TY - JOUR
T1 - Crustally-derived granites in the Panzhihua region, SW China
T2 - Implications for felsic magmatism in the Emeishan large igneous province
AU - Shellnutt, J. Gregory
AU - Jahn, Bor Ming
AU - Zhou, Mei Fu
N1 - Funding Information:
We thank G.N. Eby, J.D. Greenough and H.A. Sandeman for their constructive reviews and Drs. G.F. Zellmer and T.-F Yui for their comments on an earlier version of this manuscript. The authors would like to thank Professor Ma Yuxiao and Mr. Zhao Hao both from Chengdu University of Science and Technology for their field support and Mr. Liang Qi and Ms. Xiao Fu for their analytical support at the University of Hong Kong. This study is supported by a 973 matching grant from HKU and Academia Sinica post-doctoral fellowship to JGS.
PY - 2011/4
Y1 - 2011/4
N2 - 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.
AB - 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.
KW - Aluminum saturation index
KW - Crustal melting
KW - Emeishan large igneous province
KW - Granite
KW - Late Permian
KW - Zr saturation thermometry
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U2 - 10.1016/j.lithos.2010.10.016
DO - 10.1016/j.lithos.2010.10.016
M3 - Article
AN - SCOPUS:79952536910
SN - 0024-4937
VL - 123
SP - 145
EP - 157
JO - Lithos
JF - Lithos
IS - 1-4
ER -