北秦岭西段红花铺俯冲型侵入体LA-ICPMS定年及其地质意义

现代地质 ›› 2006, Vol. 20 ›› Issue (4): 536-544.

北秦岭西段红花铺俯冲型侵入体LA-ICPMS定年及其地质意义

王洪亮^1,2，何世平^2,3，陈隽璐^2,3，徐学义²，孙勇^1,4，第五春荣⁴

1西北大学地质学系，陕西西安710069；2西安地质矿产研究所，陕西西安710054；
3中国地质大学地球科学学院，湖北武汉430074； 4西北大学大陆动力学重点实验室，陕西西安710069

收稿日期:2006-04-23 修回日期:2006-09-05 出版日期:2006-04-20 发布日期:2006-04-20
作者简介:王洪亮，男，高级工程师，博士研究生，1968年出生，岩石大地构造专业，主要从事区域地质调查研究工作。
基金资助:
中国地质调查局国土资源大调查研究项目(1212010510416)

LA-ICPMS Dating of Zircon U-Pb and Tectonic Significance of Honghuapu Subduction-Related Intrusions in the West Segment of Northern Qinling Mountains

WANG Hong-liang^1,2，HE Shi-ping^2,3， CHEN Juan-lu^2,3， XU Xue-yi²，SUN Yong^1,4， DIWU Chun-rong⁴

1Department of Geology， Northwest University，Xi'an，Shaanxi710069, China ；
2 Xi'an Institute of Geology and Mineral Resource，Xi'an，Shaanxi710054, China；
3Faculty of Earth Science，China University of Geosciences，Wuhan,Hubei430074, China；
4The Key Laboratory of Continental Dynamics， Northwest University，Xi'an，Shaanxi710069, China

Received:2006-04-23 Revised:2006-09-05 Online:2006-04-20 Published:2006-04-20

摘要/Abstract

摘要：

北秦岭造山带西段红花铺侵入体的岩石类型为中细粒英云闪长岩，具俯冲型花岗岩类的地球化学特征。通过对其中所获锆石的形态及CL图像特征的研究，分辨出3种不同成因的锆石，通过高精度的LA-ICPMS(激光剥蚀等离子体质谱)单颗粒锆石微区U-Pb同位素年龄测定，获得(1 765.1±8.4）Ma、(450.5±1.8）Ma、(413.5±1.3）Ma的3组年龄值，分别为继承锆石年龄、成岩锆石年龄和变质锆石年龄，代表了3期构造热事件的时限，可能是吕梁运动和加里东运动在北秦岭西段的地质记录。红花铺侵入体英云闪长岩(450.5±1.8）Ma的成岩年龄可能代表了北秦岭西段早古生代俯冲带岛弧的形成时代。红花铺俯冲型侵入体的形成时代及构造环境的确定，对研究北秦岭造山带元古宙—早古生代大地构造格局、构造演化及中国大陆动力学机制具有重要意义。

关键词: 北秦岭, 红花铺侵入体, LA-ICPMS定年, 构造意义

Abstract:

Honghuapu intrusions in the west segment of Northern Qinling Mountains are dominated by tonalite with medium-fine-granular structure, which carry the geochemic characteristics of subduction-related granitic rocks. Zircons obtained from Honghuapu intrusions can be divided into three groups according to the shapes and CL images. Based on the results of LA-ICPMS dating of zircon U-Pb isotope, we get three ages of (1,765-1±8-4）Ma, (450.5±1.8）Ma and (413.5±1.3）Ma, these ages indicate different formation age of hereditary zircons, magmatic crystallization zircons and metamorphic zircons, which may represent three tectonic-thermal events coincide to Lüliang Movement and Caledonia Movement respectively. Whereas, the age of (450.5±1.8）Ma is the formation age of Honghuapu intrusions and also implies the formation age of Early Paleozoic island arcs in Northern Qinling. These new LA-ICPMS datings of zircon U-Pb have great significance to the study of Proterozoic and Early Paleozoic tectonic framework, evolution and dynamic mechanism of Qinling Mountains.

Key words: Northern Qinling Mountains, Honghuapu intrusions, LA-ICPMS dating, tectonic significance

中图分类号:

P588.1
P597

王洪亮，何世平，陈隽璐，徐学义，孙勇，第五春荣. 北秦岭西段红花铺俯冲型侵入体LA-ICPMS定年及其地质意义[J]. 现代地质, 2006, 20(4): 536-544.

WANG Hong-liang，HE Shi-ping， CHEN Juan-lu，XU Xue-yi，SUN Yong，DIWU Chun-rong. LA-ICPMS Dating of Zircon U-Pb and Tectonic Significance of Honghuapu Subduction-Related Intrusions in the West Segment of Northern Qinling Mountains[J]. Geoscience, 2006, 20(4): 536-544.

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