河北平山英云闪长质片麻岩锆石SHRIMP年代学

河北平山英云闪长质片麻岩锆石SHRIMP年代学

杨崇辉1, 杜利林1, 万渝生1, 刘增校2

1. 中国地质科学院地质研究所，北京 100037; 2. 河北地质矿产调查研究所，河北廊坊 065000

收稿日期:2004-12-20 修回日期:2004-12-20 出版日期:2004-12-20 发布日期:2004-12-20

SHRIMP Zircon U-Pb Chronology of Tonalitic Gneiss in Banqiaogou Area, Pingshan County, Hebei Province

YANG Chong-hui1, DU Li-lin1, WAN Yu-sheng1, LIU Zeng-xiao2

1. Institute of Geology, CAGS, Beijing 100037, China; 2. Hefei Institute of Geology and Mineral Resources, Langfang 065000, China

Received:2004-12-20 Revised:2004-12-20 Online:2004-12-20 Published:2004-12-20

摘要/Abstract

摘要： 平山板桥沟地区的英云闪长质片麻岩常量元素具有高硅、高铝、高钠和低钾的特点，稀土元素显示强烈分异，具有较高的(La／Yb)。值(34)，同时具有明显的Nb，Ta，Ti和P负异常，与太古宙TTG的特征完全一致。阴极发光和背散射研究表明，英云闪长质片麻岩中锆石具有密集震荡环带和较高的Th／U值，表现典型岩浆锆石的特点，但其外侧都有一高亮度(CL)的狭窄变质增生边。SHRIMP测试结果表明TTG的形成年龄为2536．5±9．8Ma，变质年龄为1802±43Ma。推测2500Ga西部块体向东部陆块俯冲形成了TTG，并导致五台陆块与太行山陆块拼合，使华北克拉通化，1．8Ga则为陆内的另一次构造事件。

Abstract: Geochemistry of tonalitic gneisses in Banqiaogou area of Pingshan county shows high Si，A1，Na and low K．strong differentiation in its REE pattern，with higher(La／Yb)N，and distinct negative anolnalies of Nb，Ta，Ti and P，which are nearly the same as those of TTG in Archean．CL and BSE images of zircons in the tonalitic gneiss display dense regular zones and high Th／U，indicating the features of magmatic zircons，and narrow metamorphic rims with high brightness．SHRIMP dating shows that the age of the magmatic emplacement and metamorphism of these TTG gneisses are 2 536±9．8 Ma and 1 802±43Ma，respectively．The conclusion is that the West block was subducted under the East block．The subduction was responsible for the intrusion of TIG ,and finally leading to the amalgamation of Wutai block with Taihangshan block．Another independent tectonothermal event within the continent occurred at C．1.8Ga ago．

杨崇辉, 杜利林, 万渝生, 刘增校. 河北平山英云闪长质片麻岩锆石SHRIMP年代学[J]. J4.

YANG Chong-hui1, DU Li-lin1, WAN Yu-sheng1, LIU Zeng-xiao2. SHRIMP Zircon U-Pb Chronology of Tonalitic Gneiss in Banqiaogou Area, Pingshan County, Hebei Province[J]. J4.