地质论评
地質論評
지질론평
GEOLOGICAL REVIEW
2015年
1期
79-94
,共16页
宋利宏%朱光%顾承串%翟明见
宋利宏%硃光%顧承串%翟明見
송리굉%주광%고승천%적명견
中亚造山带%卡拉麦里断裂带%脆-韧性剪切带%逆冲断层%造山过程
中亞造山帶%卡拉麥裏斷裂帶%脆-韌性剪切帶%逆遲斷層%造山過程
중아조산대%잡랍맥리단렬대%취-인성전절대%역충단층%조산과정
Central Asian Orogenic Belt%Kalamaili fault zone%brittle-ductile shear zone%thrusts%orogenic processes
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,这一倾向北北东的断裂带在造山期分别经历了脆—韧性右行走滑剪切和脆性逆冲活动。其脆—韧性剪切带在较软弱的板岩、砂板岩及浅变质凝灰岩内造成了密集的面理化带及张裂脉,而在泥灰岩内形成了糜棱岩。该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同时发生。该断裂带的第二期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。各类地质现象指示,其脆—韧性右行走滑活动发生于晚石炭世中期,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。该断裂带的第二期逆冲活动发生于中二叠世,出现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。
中亞造山帶內東準噶爾地區北西西—南東東走嚮的大型卡拉麥裏斷裂帶,為野馬泉島弧與哈爾裏剋島弧之間的拼貼邊界,沿卡拉麥裏蛇綠巖帶南緣齣現。本文通過詳細的野外與室內構造分析錶明,這一傾嚮北北東的斷裂帶在造山期分彆經歷瞭脆—韌性右行走滑剪切和脆性逆遲活動。其脆—韌性剪切帶在較軟弱的闆巖、砂闆巖及淺變質凝灰巖內造成瞭密集的麵理化帶及張裂脈,而在泥灰巖內形成瞭糜稜巖。該剪切帶的形成溫度為250~300℃,與該區前二疊紀海相火山—碎屑巖的低級區域變質作用同時髮生。該斷裂帶的第二期脆性逆遲活動主要錶現上盤嚮南的逆遲,疊加的逆遲斷層一方麵沿著早期陡立的剪切帶麵理髮育,另一方麵以較緩的產狀切割剪切帶。各類地質現象指示,其脆—韌性右行走滑活動髮生于晚石炭世中期,是野馬泉島弧與哈爾裏剋島弧斜嚮踫撞的結果,併指示早期卡拉麥裏洋盆嚮北俯遲。該斷裂帶的第二期逆遲活動髮生于中二疊世,齣現在該區後造山伸展之後,屬于陸內變形,應為中亞造山帶區域上一次中二疊世踫撞活動導緻的。
중아조산대내동준갈이지구북서서—남동동주향적대형잡랍맥리단렬대,위야마천도호여합이리극도호지간적병첩변계,연잡랍맥리사록암대남연출현。본문통과상세적야외여실내구조분석표명,저일경향북북동적단렬대재조산기분별경력료취—인성우행주활전절화취성역충활동。기취—인성전절대재교연약적판암、사판암급천변질응회암내조성료밀집적면이화대급장렬맥,이재니회암내형성료미릉암。해전절대적형성온도위250~300℃,여해구전이첩기해상화산—쇄설암적저급구역변질작용동시발생。해단렬대적제이기취성역충활동주요표현상반향남적역충,첩가적역충단층일방면연착조기두립적전절대면리발육,령일방면이교완적산상절할전절대。각류지질현상지시,기취—인성우행주활활동발생우만석탄세중기,시야마천도호여합이리극도호사향팽당적결과,병지시조기잡랍맥리양분향북부충。해단렬대적제이기역충활동발생우중이첩세,출현재해구후조산신전지후,속우륙내변형,응위중아조산대구역상일차중이첩세팽당활동도치적。
The large-scale NWW-striking Kalamaili fault zone in the eastern Junggar area is situated along the collision boundary between the Yemaquan and Harlik arcs,and along the southern margin of the Kalamaili ophiolite zone.On the basis of detailed field investigation and structural analysis,it is demonstrated that the NNE-dipping Kalamaili fault zone is subjected to earlier brittle—ductile dextral shearing and later brittle thrusting in the orogenic procesess.The more easily deformed rocks in the Kalamaili brittle—ductile shear zone,such as slate,sandy slate, and low-grade tuff,show densely foliation and tensile veins,and marls is deformed into mylonite.Deformation temperatures of the Kalamaili brittle—ductile shear zone is 250 ~300℃,and the shear zone development and regional low-grade metamorphism of pre-Permian volcanic—sedimentary rocks in this area occur at the same period. The second phase activity of the Kalamaili fault zone is top-to-the-south thrusting.The thrusts formed along the foliation of the earlier shear zone,or truncated the earlier shear zone.A variety of geological phenomena show that the Kalamaili brittle—ductile dextral shearing took place in the middle Late Carboniferous.The shear zone results from the oblique collision between Yemaquan arc and Harlik arc,which suggests that the Kalamaili oceanic plate subducted northwards.The Kalamaili brittle thrusts formed in the Middle Permian and belong to intracontinental deformation happening after the post-collisional extension of the area.This phase of deformation should be related to the Middle Permian collision within the Central Asian Orogenic Belt .