内蒙古巴拉格歹地区构造混杂岩带中浊积岩、震积岩特征及意义——以内蒙古哈拉黑等八幅1:5万区域地质调查为例  

The petrological characteristics and tectonic implications of turbidite and seismite in Balagedai tectonic melange belt,Inner Mongolia:Take regional geological survey scaled 1:50000 in Halahei area,Inner Mongolia as an example

作　　者：张庆奎 杨宾 邵学峰 陈树良 赵明远 吕凤祥 ZHANG Qingkui;YANG Bin;SHAO Xuefeng;CHEN Shuliang;ZHAO Mingyuan;Lü Fengxiang(Liaoning Provincial Institute of Geological Exploration,Dalian 116100,Liaoning,China)

机构地区：[1]辽宁省地质勘查院,辽宁大连116100

出　　处：《地质通报》2018年第9期1731-1735,共5页Geological Bulletin of China

基　　金：中国地质调查局项目<内蒙古1:5万哈拉黑等八幅区域地质矿产调查>(编号:DD20160048-08)

摘　　要：浊积岩为具有鲍马序列的古海沟沉积,其部分沉积物与古海沟地震密切相关,由于岛弧外弧海沟地质构造复杂,洋板块俯冲及火山岩的喷发,地震活动强烈、频繁,沉积岩在成岩过程不断受到地震扰动,形成具有地震活动特点的震积岩。通过对巴拉格歹地区构造混杂岩带中浊积岩、震积岩的研究,识别出浊积岩系的具递变层理的槽模、沟模等冲刷铸模,包卷层理构造及最顶部黑色粉砂质泥岩段;识别出震积岩系的液化脉、地震震碎角砾岩、滑塌角砾岩、震褶岩-卷曲、纹层状、阶梯状断层构造等,建立并确认浊积岩、地震岩识别标志,恢复古地理构造环境,认为原划分的大石寨组应该解体,应为一套弧前盆地古海沟浊积岩沉积。结合浊积岩中的火山岩、基性岩及区域上化石山发现的超基性岩,初步确认,在测区浊积岩与岛弧火山岩、洋壳沉积物受板块碰撞拼接作用,由一系列逆冲断裂将上述各种块体构造就位在一起,形成构造混杂岩,为二连-贺根山缝合带在本区东延问题提供了资料。The turbidite is the ancient trench sediments with Bouma series. And part of the sediment is closely related to the ancient trench earthquake. Due to oceanic plate subduction and volcanic eruption, the seismic activities are intense and frequent at the trench. The Sedimentary rocks are constantly disturbed by earthquakes during diagenetic process at this area. So, the seismites recording seismic activities are formed. By studying the turbidite and seismite in Balagedai tectonic melange belt, we recognize the turbidite sequence and the seismite sequence. The turbidite sequence includes flushing molds such as ditch mold and flute cast with graded bedding, convolute bedding, and the black silty mudstone at the top sequence. The seismite sequence includes fluidized vein, shattered breccia, slump breccia, seismic crimp, laminar or stepped fault, etc. Then we establish the identification marks of turbidite and seismite rocks. Furthermore, we restored the paleotectonic environment of Dashizhai Formation at study area. And the former Dashizhai Formation divided by predecessor should be broken up. Dashizhai Formation is the turbidite sediment at the ancient trench in the arc-front basin. Considering the volcanics, basic rocks or ultrabasic rocks in Huashi Hill in the turbidite, we get the conclusion that,due to plate collision, the turbidite, arc volcanic rocks and oceanic sediments are bunched together by a series of thrust faults. So thetectonic melange is formed. This provide evidence that Erlian-Heihe suture zone extends eastern to the study area.

关 键 词：巴拉格歹 浊积岩 震积岩 二连-贺根山缝合带 

分 类 号：P588.2[天文地球—岩石学]