本文關(guān)鍵詞： 狼山 韌性剪切帶 宏微觀構(gòu)造 地球化學(xué)　出處：《昆明理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：位于華北克拉通北緣西段的內(nèi)蒙古狼山構(gòu)造帶,是研究華北板塊與西伯利亞板塊相互作用的重點(diǎn)地區(qū),也是中國境內(nèi)研究超大型礦床成礦作用的重要地區(qū)之一。狼山構(gòu)造帶內(nèi)有著不同的構(gòu)造形式,而韌性剪切帶,是狼山構(gòu)造帶內(nèi)主要的構(gòu)造型式之一,是地殼深層次構(gòu)造的反映。根據(jù)韌性剪切帶內(nèi)糜棱巖帶的規(guī)律性分布,狼山構(gòu)造帶內(nèi)可劃分出三條規(guī)模較大的韌性剪切帶和數(shù)條次級(jí)韌性剪切帶。本論文在前人研究的基礎(chǔ)上通過宏觀構(gòu)造與微觀構(gòu)造相互結(jié)合的方法,對(duì)狼山構(gòu)造帶內(nèi)的三條主要韌性剪切帶的幾何學(xué)、運(yùn)動(dòng)學(xué)、動(dòng)力學(xué)、地球化學(xué)、變形年代等方面進(jìn)行了系統(tǒng)研究,取得了以下新的認(rèn)識(shí)：1.通過韌性剪切帶的幾何學(xué)研究查明,狼山韌性剪切帶內(nèi)發(fā)育有不同類型的糜棱巖或構(gòu)造片巖,糜棱巖面理產(chǎn)狀平行于狼山山體走向,且糜棱巖面理中僅發(fā)育一組礦物拉伸線理,線理向NE或SW方向傾伏。2.通過對(duì)狼山韌性剪切帶的宏觀構(gòu)造特征研究,發(fā)現(xiàn)狼山韌性剪切帶內(nèi)的糜棱巖中存在構(gòu)造透鏡體、旋轉(zhuǎn)碎斑、Ω型鞘褶皺、石香腸等構(gòu)造,且這些宏觀構(gòu)造均指示韌性剪切帶的剪切指向以左行剪切為主。3.通過詳細(xì)定向薄片的鏡下觀察,系統(tǒng)的對(duì)狼山韌性剪切帶的顯微構(gòu)造特征進(jìn)行了研究,發(fā)現(xiàn)狼山韌性剪切帶的顯微構(gòu)造主要有核幔構(gòu)造、石英的動(dòng)態(tài)重結(jié)晶、波狀消光、石英亞晶�；驒C(jī)械雙晶、云母扭折帶等構(gòu)造。通過具有指示剪切方向的顯微構(gòu)造,如旋轉(zhuǎn)碎斑系、不對(duì)稱壓力影、S-C組構(gòu)、云母魚等,指示了狼山韌性剪切帶剪切方向以左行剪切為主,與野外確定的剪切方向一致。4.通過對(duì)狼山韌性剪切帶的巖石組構(gòu)分析,說明了狼山Ⅰ、Ⅱ號(hào)韌性剪切帶在韌性剪切變形過程中,石英具有柱面滑移和底面滑移2種滑移機(jī)制,其中Ⅰ號(hào)韌性剪切帶以高溫柱面c滑移和中-高溫柱面a滑移為主,Ⅱ號(hào)韌性剪切帶具有中-高溫柱面a和低溫底面a滑移的特點(diǎn),且該兩條韌性剪切帶石英組構(gòu)特征所顯示的剪切指向與野外及鏡下確定的剪切方向基本一致,均為左行剪切。5.利用狼山韌性剪切帶定向薄片的顯微構(gòu)造特征與應(yīng)變間的關(guān)系,運(yùn)用石英顆粒重結(jié)晶法和蠕變方程計(jì)算得到狼山韌性剪切帶古差應(yīng)力值為56-115mp,平均應(yīng)變速率在10-13—10-14m/s。6.在地球化學(xué)方面,對(duì)狼山Ⅱ號(hào)韌性剪切帶中具有明顯塑性流變特征的硅質(zhì)條帶狀灰?guī)r進(jìn)行了常量元素、微量元素和稀土元素的分析,分析結(jié)果表明不同變形強(qiáng)度的硅質(zhì)條帶狀灰?guī)r與原巖的成分存在著差異變化。條帶狀灰?guī)r中的大多數(shù)常量元素和微量元素均為富集元素,隨著變形程度的增加而帶入,且各構(gòu)造巖與原巖的稀土元素配分模式基本一致,也表明了稀土元素在剪切過程中具有一定的相對(duì)穩(wěn)定性和同源性。7.對(duì)狼山韌性剪切帶中Ⅱ、Ⅲ號(hào)剪切帶進(jìn)行了40Ar/39Ar測(cè)年,測(cè)試結(jié)果表明狼山Ⅱ、Ⅲ號(hào)韌性剪切帶均形成于晚泥盆世末,說明了狼山構(gòu)造帶在晚泥盆世末到早石炭世發(fā)生了一次顯著地構(gòu)造活動(dòng)。
[Abstract]:Located in the northern margin of the North China Craton of Inner Mongolia Langshan tectonic belt, is the study of the North China plate and the Siberia plate interaction in key areas, and it is also one of the important areas of research within the territory of Chinese deposits. Large super function of Langshan tectonic belt with different structure form, and the ductile shear zone, is one of the main tectonic types with Langshan structure that is a reflection of the deep crustal structure. According to the ductile shear zone in the mylonite zone distribution, Langshan tectonic belt can be divided into three large scale ductile shear zone and several secondary ductile shear zone. This paper on the basis of previous studies by means of macro structure and micro structure with each other, the Langshan tectonic belt in three major ductile shear zone geometry, kinematics, dynamics, geochemistry, makes a systematic research on the deformation in the aspects made by Under the new understanding: 1. through the study of geometry of the ductile shear zone identified Langshan ductile shear zones developed different types of mylonite or tectonic schist, mylonite foliations parallel to the strike Langshan Mountain, and the rnylonite foliation only developed a set of mineral