| 集宁地区两类古元古代重熔花岗岩的锆石U-Pb年代学及岩石成因 |
| |
| 引用本文： | 常青松,王惠初,施建荣,任云伟.集宁地区两类古元古代重熔花岗岩的锆石U-Pb年代学及岩石成因[J].地球科学,2020,45(9):3258-3267. |
| |
| 作者姓名： | 常青松 王惠初 施建荣 任云伟 |
| |
| 作者单位： | 1.中国地质调查局天津地质调查中心, 天津 300170 |
| |
| 基金项目： | 中国地质调查局地质调查二级项目DD20160042中国地质调查局地质调查二级项目DD20190035 |
| |
| 摘 要： | 学术界对集宁-凉城地区的古元古代重熔型花岗岩成因一直持有不同的解释，本文对集宁土贵乌拉-隆盛庄一带两类重熔花岗岩进行了同位素年代学及地球化学研究.锆石LA-MC-ICP-MS U-Pb年代学结果显示，斑状石榴紫苏二长花岗质片麻岩具有1 954 Ma的侵位年龄及1 827 Ma的变质年龄，变质淡色石榴二长花岗岩具有1 956 Ma的侵位年龄.岩石地球化学特征显示斑状石榴紫苏二长花岗质片麻岩低硅、高镁铁，具有Eu负异常及Sr的相对亏损；变质淡色石榴二长花岗岩富硅、贫铁镁，强烈亏损Nb、Ta、Ti等高场强元素，富集K和Rb、Ba等亲石元素.二者形成时代相同，可能源自幔源岩浆底侵造成的重熔，斑状石榴紫苏二长花岗质片麻岩源岩为孔兹岩系沉积岩，混合了一定比例的幔源物质组分并经过分离结晶过程；变质淡色石榴二长花岗岩源岩主要为孔兹岩系沉积岩，较少受到幔源组分的影响.
|
| 关 键 词： | 重熔花岗岩 古元古代 锆石U-Pb年代学 地球化学 |
| 收稿时间： | 2020-04-02 |
Zircon U-Pb Chronology and Petrogenesis of Two Types of Remelting Granite in Jining Area |
| |
| Abstract: | The petrogenesis of Paleoproterozoic remelting granite in Jining-Liangcheng area has been interpreted differently in academia. Geochronologic and geochemical studies of two types of remelting granite are presented in this paper. Zircon LA-MC-ICP-MS U-Pb isotopic dating reveals that the porphyritic charnockites emplaced at 1 954 Ma and were metamorphosed at 1 827 Ma, and the meta-leucogranites emplaced at 1 956 Ma. The porphyritic charnockites are characterized by low Si contents, high Fe and Mg contents, with negative Eu anomalies and relative depletion of Sr. The meta-leucogranites have high content of Si and low contents of Fe and Mg, strong depletion in high filed-strength elements (HFSE, such as Nb, Ta and Ti) and enrichment in large iron lithophile elements (LILE, such as K, Rb and Ba). Both two types of granite were generated in the same period, from the remelting associated with mantle-source magma underplating. The source magma of the porphyritic charnockites was mixed with certain amount of mantle contribution during remelting of meta-sediments of khondalite series, before fractional crystallization. And the source magma of the meta-leucogranites was generated mainly from remelting of meta-sediments of khondalite series, with limited influence of mantle contribution. |
| |
| Keywords: | |
|
| 点击此处可从《地球科学》浏览原始摘要信息 |
|
点击此处可从《地球科学》下载全文 |
|
