【作者】 刘兵；

【导师】 刘永江；

【作者基本信息】 吉林大学 ， 构造地质学， 2014， 博士

【摘要】 东北地区发育的晚古生代海相沉积建造蕴藏着十分丰富的油气资源，是寻找海相油气勘探新区新领域最有前景的区域，对晚古生代海相沉积建造油气资源的评价必须考虑其形成的大地构造背景，因此本论文紧密围绕与东北地区油气勘探新领域研究有关的区域构造格架和构造演化研究，通过对内蒙古东部大兴安岭地区晚古生代地层沉积特征、构造特征、岩相-古地理特征以及年代学的研究来讨论大兴安岭地区晚古生代构造演化，为东北地区晚古生代海相沉积建造形成背景和油气资源评价提供重要的依据。大兴安岭地区包括额尔古纳地块、兴安地块、松嫩地块（简称北部地块群），以贺根山-嫩江-黑河缝合带为界，西北部主要包括额尔古纳地块、兴安地块，归属为兴安地层区，该区晚古生代地层多呈北北东向展布，主要包括下-中泥盆统泥鳅河组、中-上泥盆统大民山组、上泥盆统安格尔音乌拉组、下石炭统红水泉组、上石炭统-下二叠统宝力高庙组、中二叠统哲斯组、上二叠统林西组、下三叠统老龙头组；贺根山-嫩江-黑河缝合带东南部松嫩地块归属为内蒙古草原地层区，该区的上古生界自下而上有上志留统-下泥盆统西别河组、上石炭统本巴图组、上石炭-下二叠统阿木山组、下二叠统寿山沟组、下二叠统大石寨组、中二叠统哲斯组、上二叠统林西组、下三叠统老龙头组。根据额尔古纳地块、兴安地块、松嫩地块晚古生代地层对比及地层特征分析，初步将大兴安岭地区划分为三个构造层：泥盆纪-早石炭世构造层、晚石炭世-中二叠世构造层、晚二叠世-早三叠世构造层。泥盆纪-早石炭世海相沉积与下伏志留纪浅海相沉积为连续沉积，与上覆晚石炭世沉积为不整合关系；晚石炭世沉积明显具有北部为陆相、南部为海相的沉积特征；晚二叠世-早三叠世为陆相沉积。野外构造特征显示，大兴安岭地区泥盆纪-早石炭世构造应力场为NW-SE向挤压，构造样式主要为宽缓的褶皱；晚石炭纪-中二叠世构造应力场表现为NW-SE向拉张，总体表现为宽缓的褶皱，局部劈理发育；晚二叠世-早三叠世为近S-N向的挤压构造应力场，研究区南部构造置换十分强烈，片理发育，紧闭褶皱发育，北部变形较弱，变形为宽缓褶皱变形，总体表现为南强北弱。早石炭世古地理格局呈现南陆北海的构造格局，沉积中心主要分布于海拉尔伊敏和额尔古纳一带；晚石炭世构造沉积环境与早石炭世截然不同，以贺根山-嫩江-黑河一线为界呈现南海北陆的构造格局，其重要特征是整个大兴安岭地区隆升为古陆，标志着额尔古纳地块、兴安地块、松嫩地块统一盖层的形成；早二叠世继承了南海北陆的构造格局，主要出露地层为海相的大石寨组和陆相的宝力高庙组；中二叠世的沉积环境更为明显地继承了早二叠世的构造古地理格局，但火山活动明显减弱，海盆地进一步加深，反映出盆地进入了整体沉降演化阶段，沉积中心的南界大致沿林西-扎鲁特旗一线，北界沿霍林郭勒-突泉一线，中二叠世海盆地呈北部较窄，向南敞开喇叭状，其南界大致在西拉木伦河沿线；晚二叠世沉积古地理格局发生重大变化，大兴安岭地区整体由海相转变为陆相沉积，基本上沿着中二叠世海相盆地沉积中心形成了一个近东西向的陆相沉积中心。综合研究区晚古生代地层沉积特征、构造特征、岩相-古地理特征以及碎屑锆石U-Pb测年结果，将大兴安岭地区划分为3个演化阶段：（1）内蒙东部额尔古纳地块与兴安地块于寒武纪时期沿新林-喜桂图缝合带完成拼合，额尔古纳-兴安地块与松嫩地块之间发育晚泥盆世-早石炭世的沟-弧-盆体系，可能表明额尔古纳-兴安地块东部边界为活动陆缘演化阶段，其缝合带位置沿贺根山-嫩江-黑河一线展布，于早石炭末完成拼合，形成统一的“北部地块群”；（2）晚石炭世进入碰撞后伸展阶段，一直延续到中二叠世；（3）晚二叠世-早三叠世为“北部地块群”与华北板块碰撞拼贴阶段，最终缝合带应为西拉木伦河缝合带，此后转入陆内演化阶段，此次汇聚作用的构造响应主体表现为研究区南部发育EW向展布的相对紧闭的褶皱和逆冲断裂构造。更多还原

