中国地质Issue(4)：1092-1107,16.
内蒙古额仁陶勒盖地区侵入岩LA-ICP-MS锆石U-Pb年龄及地球化学特征
Zircon LA-ICP-MS U-Pb ages and geochemical features of intrusions in Erentaolegai area of Inner Mongolia
摘要
Abstract
The Erentaolegai silver deposit is a large epithermal silver deposit in Inner Mongolia. In this paper, chronologic and geochemical research were carried out on such intrusions as quartz porphyry, quartz monzonite, biotite syenogranite and fine-grained granite in the ore district. The zircon LA-ICP-MS U-Pb dating results show that the zircon U-Pb ages of the four intrusion samples are (285.4±1.9) Ma, (294.3±0.6) Ma, (287.0±1.2) Ma and (243.9±1.6) Ma respectively, which shows that the intrusions in the ore district were formed in the two periods of Late Hercynian and Indosinian. The age of the first three samples show that they were formed by magmatic evolution in the Late Hercynian period, and their geochemical features show the depletion of large ion incompatible elements such as Ba, Nb, Sr, Zr and Ti, the remarkable enrichment of K and the depletion of Ta, with weak negative Eu anomalies, and exhibit arc granite characteristics in (Y+Nb)-Rb and Yb-Ta tectonic environment discrimination diagrams for granitic rock and peraluminous S type granite, which suggests that they were formed in a tectonic environment of syn-collison in combination with the regional tectonic evolution. The zircon U-Pb age of the fine-grained granite is ( 243.9 ± 1.6 ) Ma, suggesting that it was formed by magmatic evolution in the Indosinian period;in addition, its geochemical features show the depletion of large ion incompatible elements such as Ba, Nb, Sr, Ti, Zr and Ti, the remarkable enrichment of K and the loss of Ta, with weak negative Eu anomalies, and has arc granite characteristics in (Y+Nb)-Rb and Yb-Ta tectonic environment discrimination diagrams for granitic rock and peraluminous S type granite, which implies that it was formed in a tectonic environment of volcanic arc in conjunction with the regional tectonic evolution. According to previous studies, the wall rock of the ore district is Tamulangou volcanic rock formed in the Middle Jurassic, and its 40Ar-39Ar isochron age is (162.6±0.7) Ma, which shows that there is no genetic relationship between the intrusion and the deposit.关键词
侵入岩/锆石U-Pb/LA-ICP-MS/地球化学/构造背景/额仁陶勒盖地区/内蒙古Key words
intrusion/zircon U-Pb/LA-ICP-MS/geochemistry/tectonic setting/Erentaolegai ore district/Inner Mongolia分类
天文与地球科学引用本文复制引用
田京,李进文,王润和,刘文,向安平,康永建,郭志军,董旭舟..内蒙古额仁陶勒盖地区侵入岩LA-ICP-MS锆石U-Pb年龄及地球化学特征[J].中国地质,2014,(4):1092-1107,16.基金项目
科技部973项目（2013CB428805）和中国地质调查局地质调查项目（1212011085260、科[2013]01-042-003）联合资助。 （）
