| 胶东莱西地区高压麻粒岩的Sm-Nd同位素年代学 |
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| 引用本文： | 李永刚,翟明国,刘文军,郭敬辉.胶东莱西地区高压麻粒岩的Sm-Nd同位素年代学[J].地质科学,1997,32(3):283-290. |
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| 作者姓名： | 李永刚 翟明国 刘文军 郭敬辉 |
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| 作者单位： | 中国科学院地质研究所, 北京100029 |
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| 摘 要： | 在胶东地区莱西-莱阳-栖霞一带的晚太古代花岗片麻岩中,出露一条长约200多公里,NE向展布的高压基性麻粒岩-超镁铁质岩带。由于这条岩带东邻苏鲁高压-超高压变质带,西接华北克拉通基底的古老变质岩,因此其区域构造归属以及大地构造意义是一个十分重要的问题。本文分析的高压基性麻粒岩样品具有降压退变质结构,退变质矿物组合为麻粒岩相。矿物-全岩Sm-Nd等时线年龄为1752Ma,全岩T(DM)模式年龄为2788Ma,与华北克拉通北缘的高压基性麻粒岩的同位素年龄完全相似。根据高压麻粒岩-超镁铁质岩的围岩片麻岩特征和同位素年龄,可以确定这条出露于华北陆块东缘的岩带是早前寒武纪华北克拉通下地壳岩石,其抬升与华北陆块与扬子陆块的拼合有关。
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| 关 键 词： | 同位素年代学 Sm-Nd同位素年龄 高压基性麻粒岩 胶东 |
| 收稿时间： | 1997-02-24 |
| 修稿时间： | 1997-02-24; |
Sm-Nd GEOCHRONOLOGY OF THE HIGH-PRESSURE BASIC GRANULITE, IN LAIXI, EASTERN SHANDONG |
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| Li Yonggang,Zhai Mingguo,Liu Wenjun,Guo Jinghui.Sm-Nd GEOCHRONOLOGY OF THE HIGH-PRESSURE BASIC GRANULITE, IN LAIXI, EASTERN SHANDONG[J].Chinese Journal of Geology,1997,32(3):283-290. |
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| Authors: | Li Yonggang Zhai Mingguo Liu Wenjun Guo Jinghui |
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| Institution: | Institute of Geology, Academia Sinica, Beijing 100029 |
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| Abstract: | A high-pressure basic granulate-ultramafic rock belt, which is about 200km long and trends NE, occurs in the late Archaean orthogneisses in Laixi-Laiyang-Qixia area, eastern Shandong. This belt is located east to the Su-lu I1HPM terrain and west to the Archaean rocks of the North China craton, therefore its geological situation and implication for collision between the North China plate and Yangtze plate is very important. The analyzed sample of high-pressure basic granulate has decreasing pressure metamorphic texture. The second mineral assemblage is of granulate fades. The sample yields an internal mineral-whole rock Sm-Nd isochron of 1752Ma. The T(DM)age of whole rock is 2788Ma. These data are very similar to those of high-pressure basic granulates in northern North China craton. Considering the pertrological and geochemical characteristics and isotopic ages, the high-pressure granulate-ultramafic rock belt in eastern Shandong is suggested to belong the Norih China craton and to be rocks of the early Precambrian lower crust. Their rifting form the deep crustal level is related to collision between the North China plate and Yangtzi plate. |
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| Keywords: | Isotopic geochronology Sm-Nd isotopic age High-pressure basic granulite Eastern Shandong |
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