卡拉麦里断裂带形成与演化规律
发布时间：2019-06-21 21:15
【摘要】：中亚造山带内东准噶尔地区北西西-南东东走向的大型卡拉麦里断裂带,为野马泉岛弧与哈尔里克岛弧之间的拼贴边界,沿卡拉麦里蛇绿岩带南缘出现。本文通过详细的野外与室内构造分析表明,卡拉麦里断裂带经历了四期构造活动。第一期为晚石炭世中期的脆-韧性右行走滑活动,剪切带内较软弱的板岩、砂板岩及浅变质凝灰岩内出现了密集的面理化带及张裂脉,而在泥灰岩内形成了糜棱岩。第二期为中二叠世晚期与三叠纪末的脆性逆冲活动,主要表现上盘向南的逆冲,叠加的逆冲断层一方面沿着早期陡立的剪切带面理发育,另一方面以较缓的产状切割剪切带。第三期为晚侏罗世的脆性左行走滑活动,叠加在早期脆-韧性剪切带与脆性逆冲断层之上。第四期为古近系初的脆性逆冲活动,并带有一定的右行分量。各类地质现象指示,晚石炭世中期卡拉麦里断裂带脆-韧性右行走滑剪切带的形成温度为250-300℃,与该区前二叠纪海相火山-碎屑岩的低级区域变质作用和紧闭褶皱同时发生。这期变质、变形也与区内海退同时发生。这些现象表明该剪切带是野马泉岛弧与哈尔里克岛弧斜向碰撞的结果,并指示早期卡拉麦里洋盆向北俯冲。中二叠世晚期卡拉麦里断裂带第二期逆冲活动是发生在该区后造山伸展之后,属于陆内变形,应为中亚造山带区域上一次中二叠世碰撞活动导致的。作为准噶尔盆地东北缘的一级边界断裂带,卡拉麦里断裂带控制和影响了准东地区盆地的形成和演化。准噶尔盆地形成于早二叠世的后造山伸展环境下。中二叠世,沿卡拉麦里断裂带及其南侧山前大规模向盆地的逆冲活动,构成了准噶尔盆地东北缘的前陆冲断构造带,盆地转化为前陆型盆地。随后在三叠纪期间,区内构造活动较弱,盆地进入稳定沉积的坳陷阶段。三叠纪末,沿卡拉麦里断裂带再次发生了逆冲活动。这两次逆冲活动造成了陆梁隆起上一系列北西西-南东东向凸起与凹陷相间的盆地格局。早-中侏罗世期间,准噶尔盆地又进入坳陷阶段。晚侏罗世,卡拉麦里断裂带在近东西向挤压背景下发生了左行走滑活动,同时该期区域挤压造成了盆内东部隆起一系列近南北向的逆冲断层与褶皱,从而呈现出近南北向凹陷与凸起相间的盆地格局。随后在早白垩世该盆地又进入稳定沉积的坳陷阶段。古近纪初,卡拉麦里断裂带在近南北挤压背景下又发生了逆冲活动,该期挤压造成了准噶尔盆地东部隆起内一系列近东西向的凹陷与凸起叠加在早期近南北向的凹陷与凸起之上,从而形成现今的“棋盘式”盆地构造格局。
[Abstract]:The large Karamaili fault zone in the east Junggar area of the Central Asian orogenic belt is the collage boundary between the Nomaquan island arc and the Harrik island arc, which appears along the southern margin of the Kalamaili ophiolite belt. Through detailed field and indoor structural analysis, it is shown that the Karamaili fault zone has experienced four stages of tectonic activity. The first stage is the brittle-ductile right-lateral strike-slip activity in the middle of the late Devonian. In the shear zone, there are weak slate, sand slate and shallow metaphorical tuff, and dense facified zones and tensioned veins appear, while mylonite is formed in the marl. The second stage is the brittle thrust activity in the late Middle Permian and the end of Triassic, which mainly shows the southward thrust of the upper plate. On the one hand, the superimposed thrust fault develops along the surface of the early steep shear zone, on the other hand, it cuts the shear zone with a slow occurrence. The third stage is brittle left strike-slip activity in late Jurassic, which is superimposed on the early brittle-ductile shear zone and brittle thrust fault. The fourth stage is the brittle thrust activity at the beginning of Paleogene, and has a certain right-lateral component. All kinds of geological phenomena indicate that the formation temperature of the brittle-ductile right walking slip shear zone in the Karamaili fault zone in the middle of late Carboniferous is 250 掳300 鈩，
本文编号：2504356
[Abstract]:The large Karamaili fault zone in the east Junggar area of the Central Asian orogenic belt is the collage boundary between the Nomaquan island arc and the Harrik island arc, which appears along the southern margin of the Kalamaili ophiolite belt. Through detailed field and indoor structural analysis, it is shown that the Karamaili fault zone has experienced four stages of tectonic activity. The first stage is the brittle-ductile right-lateral strike-slip activity in the middle of the late Devonian. In the shear zone, there are weak slate, sand slate and shallow metaphorical tuff, and dense facified zones and tensioned veins appear, while mylonite is formed in the marl. The second stage is the brittle thrust activity in the late Middle Permian and the end of Triassic, which mainly shows the southward thrust of the upper plate. On the one hand, the superimposed thrust fault develops along the surface of the early steep shear zone, on the other hand, it cuts the shear zone with a slow occurrence. The third stage is brittle left strike-slip activity in late Jurassic, which is superimposed on the early brittle-ductile shear zone and brittle thrust fault. The fourth stage is the brittle thrust activity at the beginning of Paleogene, and has a certain right-lateral component. All kinds of geological phenomena indicate that the formation temperature of the brittle-ductile right walking slip shear zone in the Karamaili fault zone in the middle of late Carboniferous is 250 掳300 鈩，
本文编号：2504356
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