| 甘肃北山前红泉地区斑状花岗闪长岩年代学、地球化学特征及其构造意义 |
| |
| 引用本文： | 杨镇熙,赵吉昌,荆德龙,赵青虎,张晶,樊新祥.甘肃北山前红泉地区斑状花岗闪长岩年代学、地球化学特征及其构造意义[J].矿物岩石地球化学通报,2021,40(1):228-241. |
| |
| 作者姓名： | 杨镇熙 赵吉昌 荆德龙 赵青虎 张晶 樊新祥 |
| |
| 作者单位： | 甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000;甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000;中国地质调查局西安地质调查中心,西安710054;甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000;甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000;甘肃省地质矿产勘查开发局第四地质矿产勘查院,甘肃酒泉735000 |
| |
| 基金项目： | 甘肃省基础地质调查项目;陕西省自然科学基础研究计划 |
| |
| 摘 要： | 为探讨甘肃北山造山带晚古生代-中生代的构造演化特征,对该区前红泉地区的斑状花岗闪长岩开展了年代学和地球化学研究。通过高精度的LA-ICP-MS锆石U-Pb测年,获得了该区斑状花岗闪长岩的加权平均年龄为(264.2±1.2) Ma、(249.3±1.1) Ma和(234.3±1.1) Ma,表明其为中二叠世-晚三叠世岩浆活动的产物。地球化学数据表明,岩体为准铝质、高钾钙碱性系列,主量元素表现为高硅(SiO2为64.03%~72.23%)、高铝(Al2O3为14.01%~16.60%)、富碱(Na2O+K2O为7.20%~8.36%)和低钙(CaO为1.87%~3.43%)、贫镁(MgO为0.55%~1.53%);轻稀土富集,轻重稀土分馏明显,具负Eu异常(δEu为0.56~0.87);微量元素富集强不相容元素Th、U和大离子亲石元素Rb、K,显著亏损高场强元素Nb、P、Ti,表现出I型花岗岩的特点。结合区域地质背景,认为北山洋盆在早二叠世已经闭合,中二叠世-晚三叠世北山南带处于后碰撞伸展的大地构造环境。
|
| 关 键 词： | 斑状花岗闪长岩 锆石U-PB定年 岩石地球化学 后碰撞 北山地区 |
Chronological and Geochemical Characteristics of the Porphyritic Granodiorite in the Qianhongquan Area,Beishan Region,Gansu Province,China and Their Tectonic Significances |
| |
| YANG Zhen-xi,ZHAO Ji-chang,JING De-long,ZHAO Qing-hu,ZHANG Jing,FAN Xin-xiang.Chronological and Geochemical Characteristics of the Porphyritic Granodiorite in the Qianhongquan Area,Beishan Region,Gansu Province,China and Their Tectonic Significances[J].Bulletin of Mineralogy Petrology and Geochemistry,2021,40(1):228-241. |
| |
| Authors: | YANG Zhen-xi ZHAO Ji-chang JING De-long ZHAO Qing-hu ZHANG Jing FAN Xin-xiang |
| |
| Institution: | (Fourth Institute of Gological and Mineral Exploration of Gansu Provincial Bureau of Geology and Mineral Resources,Jiuquan Gansu 735000,China;Xi'an Geological Survey Center of China Geological Survey,Xi'an 710054,China) |
| |
| Abstract: | In order to explore tectonic evolution characteristics of the Beishan orogenic belt in Gansu province during the Late Paleozoic to Mesozoic periods, a study on chronology and geochemistry of porphyritic granodiorites in the Qianhongquan area of the Beishan orogenic belt has been carried out in this paper. The high precision LA-ICP-MS zircon dating results show that porphyritic granodiorites in the Qianhongquan area have weighted average ages of(264.2±1.2) Ma,(249.3±1.1) Ma and(234.3±1.1) Ma, respectively, indicating that they are products of Middle Permian to Late Triassic magmatic movements. Geochemical data show that these rocks belong to metaluminous and high potassium calc-alkaline series with characteristics of high Si(SiO2 contents of 64.03%-72.23%), high Al(Al2O3 contents of 14.01%-16.60%), alkaline-rich(Na2O+K2O contents of 7.20%-8.36%), low Ca(CaO contents of 1.87%-3.43%), Mg-poor(MgO contents of 0.55%-1.53%), LREE-enriched, obvious fractionation of LREE and HREE, negative Eu anomalies(δEu values of 0.56-0.87), enriched strongly incompatible elements of Th, U and large ionophile elements of Rb and K, obviously depleted high field strength elements(HFSE) of Nb, P, and Ti, indicating that they have characteristics of the I-type granite. Combined with regional geological setting, it is believed that the Beishan oceanic basin could be closed in the Early Permian, whereas the southern part of the Beishan area was in a tectonic environment of post-collisional extension during the Middle Permian to Late Triassic periods. |
| |
| Keywords: | porphyritic granodiorite zircon U-Pb dating petrogeochemistry post-collision Beishan region |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
|
