岩石矿物学杂志2012，Vol.31Issue(5)：652-662,11.
扬子地台西缘淌塘花岗岩的地球化学特征及锆石U-Pb定年
Geochemistry and zircon U-Pb dating of Tangtang granite in the western margin of the Yangtze Platform
摘要
Abstract
The Tangtang granite occurs in the western rnargin of the Yangtze platform and mainly consists of plagioclase granite. In order to reveal the significance of its petrogenesis, the authors studied the SHRIMP U-Pb dating of zircon and geochemistry of the granite. Geochemical and petrologic data show that the Tangtang granite is characterized by high silicon (SiQ2 =72.70%~77.95% ), high alkali (ALK = 5.68% ~7.32% ) and per-aluminous nature (ASI = 1.41~1.78), the average of K2O/Na2O ratios is 1.18, and the content of CaO and MgO is very low. Thus, the granite is a typical high-K calc-alkaline S-type granite. It has low REE concentrations and obvious difference between LREE and HREE (LREE/HREE = 2.71~4.09), and its trace elements are different from those of the crust. SHRIMP U-Pb dating of the magmatic zircon yielded the age of 1 063.2 ± 6.9 Ma, which should be regarded as the formation age of the granite, and hence the granite was probably related to the Grenville orogenic event. Based on these geochemical characteristics, this paper deals with the petrogenesis of Tangtang granite. It is suggested that the granite was formed by partial melting of argillaceous rocks in the crust. The pattern of bimodel magmatic rocks and the Al2O3 - SiO2 diagram both indicate that the formation of Tangtang granite was closely related to the rift environment. The result is consistent with the tectonic setting of 1.0 Ga in the western margin of the Yangtze platform and also corresponds to the Rodinia supercontinent convergence.关键词
扬子地台西缘/化岗岩/SHRIMP锆石定年/Rodinia超大陆/淌塘Key words
western margin of the Yangtze platform/ granite/ SHRIMP U-Pb dating/ Rodinia supercontinent/Tangtang分类
天文与地球科学引用本文复制引用
王子正,周邦国,郭阳,杨斌,廖震文,王生伟..扬子地台西缘淌塘花岗岩的地球化学特征及锆石U-Pb定年[J].岩石矿物学杂志,2012,31(5):652-662,11.基金项目
中国地质调查局地质调查资助项目(1212010813066) （1212010813066）
