庞绪成, 韩迪, 纵瑞,等.华北南缘小秦岭小河岩体锆石U-Pb定年及地质意义[J].河南理工大学学报（自然科学版）,2021,40(6):54-63.

PANG X C, HAN D, ZONG R,et al.Zircon U-Pb dating and geological significance of Xiaoqinling Xiaohe pluton in the southern margin of North China[J].Journal of Henan Polytechnic University(Natural Science) ,2021,40(6):54-63.

华北南缘小秦岭小河岩体锆石U-Pb定年及地质意义

庞绪成1, 韩迪1, 纵瑞2, 段启超1, 张岩2, 张鑫1

1.河南理工大学 资源环境学院，河南 焦作454000;2.河南省地质矿产勘查开发局 第二地质矿产调查院，河南 郑州 450003

摘要:小河岩体是华北南缘小秦岭地区的四个规模较大的花岗岩体之一，已有岩体年龄数据尚存在不足。为精确测定小河岩体年龄，在野外确定岩体侵入期次的基础上，对花岗岩进行取样，经锆石挑纯后，用LA-ICP-MS方法对样品进行U-Pb测年，样品测点大部分位于或接近207 Pb/235 U-206Pb/238 U 一致线。测年数据表明，小河花岗岩的成岩年龄为（1 795 ±70） Ma，中条运动晚期。在熊耳中晚期，受到了较大规模的变质作用及岩脉入侵。之后，虽有多期次构造岩浆作用，形成穿插到岩体中的多期岩脉，但规模和强度有限，显示区域岩浆活动方式从孕育侵入→强力喷发→能量减弱的侵入历程。岩体形成与区域金银成矿时差巨大，推测对区域成矿的贡献有限。 

关键词:小河岩体;锆石U-Pb定年;地质意义;小秦岭;华北南缘

doi:10.16186/j.cnki.1673-9787.2020040060

基金项目:国家重点研发计划项目（2016YFC0600106-4）；河南省“探矿权、采矿权”价款项目（2018-22-06）；河南省地质矿产勘查开 发局地质科研项目（2017-01）

收稿日期:2020/04/15

修回日期:2020/05/20

出版日期:2021/11/15

Zircon U-Pb dating and geological significance of Xiaoqinling Xiaohe pluton in the southern margin of North China

PANG Xucheng1, HAN Di1, ZONG Rui2, DUAN Qichao1, ZHANG Yan2, ZHANG Xin1

1.Institute of Resources and Environment， Henan Polytechnic University， Jiaozuo  454000 ， Henan， China;2.No.， Bureau of Geology and Miniral Exploration and Development of Henan Province， Zhengzhou  450000 ， Henan， China

Abstract:Xiaohe pluton is one of the four large-scale granites in the Xiaoqinling area ， southern margin of North China. The existing rock age data are still insufficient. In order to accurately determine the age of Xiaohe pluton ， based on the determination of intrusive periods in the field ， the granite was sampled and purified by zircon ， and then U-Pb dating was carried out by LA-ICP-MS. Most of the samples were located at or near the3Pb，/2U-"Pl/""U consistent line. The dating data showed that the crystallization age of Xiaohe granite was（1 795 ±70） Ma， which was in the late Zhongtiao orogeny. In the middle and late period of Xiong' er ， it was subjected to a large scale of metamorphism and dike invasion. Afterwards ， although the multi-stage tectonomagmatism formed the multi-stage dikes interpenetrating into the rock mass ， the scale and strength were limited. It showed the development process of regional magmatic activity from inoculation intrusion-strong eruption-energy weakening to intrusion. There was a huge time difference between the pluton formation and the regional gold and silver mineralization， so it was speculated that the contribution to regional metallogenic process was limited.

Key words:Xiaohe pluton;zircon U-Pb dating;geological significance;Xiaoqinling;southern margin of North China

 华北南缘小秦岭小河岩体锆石U-Pb定年及地质意义_庞绪成.pdf