Characteristics and Geological Significance of C、O Isotopes of Calcite in the Yindonggou Pb-Zn-Ag Deposit,North Neixiang,Henan Province

The large Ag-Pb-Zn deposit in the northern Neixiang County,Henan Province,is found in the Erlangping Terrain,which is on the north side of the Zhu Xia fault in the North Qinling orogenic belt,and formed in deterioration volcano-sedimentary of the back-arc environment during the late Proterozoic-early Paleozoic.About 100 mineral veins were found as filling fault structures of the vertical orogenic belt or presenting layered and bedded single veins.We select calcite samples of Y1,Y6,Y10 and Z2 to test their C、O isotope.The results show that δ13C ranges from-5.45‰~-2.19‰ and δ18O ranges from 10.03‰~14.50‰,the C、O isotope of CO2 in ore fluid δ13C∑C ranges from 0.06‰~1.42‰,indicating that sulfur is mainly from the underthrusted slab metamorphically devolatilized when the Qinling Group underthrusted northward beneath the Erlangping Terrane along the Zhu-Xia fault.