摘要
本文提出了"兴蒙陆内造山带"的新概念(Xing-Meng Intracontinent Orogenic Belt,XMIOB),从大地构造、沉积建造、岩浆作用和变质作用等方面论述了XMIOB从晚古生代到中生代初的陆内伸展及陆内造山过程,为探讨晚古生代构造演化提供了新模式。根据对内蒙古中西部晚古生代构造格局的总体认识,可将XMIOB划分为五个构造单元即:早石炭世二连-贺根山裂谷带、晚石炭世陆表海盆地、早二叠世艾力格庙-二连伸展构造带、早-中二叠世盆岭构造带和晚二叠世索伦山-乌兰沟伸展构造带。晚石炭世末-二叠纪在兴蒙造山带基底上发育三期伸展构造:第一期见于内蒙古北部二连-艾力格庙地区,形成陆内裂谷盆地及其盆缘三角洲沉积,发育时代为302～298Ma;第二期在内蒙古中西部广泛分布,以隆起与凹陷相间分布的盆岭构造为特征,发育时代为290～260Ma;第三期见于内蒙古南部索伦山到温都尔庙乌兰沟一带,形成主动裂谷背景下的红海型小洋盆,发育时代为260～250Ma。晚古生代与伸展过程有关的岩浆活动可分四期:1)早石炭世贺根山期:以蛇绿岩为主,发育于具有前寒武纪古老基底和早古生代造山带年轻基底的陆壳伸展区; 2)晚石炭世达青牧场期:主要沿北造山带分布,以基性和酸性岩浆构成的双峰式侵火成岩为特征; 3)早二叠世大石寨期:形成的岩石种类多样,分布广泛,包括双峰式火山岩、双峰式侵入岩和碱性岩; 4)二叠纪末-三叠纪初索伦山期:形成陆缘型蛇绿岩或基性岩-超基性岩组合,产生于软流圈上涌造成的主动裂谷背景。兴蒙陆内造山带的构造变形可分为两期,第一期为晚古生代地层大范围褶皱变形,造成盆-岭构造带的缩短;第二期为沿盆-岭构造的边界强烈剪切变形,产生向东逃逸的挤出构造,其构造背景是北部蒙古-鄂霍茨克造山带和南部大别-秦岭中央造山带的远距离效应引起的被动�
In this paper,a new c0ncept of＂Xing-Meng Intracontinent Orogenic Belt＂（ XMIOB） is suggested. The Late Paleozoic to Early Mesozoic intra-continental extension and orogenic evolution of the XMIOB are synthesized from the perspective of tectonics,sedimentary formation,magmatism and metamorphism,which provides useful insight into the Late Paleozoic tectonic evolution of XMIOB. According to the Late Paleozoic tectonic framework of mid-western Inner Mongolia,five tectonic units can be recognized,including the Early Carboniferous Erenhot-Hegenshan rift belt（ C1 EHR）,the Late Carboniferous inland sea basin（ C2 IS）,the Early Permian Airgin Sum-Erenhot extensional belt（ P1 AEEB）,the Early-Middle Permian basin-range belt（ P1-2 BRB）,and the Late Permian Solonker-Ulan valley extensional belt（ P3 SWEB）. From the Late Carboniferous to Permian,the extensional structures in the XMIOB can be clustered into three stages. The first stage can be found in Erenhot-Airgin Sum area,northern Inner Mongolia,in form of intracontinental rift basin and its marginal delta deposits during 302 - 298 Ma. The second stage is characterized by basin-range structure during 290 - 260 Ma,which are widely distributed in mid-western Inner Mongolia. The third stage can be observed at Solon Obo,southern Inner Mongolia and Ulan valley in the south of Ondor Sum,representing a Red Sea-type oceanic basin in active rifting zone during 260 - 250 Ma. The extension-related magmatism during the Late Paleozoic includes four phases： 1） The Early Carboniferous Hegenshan ophiolite phase,which developed on the basement of pre-Cambrian or Early Paleozoic orogenic belt,reflects deep magmatic process in the continent crust; 2） The igneous rock originated from the Late Carboniferous Daqing pasture phase are widely distributed along the north orogenic belt,characterized by bimodal intrusive and volcanic rocks that mainly consist of mafic and felsic magma; 3） The Early Carboniferous Dashizai phase formed various rocks including bimodal volc
作者
徐备
王志伟
张立杨
王智慧
杨振宁
贺跃
XU Bei;WANG ZhiWei;ZHANG LiYang;WANG ZhiHui;YANG ZhenNing;HE Yue(Key Laboratory of Regional Geology and Mineralization,Hebei GEO University,Shijiazhuang 050031,China;College of Resources,Hebei GEO University,Shijiazhuang 050031,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2018年第10期2819-2844,共26页
Acta Petrologica Sinica
基金
科技部国家重点研发计划(2017YFC0601302)
国家自然科学基金项目(41672214)联合资助
关键词
兴蒙陆内造山带
兴蒙造山带
晚古生代
伸展构造
构造演化
Xing-Meng Intracontinent Orogenic Belt
Xing-Meng Orogenic belt
Late Paleozoic
Extensional structure
Tectonic evolution
