LA-ICP-MS Zircon U-Pb Age and Hf Isotope Composition of the Babaoshan Granite Porphyries in Lushi County, Henan Province
详细信息
- 责任者：Zeng Lingjun (Key Laboratory for Mineralogy and Metallogeny ; CAS ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Xing Yucai
- 刊名：Geotectonica et Metallogenia
- 出版年：2013
- 卷期：37(1)
- 关键词：花岗斑岩 ; granite porphyry ; 铀—铅计时 ; U-Pb dating ; 铪同位素 ; hafnium isotopes ; 河南 ; Henan Province
- 页码：p.65-77
- 图表：illus., 4 tables, 44 refs.
- 分类号：0801
- issnNo：ISSN1001-1552
- isbnNo：CN44-1595/P
摘要
The Babaoshan granite intrusion in Lushi county, Henan province, is tectonically located in the southern margin of North China Craton, on the western part of East Qinling orogen. The granite intrusion occurs as circular column which might have been the neck of volcanic edifice; while the associated iron ore deposit with accompanying Cu-Mo-Pb-Zn mineralization makes it a unique target for metallogenetic investigation in East Qinling area. The Babaoshan granite intrusion is a zoned granitic stock consisting of syenogranite porphyry in the outer zone and biotite monzogranite porphyry in the inner zone. LA-ICP-MS zircon U-Pb determination indicates that the syenogranite porphyry and biotite monzogranite porphyry are roughly coeval, formed at (146.6±1.6) Ma and (145.9±1.9) Ma, respectively. Zircon Hf isotope compositions of the syenogranite porphyry and biotite monzogranite porphyry are proximately identical, with εHf(t) values vary in ranges of -27.55~-20.71 and -27.30~-21.90, with Hf crustal model ages(tDM2) of 1.80~2.93 Ga and 2.03~2.92 Ga, respectively, indicative of crustal origin. Considering the tectonic evolution and geochemical characteristics of the granite as well as other Mesozoic granites in the southern margin of North China Craton, we suggest that the Babaoshan granite along with other Mesozoic granites was most likely derived from partial melting of subducted crust of Yangtze Craton, and possibly with minor involvement of the Taihua Group and Xiong’er Group under extensional tectonic regime following depression of the subduction-collision between the Yangtze and North China cratons.
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