Crustally-derived granites in the Panzhihua region, SW China: Implications for felsic magmatism in the Emeishan large igneous province

J. Gregory Shellnutt*, Bor Ming Jahn, Mei Fu Zhou

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

62 引文 斯高帕斯(Scopus)

摘要

In the Panxi region of the Late Permian (~260Ma) Emeishan large igneous province (ELIP) there is a bimodal assemblage of mafic and felsic plutonic rocks. Most Emeishan granitic rocks were derived by differentiation of basaltic magmas (i.e. mantle-derived) or by mixing between crustal melts and primary basaltic magmas (i.e. hybrid). The Yingpanliangzi granitic pluton within the city of Panzhihua intrudes Sinian (~600Ma) marbles and is unlike the mantle-derived or hybrid granitic rocks. The SHRIMP zircon U-Pb ages of the Yingpanliangzi pluton range from 259±8Ma to 882±22Ma. Younger ages are found on the zircon rims whereas older ages are found within the cores. Field relationships and petrography indicate that the Yingpanliangzi pluton must be <600Ma, therefore the older zircons are interpreted to represent the protolith age whereas the younger analyses represent zircon re-crystallization during emplacement. The Yingpanliangzi granites are metaluminous and have negative Ta-NbPM anomalies, low εNd(260 Ma) values (-3.9 to -4.4), and high ISr (0.71074 to 0.71507) consistent with a crustal origin. The recognition of a crustally-derived pluton along with mantle-derived and mantle-crust hybrid plutons within the Panxi region of the ELIP is evidence for a complete spectrum of sources. As a consequence, the types of Panxi granitoids can be distinguished according to their ASI, Eu/Eu*, εNd(T), εHf(T), TZr(°C) and Nb-TaPM values. The diverse granitic magmatism during the evolution of the ELIP from ~260Ma to ~252Ma demonstrates the complexity of crustal growth associated with LIPs.

原文英語
頁(從 - 到)145-157
頁數13
期刊Lithos
123
發行號1-4
DOIs
出版狀態已發佈 - 2011 四月
對外發佈

ASJC Scopus subject areas

  • 地質學
  • 地球化學與岩石學

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