Two types of granitic intrusives occur in the lower Paleozoic strata in north Qilian. One is the hornblende- bearing granitic body in Jingzichuan, characterized by the REE total of 90×10-6-106×10-6, LREE/HRE...Two types of granitic intrusives occur in the lower Paleozoic strata in north Qilian. One is the hornblende- bearing granitic body in Jingzichuan, characterized by the REE total of 90×10-6-106×10-6, LREE/HREE ratio of less than 8 (ranging from 6.9 to 7.8) and zircon SHRIMP age of 464 Ma. These intrusives have island-arc affinity. The other is biotite-bearing granitic body in Huangyanghe with the REE total of 214×10-6-250×10-6, LREE/HREE ratio of more than 8 (ranging from 8.2 to 9.7) and zircon LA-ICP-MS age of 383 Ma. They were tectonically intruded in a post-collisional or within-plate environment.展开更多
The Yematan batholith crops out over 120 km2 in the North Qaidam ultrahigh pressure (UHP) metamorphic belt. It consists of granodiorite, monzogranite and biotite granite and forms an irregular intrusion into Neoproter...The Yematan batholith crops out over 120 km2 in the North Qaidam ultrahigh pressure (UHP) metamorphic belt. It consists of granodiorite, monzogranite and biotite granite and forms an irregular intrusion into Neoproterozoic gneiss that has undergone Caledonian UHP metamorphism. Zircons from the Yematan granodiorite yield a SHRIMP U-Pb age of 397? Ma. These granitic rocks have geochemi- cal characteristics intermediate between I- and S-type gran- ites, and are post-collisional. We suggest that the Yematan granitic rocks were formed during the last exhumation event of the North Qaidam UHP belt.展开更多
基金the NationalNatural Science Foundation of China(Nos.40472034 ,49732070)Chinese National Key Project for Basic Research(2003CB716500)+1 种基金National 973 Project(G1988040800) China Geological Survey Project(200313000058).
文摘Two types of granitic intrusives occur in the lower Paleozoic strata in north Qilian. One is the hornblende- bearing granitic body in Jingzichuan, characterized by the REE total of 90×10-6-106×10-6, LREE/HREE ratio of less than 8 (ranging from 6.9 to 7.8) and zircon SHRIMP age of 464 Ma. These intrusives have island-arc affinity. The other is biotite-bearing granitic body in Huangyanghe with the REE total of 214×10-6-250×10-6, LREE/HREE ratio of more than 8 (ranging from 8.2 to 9.7) and zircon LA-ICP-MS age of 383 Ma. They were tectonically intruded in a post-collisional or within-plate environment.
文摘The Yematan batholith crops out over 120 km2 in the North Qaidam ultrahigh pressure (UHP) metamorphic belt. It consists of granodiorite, monzogranite and biotite granite and forms an irregular intrusion into Neoproterozoic gneiss that has undergone Caledonian UHP metamorphism. Zircons from the Yematan granodiorite yield a SHRIMP U-Pb age of 397? Ma. These granitic rocks have geochemi- cal characteristics intermediate between I- and S-type gran- ites, and are post-collisional. We suggest that the Yematan granitic rocks were formed during the last exhumation event of the North Qaidam UHP belt.
