Song Chay-都龙杂岩体的组成、构造特点及其构造环境

发布时间：2019-01-06 20:30

【摘要】：Song Chay-都龙地体是华南板块的西南部最大岩浆岩杂岩体它已被认为是代表了前寒武纪基底。Song Chay 都龙杂岩体大部分位于在越南北部，另外部分向北延入中国云南省境内，在红河断裂带与文山-河江断裂之间。从构造几何形态来看SongChay 都龙杂岩体具有十分明显的弯隆形态，东西宽度约45km,南北长约80km. SongChay 都龙杂岩体组成由混合岩，花岗片麻岩和片麻岩，是一套变质变形花岗杂岩。它遭受多阶段强烈变形与变质改造,其与众不同的出露位置和出露特点受到众多地质学家们的关注。本文从几个方面对Song Chay 都龙杂岩体进行观察，开展了深研究。SongChay-都龙两部分的宏观组成特点与构造变形的测量和观察从Song Chay到都龙可观察到主要有三种岩石：1-由钾长石、斜长石、条纹长石组成的高温片麻岩；2-中低温片麻岩（花岗片麻岩）；3-白云母石英片岩（没有出现长石）。在花岗岩变质岩石中主要的矿物组成为石英、钾长石、斜长石和黑云母，次要矿物是角闪石、辉石、石榴石等，具有典型定向结构。在岩石中，其中矿物具有单向定向性，石英和长石单向延长很强烈，云母集中合体定向排列，共同的特点是岩石被强烈变质变形。在野外露头上可容易看见残斑，，残斑具有“σ”或“δ”形状。变形残斑表现为残斑沿着剪切方向被定向拉长，可见十分明显运动方向：长石旋转残斑均指示上部指向东南的剪切变形。而且发育的东南-西北向的矿物拉伸线理。本文试图通过了解Song Chay 都龙杂岩，其他周边地质构造特点，以期准确理解它们对Song Chay 都龙杂岩体剥露作用和意义。在Song Chay,都龙两部分岩石保存了不同的显微构造现象，是由变形-变质的程度作用所致形成了不同的显微构造的现象。在Song Chay 都龙地区发育的典型显微构造现象可为：晶内裂隙、波状消光、机械双晶、静态恢复重结晶、动态恢复重结晶、碎（残）斑系、条带状构造、S-C组构、矿物鱼和出溶构造。在显微构造现象来表现出了高温-中高温塑性变形证据，后来叠加低温变形改造。无论在宏观尺度上还是显微尺度上都反映了Song Chay 都龙杂岩体是遭受了多期变形叠加作用的结果。 Song Chay 都龙地体采用EBSD分析中石英的组构分析获得结果：具有3种不同应变历史的岩石中石英组构图。可见十分明显早期是高温，中高温条件后期叠加低温变形作用。 Song Chay 都龙年代学的分析，构造活动年龄442-402Ma代表了志留纪杨子板块与华夏板块陆内碰撞造山运动，也是加里东构造热事件，主要是以S型花岗岩为主，具有上部大陆地壳相似的微量素分布形式。在中生代（印支运动）Song Chay 都龙地体遭受了强烈的构造变形。在燕山运动发生大规模的岩浆侵入活动形成老君山花岗岩。
[Abstract]:The Song Chay- Dulong terrane is the largest magmatic complex in the southwest of the South China plate. It has been considered to represent the Precambrian basement. Song Chay Tudulong complex, most of which is located in northern Vietnam, and the other part extends northward into Yunnan Province, China. Between the Honghe fault zone and the Wenshan-Hejiang fault. According to the structural geometry, the SongChay Yudulong complex has a very obvious bending shape, the width of which is about 45km from east to west, and the length from north to south is about 80km. The SongChay Gudulong complex is composed of migmatite, granitic gneiss and gneiss, which is a set of metamorphic granitic complex. It has been subjected to multiple stages of intense deformation and metamorphism, and its distinctive outburst location and characteristics have attracted many geologists' attention. In this paper, the Song Chay Dulong complex is observed from several aspects. From Song Chay to Dulong, there are mainly three kinds of rocks: (1) high-temperature gneiss composed of potassium feldspar, plagioclase and striped feldspar; Gneiss (granitic gneiss) and 3-Muscovite quartz schist (no feldspar). The main minerals in granite metamorphic rocks are quartz, potassium feldspar, plagioclase and biotite, and the secondary minerals are hornblende, pyroxene, garnet and so on. Among them, minerals have unidirectional orientation, quartz and feldspar have strong unidirectional prolongation, and mica are concentrated in orientation. The common feature is that the rocks are strongly metamorphosed. It is easy to see the speckles on the outcrop in the field, which has the shape of "蟽" or "未". The deformed speckles are shown to be elongated along the shear direction, and the movement direction is very obvious. The feldspar rotating speckles indicate the shearing deformation of the upper part pointing to the southeast. Moreover, the mineral stretching line of southeast-northwest direction is developed. In this paper, we try to understand the characteristics of Song Chay Tudulong complex and other surrounding geological structures in order to accurately understand their exfoliation and significance to the Song Chay Tudulong complex. Different microstructural phenomena have been preserved in the two parts of Song Chay, Dulong, which are caused by the degree of deformation-metamorphism. The typical microstructural phenomena developed in the Song Chay area can be as follows: intragranular fissure, wave extinction, mechanical double crystal, static recovery recrystallization, dynamic recovery recrystallization, broken (remnant) speckle system, banded structure, S-C fabric. Mineral fish and exsolution structure. The microstructural phenomena show the evidence of plastic deformation at high-middle-high temperature and then superimpose low-temperature deformation. Both macroscopic and microscopic scales reflect that the Song Chay Yudulong complex is the result of multi-stage deformation superposition. The texture analysis of quartz in EBSD analysis is used to obtain the results of the Song Chay Tudulong terrane. The results are as follows: the composition of quartz groups in rocks with three different strain histories. It can be seen that the early stage is high temperature, the late superposition of low temperature deformation under medium high temperature condition. The age of tectonic activity, 442-402Ma, represents the intracontinental collision orogeny between the Yangzi plate and the Cathaysian plate in Silurian, and is also a Caledonian tectonic thermal event, mainly of S-type granite. The distribution of trace elements is similar to that of the upper continental crust. The Mesozoic (Indosinian) Song Chay Tudulong terrane suffered a strong tectonic deformation. Large-scale magmatic intrusions occurred during the Yanshanian movement to form Laojunshan granite.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P583

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