stretching lineation, lineation to NE or SW direction of plunging.2. through the research on the macroscopic structural characteristics of Langshan ductile shear zone, mylonite are found in tectonic lens Langshan in the ductile shear zone, rotating porphyroclasts, Omega sheath fold, stone sausage structure, and the macro structure indicates shear ductile shear zone observation point to the left lateral shearing.3. with directional sheet under the microscope, on the microstructural characteristics of the ductile shear zone of Langshan Mountain was studied, found that the core mantle structure mainly Langshan microstructure of ductile shear zone, dynamic recrystallization of quartz, wavy extinction, quartz Sub grain or mechanical twinning, mica kink band structure. By having a microstructure indicating the shear direction, such as rotational porphyroclast, asymmetric pressure shadow, S-C fabric, mica fish, indicating the Langshan ductile shear to left lateral shear dominated with shear direction, shear direction and field determined by.4. agreement the rock group of Langshan ductile shear zone structure analysis shows that Langshan I, II ductile shear zone in the ductile shear deformation process, quartz has prismatic slip and the bottom surface of the 2 slip slip mechanism, the effect of ductile shear zone in high temperature and in - cylinder slip cylindrical C a slip characteristics, II the ductile shear zone with high temperature and low temperature a a cylindrical bottom slip, and the two ductile shear zone quartz fabric characteristics show the shear direction and determine the direction of shear field or under microscope are basically the same, are left shear by.5. The relationship between microstructure characteristics and strain of Langshan ductile shear zone between oriented thin sections, using quartz grain recrystallization method and the creep equation to calculate ancient Langshan ductile shear zone differential stress value is 56-115mp, the average strain rate of 10-13 - 10-14m/s.6. in geochemistry, obvious plastic rheological characteristics of No. 2 ductile shear mountain wolf with with siliceous banded limestone for analysis of major elements, trace elements and rare earth elements, the results showed that different deformation intensity of siliceous banded limestones and protolith composition differences change. Most major elements of banded limestone and trace elements are enriched with the elements, and to the increase of deformation degree, and rare earth elements in various tectonic rocks and rock distribution patterns are basically the same, also shows that the rare earth elements have a certain relative stability in the shearing process and homology .7. of Langshan ductile shear zone II, III shear bands were 40Ar/39Ar dating. The test results show that Langshan II, III ductile shear zone was formed in the late Devonian late that Langshan tectonic belt in Late Devonian to late Early Carboniferous had a significant tectonic activity.

【學(xué)位授予單位】：昆明理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P542

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