论孔兹岩——地球上特殊地质过程的记录  

Khondalite revisited——record of special geological processes on Earth

作　　者：翟明国 ZHAI Mingguo(School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China;School of Earth Sciences,Zhejiang University,Hangzhou,Zhejiang 310027,China;Department of Geology,Northwest University,Xi'an,Shaanci 710069,China;State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academyof Sciences,Beijing100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]南京大学地球与工程学院,江苏南京210023 [2]浙江大学地球科学学院,浙江杭州310027 [3]西北大学地质系,陕西西安710069 [4]中国科学院地质与地球物理研究所岩石圈国家重点实验室,北京100029 [5]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地质学报》2022年第9期2967-2997,共31页Acta Geologica Sinica

基　　金：国家自然科学基金重大项目“大陆地壳演化与早期板块构造”(编号41890834);中国科学院前沿重点项目(编号QYZDYSSW-DQC017)和先导项目(编号XDB18030205)联合资助的成果。

摘　　要：近些年来,孔兹岩成为前寒武纪地质、变质地质以及大陆演化研究中一个使用非常普遍的词。在不少的文章中,孔兹岩被赋予特定的地质含义。例如,在变质作用中联系到高温-高压麻粒岩相或者是高温—超高温变质作用;在地质历史中,代表元古宙的特定时期;在构造环境中联想到古老大陆边界或者克拉通盖层,等等。这些说明孔兹岩类岩石的研究具有重要的意义。经过仔细分析,还可看到不同的研究者对于孔兹岩的定义、岩石组合和出露规律、变质环境和变质历史、构造指示意义诸方面的理解都存在很大的差异,甚至有时各说各话,不利于交流或产生歧义和误解。因此,有必要对孔兹岩一词的定义以及它的使用做一个梳理和界定,对其内涵、构造意义以及相关问题进行讨论。这就是本文的初衷。此外,本文还认为,华北的古元古代孔兹岩类的原岩是与其他沉积岩共生的富铝沉积岩,由于它们经历了高级变质作用,因此有相当比例的沉积岩变成原地-准原地重熔的花岗岩,并与变质的基性岩墙或岩体密切共生。含孔兹岩的沉积岩系具有沉积环境稳定的特点,不含或罕见火山岩层,是在新太古代克拉通化和古元古代“静寂期”之后的代表性裂谷型沉积组合。“静寂期”超过200 Ma,使得古老的陆壳有长期和充裕的风化时间,沉积物具有充分的搬运和分选特点,伴有厚层碳酸盐沉积,并以含有较普遍或较频繁出现的碳质黑色页岩夹层而与太古宙的沉积岩石相区别。华北的孔兹岩类的分布以及特点,具有全球可比性,对于理解可能的休伦裂谷事件和相伴随的大氧化事件具有举足轻重的意义;同时对于理解古元古代末期成山纪(Orosirian)的构造事件以及构造体制的重要转变也有不可替代的作用。孔兹岩是地球特殊地质过程的记录。In recent years, khondalite has become a very popular term in the study of Precambrian geology and metamorphic geology as well as continental evolution. Khondalite has different geological and tectonic implications in some articles. For example, khondalite is suggested to have undergone either high-temperature and moderate-pressure(amphibolite-granulite facies) metamorphism or high-temperature and ultra-high-temperature metamorphism. And as a result, it is a representative of the Earth’s Paleoproterozoic environment, or its occurrence marks the ancient continental boundaries or cover layers of stable cratons, and so on. Undoutedly, the study of khondalite is of great significance. However, the concept of khondalite is used in different ways, refecting that researchers have different understanding of the definition of khondalite, its rock assemblage and distribution, sedimentary environment and metamorphic history, tectonic implications and other aspects. This present situation has impeded the useful interchange of ideas and even led to ambiguity and misunderstanding. Therefore, it necessiates an effort to clearly define the term khondalite and to discuss its connotation, tectonic implication and other relavant issues. This is just my original intention to write this paper. This paper first reviewes the study of khondalite and related rocks showing that khondalite-bearing meta-sedimentary rocks. The khondalitic rocks in the North China Craton(NCC) consists basically of three parts, the lower coarse-grained clastic rocks, middle peltites and argillaceous rocks, and upper carbonate rocks. All the sedimentary successions underwent high-grade metamorphism, with some of which had changed into anatectic magma, as manefested by occurrences of large quantities of autochthonous or para-autochthonous granites. Meta-gabbroid dykes and bodies are also associated with the khondalite. Presence of quartz arenite and absence of volcanic rock in kondalitic rocks indicate sedimentation happened in a relatively stable tectonic set

关 键 词：孔兹岩 定义 内涵 构造意义 特殊记录 

分 类 号：P588.3[天文地球—岩石学]