Magmatic events recorded in granitic gneisses from the Hatu area, eastern East Kunlun Orogen: Response to the assembly of Rodinia

作者：Chen, Youxin; Pei, Xianzhi^*; Li, Zuochen; Li, Ruibao; Liu, Chengjun; Wang, Meng

来源：Geological Journal, 2017, 52(S1): 403-418.

DOI：10.1002/gj.3006

• East Kunlun Orogen
• Hatu granitic gneisses
• Neoproterozoic
• supercontinent Rodinia
• syn-collision

A suite of granitic gneisses has been identified in the Hatu area, eastern segment of the East Kunlun Orogen. Zircon U-Pb dating of granitic gneisses indicates magmatic crystallization at 895.4 +/- 9.3Ma. However, some zircons yield a metamorphic age of 433.8 +/- 6.2Ma. When taken together, these data reveal that the Early Neoproterozoic granites experienced Early Paleozoic metamorphism. The granitic gneisses are characterized by high contents of SiO2, Al2O3, and K2O+Na2O and low concentrations of TiO2, MnO, and CaO. The petrochemical character (average A/CNK=1.09 and average A/NK=1.42) and the mineral assemblages suggest that the granites are of S type and peraluminous. The chondrite-normalized rare earth element patterns of the samples show enrichment of light rare earth elements ((La/Yb)(N)=13.84) and moderate negative Eu anomalies (Eu=0.60). The primitive-mantle-normalized trace element diagrams show an enrichment of Rb and Th and a depletion of Ta, Nb, Sr, P, and Ti. The granitic gneisses have features of crust-derived and typical continent-continent syn-collisional granites. All the above characteristics suggest that the Paleoproterozoic Baishahe Formation probably served as the source rocks and that the granitic gneisses were generated by partial melting of the metasedimentary material related to crustal thickening. They also reveal a collision between the micro-block in the Early Neoproterozoic in response to the assembly of the supercontinent Rodinia in East Kunlun.

• 出版日期2017-12
• 单位长安大学