区域变质作用与中国大陆地壳的形成与演化

发布时间：2017-12-26 21:29

本文关键词：区域变质作用与中国大陆地壳的形成与演化　出处：《岩石学报》2016年09期 　论文类型：期刊论文

【摘要】：在编制1∶500万中国变质地质图的基础上,本文总结了中国主要变质带的演化以及各变质带与中国大陆地壳形成演化之间的内在联系。虽然在华北和华南克拉通都有古太古代到中太古代的变质年代记录,但是由于后期改造其变质作用的特点及与区域构造背景的联系已难以追索。新太古代末-古元古代初期的变质作用在华北克拉通表现最明显,这期变质作用紧随大规模的TTG岩浆作用,普遍具有逆时针的P-T演化轨迹,反映了地幔柱主导的岩浆-变质事件特点。古元古代晚期的变质事件在华北、华南、塔里木克拉通都有强烈反映。这期变质作用以形成具有顺时针P-T演化轨迹的高压麻粒岩为特点,与形成Columbia超大陆的一些造山带的特点类似,但是这三个不同克拉通在与Columbia聚合的时间和空间方位上存在差异。华南克拉通是相对年轻的克拉通,是沿新元古代江南造山带扬子和华夏地块拼合的产物。新元古代江南造山带的火山岩形成时代和变质作用程度从北东向南西迁移,反映了造山过程逐渐迁移和剪刀式闭合的特点。形成华南克拉通后,在其东南缘又先后经历了加里东期和印支期的变质改造,并且由北西向南东变质带从加里东期转变为印支期,但是这两期变质作用的构造背景尚不很清楚。中国南北大陆的聚合首先从西昆仑-阿尔金-北祁连-北秦岭-桐柏开始,所反映的变质作用是早古生代的蓝片岩相和榴辉岩相变质岩相伴产出,表明经历了从洋壳俯冲到陆陆碰撞的演化过程。中国东部的南北大陆到印支期才最终汇聚,相应的变质作用以南部出现高压蓝片岩相、北部出现超高压的榴辉岩相变质带为特点,表明南方大陆向北方大陆的俯冲。超高压带内普遍含有柯石英,意味着大规模的陆壳深俯冲。华北克拉通和塔里木克拉通以北的中亚造山带内存在多条从早古生代到晚古生代的变质带和多条蓝片岩相变质带,表明这是一个由多阶段、多条变质带组成的造山区。但是其变质作用的空间和时间演化还有待进一步深入。青藏高原变质带具有北老南新的空间分布特点,最北部的印支期龙木错-双湖-澜沧江变质带反映了原特提斯和古特提斯洋的碰撞拼合过程,北部的燕山期班公湖-怒江变质带和中部的喜马拉雅早期雅鲁藏布江变质带反映了新特提斯洋的两次碰撞拼合过程,南部喜马拉雅晚期的高喜马拉雅变质带反映了印度板块向北俯冲导致的高原快速隆升过程。
[Abstract]:Based on the compilation of 1: 5 million China metamorphic geological map, this paper summarizes the evolution of the main metamorphic belts in China, and the internal relations between the metamorphic belts and the crustal formation and evolution of the Chinese mainland. Although in the North China and Southern China both have carat Archean metamorphic age to mesoarchean records, but due to the characteristics of the late reformation of metamorphism and regional tectonic background relation has been difficult to recover. At the end of the late Archean metamorphic Paleoproterozoic early in the North China Craton is the most obvious, the metamorphism followed by TTG magmatism in large scale, generally has a counter clockwise P-T paths, reflects the characteristics of the mantle plume dominated by magmatic metamorphic events. Late Paleoproterozoic metamorphic events are strongly reflected in the north, Southern China, through the Tarim craton. This metamorphism is characterized by the formation of high-pressure granulites with clockwise P-T evolution. It is similar to the characteristics of some orogenic belts that form the Columbia supercontinent. However, these three cratones differ in the temporal and spatial directions of Columbia polymerization. The Southern China craton is a relatively young craton, which is the product of the combination of the Yangtze and the Huaxia massif in the Neoproterozoic Jiangnan orogenic belt. The Neoproterozoic Jiangnan orogenic belt migrated from NE to NW in the age of formation and metamorphism, reflecting the gradual migration of orogenic process and the scissors closure. After the formation of Southern China craton, it experienced Caledonian and Indosinian metamorphism in the southeastern margin, and changed from Caledonian to Indosinian, but the tectonic setting of these two metamorphism is not yet clear. First of all, North and South Chinese polymerization from West Kunlun Altyn Tagh North Qilian - North Qinling Mountains - Tongbai, metamorphism is reflected in the early Paleozoic blueschist facies and eclogite facies metamorphic rocks accompanied by output, shows that the evolution from subduction to continental collision. The southern and northern continent of China was finally converged to Indo Chinese epoch. The corresponding metamorphism is characterized by high-pressure blueshite facies in the South and UHP eclogite facies metamorphic belt in the north, indicating the subduction of the southern continent to the northern continent. Ultra high pressure zone generally contain coesite, means that large-scale continental subduction. There are multiple metamorphic belts from the early Paleozoic to late Palaeozoic and many blue stripe facies metamorphic belts in the Central Asian orogenic belt north of the North China Craton and the Tarim craton, indicating that this is an orogenic zone composed of multi stages and multiple metamorphic belts. However, the evolution of the space and time of its metamorphism remains to be further studied. The spatial distribution characteristic of North South Tibetan Plateau old metamorphic belt, the northern Indosinian Longmucuo Shuanghu - Lancang River metamorphic belt reflects the collision between Dhi Te Tis and the Paleo Tethys ocean, northern Yanshan during the Bangong Lake Nu River metamorphic belt and central Himalaya early Brahmaputra metamorphic belt reflects two collisions the matching process of the Neo Tethys ocean, the southern Himalaya Himalaya high metamorphic zone reflects the late northward subduction of India plate led to the rapid uplift of the plateau process.
【作者单位】：中国地质科学院地质研究所;
【分类号】：P588.34
【正文快照】： 区域变质作用常发生在特定的构造部位,通过变质作用演化特点的研究可以追索变质岩系在变质作用发生的过程中所处的构造环境。板块构造学说提出以后,变质作用的形成和演化与板块离散、俯冲、碰撞等机制联系日益紧密(Smish,1984;Bucher and Frey,1994;Barker,1998;Brown,2001;张

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