west,and it is not closed to the West.Therefore,it is concluded that the prospecting prospect of the mining area to the west and the north is better. |
PDF Full Text Request