【摘要】：理塘地區(qū)斷裂構(gòu)造位于三江特提斯造山帶東緣,松潘-甘孜造山帶西南緣,揚子板塊西側(cè),是中國大陸地殼中三江特提斯造山帶與松潘—甘孜造山帶的重要組成部分。理塘地區(qū)位于青藏高原東緣,此處斷裂構(gòu)造的幾何學(xué)、運動學(xué)、動力學(xué)研究對于三江特提斯造山帶、松潘-甘孜造山帶乃至揚子板塊的形成及演化具有重要意義。理塘地區(qū)斷裂構(gòu)造從平面幾何展布上看可以劃分為主要由3個方向的斷裂組成,分別是南北向(S-N)斷裂、北西-南東(NW-SE)向斷裂和北東-南西(NE-SW)向斷裂。本文應(yīng)用構(gòu)造解析方法對理塘地區(qū)露頭尺度的斷裂構(gòu)造幾何形態(tài)進(jìn)行了觀測、對斷裂構(gòu)造的運動學(xué)與動力學(xué)方面解析并對本區(qū)內(nèi)斷裂構(gòu)造變形期次和區(qū)域構(gòu)造演化進(jìn)行了初步探討。本文認(rèn)為自印支期以來,理塘地區(qū)斷裂構(gòu)造變形次數(shù)至少可達(dá)6次。早在印支晚幕初期發(fā)生了NW-SE方向的碰撞擠壓,在此期應(yīng)力作用下,形成了NW向的劈理,本文將此次碰撞擠壓作用作為研究區(qū)內(nèi)的第一期構(gòu)造變形。第二期最大主應(yīng)力方向為NE-SW,發(fā)生在印支晚幕晚期。在此期應(yīng)力作用下,形成了斷層面傾向為NE、SW的斷層。這些斷層帶內(nèi)后期填充了大量石英脈。第三期應(yīng)力性質(zhì)為拉張,最小主應(yīng)力方向為NNE-SSW,在燕山中晚期此應(yīng)力作用下,以前形成的走向為NW的斷層被拉伸、擴大(此時石英脈形成)。第四期應(yīng)力方向為E-W,在喜馬拉雅運動中期此期應(yīng)力作用下,對以前期次形成的斷層、節(jié)理以及斷層內(nèi)的石英脈不同程度錯動,并形成本期次NE走向的斷層。第五期應(yīng)力方向為NE-SW,在上更新世早期此期應(yīng)力作用下,再次對以前期次形成的斷層、節(jié)理以及斷層內(nèi)的脈體不同程度錯度,并且強化NW走向的斷層。第六期應(yīng)力方向性質(zhì)不明,形成時間最晚,約為早更新世。特征斷層多窄小(2-3cm),帶內(nèi)充填大量斷層泥和碎粒,且無石英脈充填。正是多方向多期次的區(qū)域應(yīng)力造就了如今地質(zhì)構(gòu)造復(fù)雜的理塘地區(qū)斷裂構(gòu)造。
[Abstract]:The fault structure in Litang area is located in the eastern margin of the Sanjiang Tethys orogenic belt, the southwest margin of the Songpan-Ganzi orogenic belt and the west side of the Yangtze plate. It is an important part of the middle Sanjiang Tethys orogenic belt and the Songpan-Ganzi orogenic belt in the Chinese mainland. The Litang area is located in the eastern margin of the Qinghai-Tibet Plateau. The study of the geometry, kinematics and dynamics of the fault structures is of great significance for the formation and evolution of the Sanjiang Tethys orogenic belt, the Songpan-Ganzi orogenic belt and even the Yangtze plate. The fault structure in Litang area can be divided into three main faults from the plane geometry, namely, S-N fault, NW-SE fault and NE-SW fault. In this paper, the structural geometry of outcrop scale faults in Litang area has been observed by means of structural analysis method. The kinematics and dynamics of fault structures are analyzed and the deformation stages and regional tectonic evolution of faults in this area are preliminarily discussed. Since the Indosinian period, it is believed that the times of tectonic deformation of the Litang area can reach at least 6 times since the Indosinian period. The collision extrusion in the direction of NW-SE occurred early in the late curtain of Indosinian. Under the stress of this period, the cleavage of NW direction was formed. In this paper, the collision extrusion is regarded as the first tectonic deformation in the study area. The second phase of the maximum principal stress direction of NE-SW, occurred in the late Indosinian late curtain. Under the stress of this period, faults tend to be NE,SW on the break plane. A large number of quartz veins were filled in these fault zones late in the period. The third stage of the stress is tensional and the direction of the minimum principal stress is NNE-SSW,. Under the action of this stress in the middle and late Yanshanian period, the faults formed in the direction of NW have been stretched and expanded (at this time, quartz veins are formed). The stress direction of the fourth phase is E-W. Under the action of the stress in the middle period of Himalayan movement, the faults, joints and quartz veins formed in the early stage of the Himalayan movement are staggered to different degrees, and the faults of the current sub-NE strike are formed. The fifth stress direction is that NE-SW, under the action of early Pliocene stress, reacts on the faults, joints and veins in the early stage of the early Pliocene, and reinforces the faults along the NW strike. The direction of the sixth stage stress is unknown, and the formation time is the latest, about the early Pleistocene. The characteristic faults are multi-narrow (2-3cm), the belt is filled with a large number of fault gouges and fragments, and no quartz veins are filled. It is the multi-direction and multi-stage regional stress that leads to the fault structure in Litang area which has complicated geological structure.
【學(xué)位授予單位】：成都理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P542.3

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