Magmatic zircons from I-, S- and A-type granitoids in Tibet: Trace element characteristics and their application to detrital zircon provenance study

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• 作者：Qing Wang^a ; ^b ; ^{qing726@126.com} ; Di-Cheng Zhu^a ; ^b ; ^{dchengzhu@163.com} ; Zhi-Dan Zhao^a ; ^b ; Qi Guan^a ; ^b ; ^c ; Xiao-Qian Zhang^a ; ^b ; Qing-Lin Sui^a ; ^b ; Zhao-Chu Hu^d ; ^e ; Xuan-Xue Mo^a ; ^b
• 关键词：Zircon trace element ; Genetic types of granitoids ; Detrital zircon ; Nature of magmatic activity ; Paleogeographic reconstruction
• 刊名：Journal of Asian Earth Sciences
• 出版年：2012
• 期刊代码：40_13679120
• 类别：ear
• 出版时间：7 July, 2012
• 卷：53
• 期：Complete
• 页码：59-66
• 文件大小：813 K

摘要

This study reports a dataset of 21 trace elements of magmatic zircons from typical I-type (93 analyses) and S-type (73 analyses) granitoids from the Lhasa and Himalayan terranes, southern Tibet, and A-type granitoids (21 analyses) from the Songpan-Ganzi terrane, eastern Tibet. Our results indicate that magmatic zircons from the I-type granitoids are characterized by relatively lower Pb concentrations and higher (Nb/Pb)_N ratios, distinct from those of the S-type granitoids that reveal higher Pb, lower (Nb/Pb)_N and significant Eu negative anomalies (Eu/Eu^* 猢?#xA0;0.3); while these values are transitional in zircons from the A-type granitoids. Such differences, most likely governed by compositional variations in the host magmas, are considered as a useful tool, in addition to U-Pb and Hf isotopes, for tracing the source provenance of detrital zircons. Consequently, the trace element compositions of detrital zircons with a diagnostic age peak (鈭?170 Ma) from the Lhasa Terrane indicate the presence of coeval S-type magmatism in their source region. This study exemplifies the usefulness of zircon trace element geochemistry in investigating sedimentary source provenance and paleogeographic reconstruction.