地质通报2017，Vol.36Issue(7)：1118-1128,11.
秦祁结合部位宝鸡地区早泥盆世香泉A型正长花岗岩年龄、地球化学特征及其构造意义
Age and geochemical features of the Early Devonian Xiangquan A-type syenogranites from Baoji area at the conjunction of Qinling and Qilian Orogen and their tectonic significance
摘要
Abstract
Xiangquan syengranites are located in Baoji area at the conjunction of Qinling and Qilian Orogen, and their LA-ICP-MS zircon U-Pb geochronological and petrogeochemical studies were conducted in this paper. The resul ts show that the zircon 206Pb/238Pb weighted average age of Xiangquan syengranites is 410±5Ma (MSWD=0.20, n=18), indicating that the crystallization age of the syengranites is Early Devonian. Xiangquan syengranites are high in SiO2 (SiO2=69.63%~73.94%), K2O (K2O=4.24%~4.88%, K2O/Na2O=1.23~1.44), and TFe2O3 (TFe2O3=2.10%~3.70%, TFe2O3/MgO=3.88~6.84), but low in MgO (MgO=0.31%~0.94%) and P2O5(P2O5=0.08%~0.21%),belonging to high-K calc-alkaline series with metaluminous features. In addition, they are enriched in total REE (318×10-6~499×10-6), with obvious negative Eu anomaly (δEu=0.37~0.46). The trace elements show enrichement of Rb, Th, Zr, Sm and Ga (10000×Ga/Al=2.59~2.93), depletion of Ba, Nb, Ta and Sr, with the characteristics of A-type granites on the whole. Combined with regional data, the authors hold that the Xiangquan syenogranites were formed in a post-orogenic tectonic setting and derived from partially melted felsic crust under low pressures.关键词
香泉正长花岗岩/宝鸡地区/秦祁结合部位/造山后A型花岗岩/早泥盆世Key words
Xiangquan syengranites/Baoji area/conjunction of Qinling and Qilian Orogen/post-orogenic A-type granites/Early Devonian分类
天文与地球科学引用本文复制引用
徐通,陈清敏,郭岐明,张拴厚,毛友亮,王强..秦祁结合部位宝鸡地区早泥盆世香泉A型正长花岗岩年龄、地球化学特征及其构造意义[J].地质通报,2017,36(7):1118-1128,11.基金项目
陕西省公益性地勘专项项目《陕西秦岭造山带中生代构造体制与成矿作用研究》(编号:20130301) （编号:20130301）
