The Bangong Lake-Nujiang River metallogenic belt is located between the Qiangtang Block and Lhasa Block, and the Duolong ore concentration area is located in the western section of the Bangong Lake-Nujiang River metal...The Bangong Lake-Nujiang River metallogenic belt is located between the Qiangtang Block and Lhasa Block, and the Duolong ore concentration area is located in the western section of the Bangong Lake-Nujiang River metallogenic belt. Till now, several large and super large copper-gold deposits, such as Duobuza, Bolong, Dibaonamugang, Naruo and Rongna deposits have been discovered in this area, mainly porphyry copper-gold ones.展开更多
The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China.Its tectonic environment relevant to Early Cretaceous Cu–Au minerali...The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China.Its tectonic environment relevant to Early Cretaceous Cu–Au mineralization remains controversial.Here we report new whole-rock major and trace element,and Sr-Nd-Hf-Pb isotopic data for the newly discovered basalt in the Nadun area,Duolong mineral district,to decipher their genesis and further constrain the tectonic environment.A contemporaneous rhyolite sample interbedded with the basalt in the lower part of the volcanic section in the Nadun area yields an LA-ICP-MS zircon U–Pb age of 122.5±1.2 Ma.The basalt samples exhibit high-K calc-alkaline/shoshonite properties and are enriched in high field strength elements,e.g.,high Ti O_(2)(1.43–1.79 wt.%)and Nb(14.6–19.5 ppm)contents,with high Nb/La ratios(0.4–0.6),which are compositionally comparable to those of Nb-enriched arc basalts(NEABs).The(^(87) Sr/^(86) Sr)iratios of 0.7052 to 0.7056,negative eNd(t)(-0.7 to-0.2)and eHf(t)values(+6.0 to+6.5),and high(^(206) Pb/^(204)Pb)i,(^(207) Pb/^(204)Pb)i,(^(208) Pb/^(204)Pb)iand ratios(18.522 to 18.561,15.641 to 15.645 and 38.679 to 38.730,respectively)suggest that the Nadun NEABs are more enriched than those of the island arc basalts(IABs)in the area.The slightly enriched radiogenic isotopes for the Nadun NEABs indicate that the subducting sediments play an important role in the source.Furthermore,their high Nb,Ti,and Cu contents indicate that the source mantle wedge was metasomatized by slab melts.The Nadun NEAB and other coeval magmatic rocks in the Duolong mineral district,including adakite,OIB-like basalt,MORB-type basalt,A-type rhyolite,and common IAB,are typical rock assemblages of ridge subduction.We infer that the Duolong mineral district were formed by ridge subduction in the Early Cretaceous.展开更多
基金granted by the Geological Survey Program of China Geological Survey (Grant No.1212011086074 and 12120113036500)
文摘The Bangong Lake-Nujiang River metallogenic belt is located between the Qiangtang Block and Lhasa Block, and the Duolong ore concentration area is located in the western section of the Bangong Lake-Nujiang River metallogenic belt. Till now, several large and super large copper-gold deposits, such as Duobuza, Bolong, Dibaonamugang, Naruo and Rongna deposits have been discovered in this area, mainly porphyry copper-gold ones.
基金supported by the National Natural Science Foundation of China(Grant Nos.42002235,41803002)the National Key R&D Program of China(2016YFC0600408)+3 种基金the China Postdoctoral Science Foundation(Grant Nos.2019M652495,2018M642708)the Taishan Scholar Program of Shandong(ts201712075)the Ao Shan Talents Cultivation Program Supported by Qingdao National Laboratory for Marine Science and Technology(2017ASTCP-OS07)the Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.JCZX202026)。
文摘The Duolong mineral district in western Tibet is one of the largest porphyry Cu–Au deposit fields with significant metallogenic potential in China.Its tectonic environment relevant to Early Cretaceous Cu–Au mineralization remains controversial.Here we report new whole-rock major and trace element,and Sr-Nd-Hf-Pb isotopic data for the newly discovered basalt in the Nadun area,Duolong mineral district,to decipher their genesis and further constrain the tectonic environment.A contemporaneous rhyolite sample interbedded with the basalt in the lower part of the volcanic section in the Nadun area yields an LA-ICP-MS zircon U–Pb age of 122.5±1.2 Ma.The basalt samples exhibit high-K calc-alkaline/shoshonite properties and are enriched in high field strength elements,e.g.,high Ti O_(2)(1.43–1.79 wt.%)and Nb(14.6–19.5 ppm)contents,with high Nb/La ratios(0.4–0.6),which are compositionally comparable to those of Nb-enriched arc basalts(NEABs).The(^(87) Sr/^(86) Sr)iratios of 0.7052 to 0.7056,negative eNd(t)(-0.7 to-0.2)and eHf(t)values(+6.0 to+6.5),and high(^(206) Pb/^(204)Pb)i,(^(207) Pb/^(204)Pb)i,(^(208) Pb/^(204)Pb)iand ratios(18.522 to 18.561,15.641 to 15.645 and 38.679 to 38.730,respectively)suggest that the Nadun NEABs are more enriched than those of the island arc basalts(IABs)in the area.The slightly enriched radiogenic isotopes for the Nadun NEABs indicate that the subducting sediments play an important role in the source.Furthermore,their high Nb,Ti,and Cu contents indicate that the source mantle wedge was metasomatized by slab melts.The Nadun NEAB and other coeval magmatic rocks in the Duolong mineral district,including adakite,OIB-like basalt,MORB-type basalt,A-type rhyolite,and common IAB,are typical rock assemblages of ridge subduction.We infer that the Duolong mineral district were formed by ridge subduction in the Early Cretaceous.
