quartz porphyry
1.Isotopic Chronological study shows that the fluid inclusion Rb-Sr isochron age (346±30Ma) of mineralized quartz veins is consistent with zircon U-Pb age (340Ma-360Ma) of quartz porphyry in test errors, showing that diagenetic and mineralization events happened during Early Carboniferous to Late Devonian and the mineralization is temporospatially related to the porphyry.
2.Isotopic chronological studies show that the fluid inclusion Rb-Sr isochron age(346±30 Ma)of mineralized quartz veins is consistent with the zircon U-Pb age(340～360 Ma)of quartz porphyry in test errors,suggesting that the rock-forming and ore-forming events occurred during Early Carboniferous to Late Devonian and the ore-forming process is related to the porphyry in time and space.
4.Rb-Sr isochron age of the stock is (127.9±1.6)Ma and ( 87 Sr/ 86 Sr)i ratio equals 0.7058, these data suggest that the quartz diorite porphyry was formed during late Yanshanian and the rockforming materials were originated from upper mantle, but has been contaminated by crustal materials during its ascent process.
5.The2 0 7Pb/ 2 0 6Pb age( 593Ma) of single zircon of quartz- syenite porphyry re- flects that the intrusion of subvolcanics is accompanied by capture of paleo- zircon of the basement rocks,im- plying that the Precambrian continental basement possibly exists below Aqishan- Yamansu volcanic island arc.
6.In the hinterland of South China, there are some Cretaceous A-type granitiods or alkaline intrusive rocks, e. g. , Huashan aegiriteaugite riebeckite granite in Anhui, Dayuancun aegiriteaugite arfvedsonite granite in Fujian, Ejinao nepheline sodalite syenite in Guangdong and Daheshan pyroxene quartz syenite porphyry and Sucun geode-like Kf-granite in Zhejiang.
7.Also, this study evaluates the Qinling metallogenic belt in terms of ore-forming potential and prospecting areas and concludes that prospective deposits are SEDEX and MVT types of Pb and Zn, vienlet-disseminated type and quartz vein altered type Au, porphyry type of Mo, W and Cu and epithermal Hg and Sb in the belt.
9.Dongtian gold deposit in the middle of Yunkai uplifted area, western Guangdong Province, is chosen as an example of those deposits. Comparative studies on the chondrite-normalized RE patterns and ΣRE, LRE/HRE, δ_(Eu), δ_(Ce), N_(La/Yb), and N_(La/Sm) of auriferous quartz veins, altered gneiss-type gold ores, Caledonian gneissic biotite granite, and Late Yanshanian granite porphyry were made.
