Discovery of Late Paleozoic retrograded eclogites from the middle part of the northern margin of Nor

来源 :科学通报 | 被引量 : 0次 | 上传用户:qq20881010
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The retrograded eciogites have been discovered in the middle part of the northern margin of the North China Craton, which occur as lens or boudin within biotite-plagioclase gneisses in Paleoproterozoic Hongqiyingzi Group. The peak eclogite facies (P > 1.40-1.50 GPa, T = 680-730℃) mineral assemblage is composed of garnet, omphacite and rutile (+ quartz), which was overprinted by the granulite facies mineral assemblage of vermicular symplectite of sodic clinopyroxene and plagioclase which replaced the precursory omphacite, and then amphibolite facies retrograded minerals with characterization of Amp+Pl kelyphitic rim and symplectite, and amphibole replaced clinopyroxene. The protolith of retrograded eclogites is oceanic basalt formed at 438 + 11 Ma. The peak eclogite facies metamorphic age of the retrograded eclogite is 325 + 4 Ma. These relict eclogites may be formed by the subduction of Paleo-Asian oceanic crust beneath the North China Craton during Late Paleozoic. The discovery of relict eclogite in this paper provides a new insight into farther understanding of tectonic evolution of the northern margin of the North China Craton, and the relationship between the Paleo-Asian Ocean and the North China Craton.
其他文献
Since 1985, samples with a total weight of more than 14,000 kg, mainly from three key sections in western and northwestern Hunan, South China, have been process
本文首先对预应力技术在超长混凝土结构的应用进行概述,然后从设计方面和施工方面对预应力在超长混凝土结构中的应用分别进行了分析,旨在与同行交流,不断提高预应力在超长混凝土
人工挖孔桩特有的大承载力优势得到了许多设计、施工单位的认可,确实是一种在软弱地基上经济实用的基础形式,但在施工中还存在着一些问题。本文结合作者工作实践及工程实例,分析
Ultramafic xenoliths are common in Tietonggou intrusion, Laiwu, Shandong Province. Peridotite xenoliths develop two-stage metasomatism popularly: (i) The early
In order to understand the relationship be tween the community structure of bacteria in ice core and the past climate and environment, we initiated the study on
本文针对河西地区农村公路水泥混凝土路面的特点,分析了农村公路水泥混凝土路面常见病害的产生原因,并提出了相应的预防和处治措施。
短线匹配预制箱梁节段、上行式架桥机安装工艺目前在国内却较少采用,属较为新型的一种施工工艺,该工艺要求箱梁拼缝采用高强环氧胶粘结。对箱梁匹配面施胶在现行的路桥施工规范
水利工程的特殊性,一般都要经历冬天施工,而水利工程冬天混凝土施工一直都是水利工程中的难题。本文分析了水利工程混凝土冬季施工存在的问题,并提出了水利工程混凝土冬季施工的
In order to further constrain the tectonic configuration of the Tianshan fold belt and the blocks of its northern and southern sides prior to the Eocene India/E
本文结合阳阳高速公路阳江至阳春段工程,该工程部分水泥混凝土路面采用机制砂代替天然河砂来拌制水泥混凝土进行路面施工,对其进行大量试验以研究机制砂代替天然河砂对水泥混凝