摘要
运动速度与构造样式之间或许存在一定的内在联系,充分认识它们之间的关系对理解自然界的构造变形演化过程具有十分重要意义。为此,笔者等结合野外露头观察,开展了脆—韧性结构条件下,不同的变形速率对褶皱—冲断带的构造样式影响的物理模拟测试分析。结果表明:(1)高应形速率形成以前冲为主的构造样式,中等应形速率形成以前冲和后冲为主的构造样式,而低应形速率则形成以纯后冲为主的构造样式。(2)构造变形样式的差异主要是物质内部的应力状态所决定的:褶皱—冲断带的根带,脆性层剪应力大于基底韧性层的剪应力,形成以前冲断裂为主的构造样式;而褶皱—冲断带的中段和前缘地区,脆性层的剪应力和基底韧性层的剪应力较为接近,形成后冲和对称性冲起构造为主。(3)构造地质体的变形速率很可能决定了其存在的物质状态。葡萄牙南部滨岸带的布丁构造和北美卡斯卡底古陆的纯后冲构造等特殊的构造样式极有可能是在差异的变形速率下形成。
Objective:There may be a closed relationship between the velocity and the structural style.It is an important material attribute,which is of great significance to understand the deformation and evolution process of nature.Methods:Therefore,combined with field outcrop observation,this study carried out physical simulation test and analysis of different deformation rates of fold —thrust-belt.Results:The results show that:(1)High velocity forms a structural style dominated by forward thrust faults,medium velocity forms a structural style dominated by forward thrust fault and backward thrust fault,while low velocity forms a structural style dominated by pure backward thrust fault.(2)The difference of structural deformation patterns is mainly determined by the internal stress state of the rock:the forward thrust fault was developed in the hinterland of the fold-and-thrust belt,and the shear stress of the brittle layer is greater than that of the basal ductile layer,while in the middle and front domains,the shear stress of the brittle layer is close to that of the basal ductile layer,mainly forming back thrust and symmetrical pop-up thrust structures.(3) The deformation rate of tectonic geological body may determine its existing state.Conclusions:The pudding structure of the coastal area in the south of Portugal and the dominating back thrusts in Cascadian-type margins in North America are likely to be formed under different deformation rates.
作者
何文刚
李生红
刘重庆
赵远雯
骆忧
HE Wengang;LI Shenghong;LIU Chongqing;ZHAO Yuanwen;LUO You(College of Engineering and Technology,Zunyi Normal University,Zunyi,Guizhou,563006,China;Instituto Dom Luiz,Faculdde de Ciencias,University de Lisboa,Lisboa,1749-016,Portugal;School of Geology and Geomatics,Tianjin Chengjian University,Tianjin,300384,China)
出处
《地质论评》
CAS
CSCD
北大核心
2023年第2期469-480,共12页
Geological Review
基金
国家留学基金委资助项目(编号:201908520019)
贵州省科技厅资助项目(编号:黔科合基础-zk[2022])
遵义师范学院资助项目(编号:黔教合KY[2022]014号)的成果。
关键词
变形速率
构造样式
演化过程
褶皱—冲断带
物理模拟
deformation velocity
structural style
evolution process
fold-and-thrust belt
analogue modelling
