LA-ICP-MS Zircon U-Pb Dating and Its Geological Implications of Banzhusi Granitic Porphyry in Xiongershan of Western Henan Province

There are 121 endogenetic metal deposits and mineralizaion spots found in Xiongershan of western Henan province, which are distributed in the west of 112°E. On the east side of this longitude, however, no endogenetic metal mineralization has been found until now. So the longitude may have a great significance to the ore prospecting direction in this area. LA-ICP-MS zircon U-Pb dating is conducted on Banzhusi granitic porphyry, whose outcrop proportion takes up most of the area eastern of longitude 112. Values of 29 zircon measuring points from sample BZS01 are analyzed in total, and all of them are in concordance in the ²⁰⁷Pb/²³⁵U-²⁰⁶Pb/²³⁸U diagram, whose ²⁰⁶Pb/²³⁸U ages change between 124Ma and 138 Ma. The weighted average age of 28 analyzed spots is 129±1 Ma, suggesting that the ore body was formed in early Cretaceous. The research also indicates that Banzhusi rock mass is the product of lithosphere delamination, and its age falls into the time interval of extensive and intensive endogenetic mineralization in east Qinling orogenic belt. Samples from Banzhusi ore body have displayed abnormal enrichment in Au, Ag, Pb and Zn, from which it can be considered that Banzhusi ore body possesses endogenetic mineralization potential.