Metallogenetic Ages And Geochemical Characteristics Of Zhuxiling W-Ag Polymetallic Deposit In Ningguo City,Southern Anhui Province

Zhuxiling W-Ag polymetallic skarn deposit is the newly-discovered one which is associated with granitoid recently in the southern Anhui.On the basis of investigation of Zhuxiling ore deposit,geochemical characteristics of Zhuxiling granodiorite were studied,and modern isotope dating technique is applied in this paper.The main results obtained in this paper are as follows:Zhuxiling W-Ag polymetallic deposit is skarn-type deposit.Most orebodies occurred in the contacting zone between granodiorite and strata as well as limestones near the aforesaid contacting zone.The orebodies in quasi-lamellar-lens-like shap occurred paralley with wall rocks,and presented some characters of strata–bound deposit.There are granodiorite,granodiorite porphyry and granite porphyry occurtring in thethe mining area.What's more,granodiorite is main magma and main ore-hosting rock closely related to mineralization.Ore-hosting granodiorite is of high-K calc-alkaline series and classified as I type granite.The Sr-Nd isotopic compositions show that granodiorite-forming materials might be from a source region containing crustal and mantle components but mainly crustal components.We obtain two Re-Os model ages of molybdenite: 142.7 ± 2.1Ma and142.9 ± 2.1Ma,and the zircon LA-ICP MS U-Pb ages of zircon of granodiorite,granodiorite porphyry,granite porphyry are 139.8 ± 1.8Ma,140.2 ± 1.7Ma,143.3 ± 1.9Ma.These granitoid ages and metallogenic ages are almost consistent,suggesting they occurred at Early Cretaceous in late Yanshanian.Moreover,The rhenium values of molybdenite samples imply that their metallogenic materials are derived from mixture of crust and mantle materials.Through the comparison of regional magmatic rock and ore deposit study,large-scale magmatism and mineralization in the Middle and Lower Reaches of the Yangtze River Belt occurred at this time.Large-scale W-Sn magmatism and mineralization also happened in the South China meallogenic belt indicating that the Yangtze plate was in the magmatism–mineralization explosion period.Mineralogenetic epoch of southern Anhui is corresponding to the second stage for Mesozoic three large-scale mineralization in south China.