The Petrogenic age of Narigongma Granitic Diorite-porphyry in the Northern Part of the Sanjiang Region and Its Geological Implications

The Narigongma porphery molybdenite copper deposit related to intrusive rocks was discovered recently in the northern part of the Sanjiang Region.U-Pb dating shows that the formation age of Narigongma granodiorite porphyry is 41.44±0.23 Ma,belonging to early Himalayan period.Metallogenic ages of the Narigongma porphery molybdenite copper deposit are mainly in the range of 40.8±0.4 Ma～40.86±0.85 Ma.During multiperiodic hydrothermal activities and multistage ore-forming processes,the metallogenetic hydrothermal solution was provided by Narigongma granitite porphyry(41.53±0.24 Ma),Narigongma granite diorite-porphyry(41.44±0.23 Ma) and Narigongma plagioclase porphyry(41.00±0.18 Ma).Due to occurrence of many intermediate-acid mass,the age of these intrusive bodies provide evidence for collision function between India plate and Eurasian plate in 65～45 Ma,which has theoretical and practical meaning to forecast of porphyry copper-molybdenum deposit in the region.