Zircon LA-ICPMS U-Pb dating and geochemical characteristics of Huangshaping granite in southeast Hunan province, China.
Zircon LA-ICPMS U-Pb dating and geochemical characteristics of Huangshaping granite in southeast Hunan province, China.
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作者：
Yao Jun
南岭花岗岩带中部有千里山、骑田岭花岗岩和水口山、铜山岭、宝山花岗闪长岩体两种类型。黄沙坪花岗岩具有高SiO2、高K2 O、高K2 O/Na 2 O比值、高Rb、Th、U、Ta、Nb丰度和低Ba、Sr、P、Eu、Ti等特征，与前花岗岩相近。球粒陨石标准化稀土配分模式显示出强烈的负Eu异常。黄沙坪花岗岩的年代为161年。6 1. 1 Ma，与千里山（162。55±3。骑田岭花岗岩（161± 2 Ma）。这些年龄表明湘东南乃至整个南岭地区燕山期花岗岩有一个主要侵位期。黄沙坪花岗岩与千里山、骑田岭花岗岩具有相似的地球化学和年代学特征。它们是同一类型的花岗岩。它们的成岩作用与印支期造山作用后岩石圈伸展作用有关，是地壳物质部分熔融的产物。这与水口山、铜山岭、宝山等地的花岗闪长岩体不同。
There are two types granitoid in the middle of Nanling granitoid zone, including Qianlishan and Qitianling granites and Shuikoushan, Tongshanling and Baoshan granodiorite intrusions. The Huangshaping granite, which is close to the former granites, is characterized by higher values of SiO2 and K2O, higher ratio of K2O/Na2O, high abundances of Rb, Th, U, Ta and Nb, but lower contents of Ba, Sr, P, Eu and Ti. Chondrite-normalized REE patterns show strong negative Eu anomalies. The Huangshaping granite is dated 161. 6 1. 1 Ma by zircon LA-ICPMS U-Pb method, which is in accordance with ages of the Qianlishan(162. 55±3. 25Ma) and Qitianling (161±2Ma) granites. These ages imply a major emplacement period of the Yanshanian granites in southeast Hunan province as well as the whole Nanling Range area. In this study, the geochemical and geochronological characteristics are similar between Huangshaping granite and the Qianlishan and Qitianling granites. They are the same type granitoid. Their lithogenesis was related to the lithospheric extension after the Indosinian Orogenesis, and formed from partial melting of the crust material. All this are different from granodiorite intrusions in Shuikoushan, Tongshanling and Baoshan.