黑龙江科洛河金矿区闪长岩脉年龄、地球化学特征及找矿意义OA

The Keluohe gold deposit is located on the eastern margin of the Xing'an block,on the Nenjiang-Heihe gold metallogenic belt,which is rich in gold mineral resources.To further determine the metallogenic age and tectonic setting of the Keluohe gold mining area,and provide guidance for regional mineral exploration.Zircon U-Pb dat-ing and geochemical analysis were conducted on diorite,and the temporal and spatial relationship between dikes and gold orebodies was studied.The gold ore bodies are mainly hosted in the Devonian granite mylonite and oc-cur parallel to the diorite veins above and below the ore bodies,a small part of the gold(ore)bodies is hosted in the diorite veins Zircon U-Pb dating reveals that the diorite was formed at(113±1.4)Ma.Geochemical analysis of the diorite veins shows that w(SiO2)=49.81％～56.11％,w(Al2O3)=1 6.16％～1 7.74％,w(MgO)=2.08％～6.70％,w(Na2O+K2O)=5.04％～7.18％,Na2O/K2O=2.1～2.6,Mg#=38～58,A/CNK=0.72～0.95(Conclusions).The diorite be-longs to the subaluminous high-potassium calc-alkaline series.The rocks are enriched in light rare earth elements and large ion lithophile elements such as K,Ba and Sr,and depleted in heavy rare earth elements and high field strength elements such as Ta,P,Hf and Ti.This indicates that the diorite magma originated from the enriched lithospheric mantle modified by subduction fluids.During the ascent of the magma,it was subjected to limited contamination by the lower crustal materials.The diorite veins were formed in the tectonic setting of the subduc-tion and delamination of the ancient Pacific plate.The diorite veins,which are closely associated with the gold ore bodies in space and time,are important mineral exploration indicators in the region.