【Abstract】 The marine sediments are widely developed in the NE China, and considered to bevery rich in oil and gas resources, therefore become the most promising new areas for theoil exploration. In order to better evaluating the late Paleozoic marine sedimentary oil andgas resource, a reliable tectonic setting is anxiously required. In the paper, we are closelyfocusing on the study of regional tectonic framework and tectonic evolution of the easternInner Mongolian. On the basis of the researches of the late Paleozoic sedimentarycharacteristics, structural characteristics, lithological-paleogeography and geochronologyresearches, to discuss the late Paleozoic tectonic evolution of the eastern Inner Mongolia,further to provide an important basis for the late Paleozoic marine sedimentarybackground, even for the oil and gas resource evaluation.The Great Xing’an Ranges in eastern Inner Mongolia consists of the Ergun massif, theXing’an massif and the Songnen massif (the combined block is termed as ‘North block’ inthe paper). The paleogeostratigraphic study suggests that the eastern Inner Mongolia isdivided into two stratigraphic areas bounded by the Hegenshan-Nenjiang-Heihe suturezone, e.g., Xing’an stratigraphic area including the Ergun and Xing’an massifs, and InnerMongolia grass stratigraphic area including the Songnen massif. The late Paleozoic stratadeveloped in the Xing’an stratigraphic area are distributed in NNE-trending direction, andthey are composed of the early-mid Devonain Niquhe formation, the mid-late DevonainDaminshan formation, the late Devonian Angeeryinwula formation, the early Carboniferous Hongshuiquan formation, the late Carboniferous to early PermianBaoligaomiao formation, the mid Permian Zesi formation, the late Permian Linxiformation and the early Triassic Laolongtou formation. The Paleozoic strata in the InnerMongolia grass stratigraphic area are the late Silurian to early Devonian Xibieheformation, the late Carboniferous Benbatu formation, the late Carboniferous to earlyPermian Amushan formation, the early Permian Shoushangou and Dashizhai formations,the mid Permian Zesi formation, the late Permian Linxi formation and the early TriassicLaolongtou formation.According to the characters of the Paleozoic strata developed in the Ergun, Xing’anand Songnen massifs, and their comparison, the division of the tectonic sequences isfirstly determined as three stages, e.g., Devonian-early Carboniferous tectonic sequence,late Carboniferous-mid Permian tectonic sequence and late Permian-early Triassic tectonicsequence. The Devonian-early Carboniferous strata is characterized by the marinesedimentary, and is conformity with under layered Silurian marine strata and unconformitywith the upper layered late Carboniferous strata, respectively. The late Carboniferousstrata in the study area significantly shows that the north part is continental sedimentary,whereas the south part is marine sedimentary. The late Permian strata is represented by thecontinental sedimentary.In order to better understanding the direction of the stress field in the differenttectonic sequences, the detailed measurements of structural occurrences have been done inthe field investigation. The results show that,(1) the compressive stress direction of theDevonian-early Carboniferous tectonic sequence was NW-SE trending, and the structuralpattern was represented by the broad folds;(2) the stress field was characterized by theextensive stress during the late Carboniferous-mid Permian tectonic sequence, with thedirection of NE-SW trending, and the broad folds and cleavages were widely developed inthe study area; and (3) the compressive stress direction of the late Permian-early Triassicchanged to S-N trending, structural transpositions were well performed in the south part of the study area, in where the schistosity and tight folds were also well developed.The lithological-paleogeographical maps of the study area suggest that,(1) thepaleogeography in early Carboniferous period was the character of continent in the southand sea/ocean in the north. Moreover, the deposit center is located closed to the Yiming inHailar and the Ergun areas;(2) the paleogeography in the late Carboniferous was differfrom former, and showed characters of continent in the north and sea/ocean in the south.In this period, the entire eastern Inner Mongolia uplifted to the surface, indicating theErgun, Xing’an and Songnen massifs had amalgamated as an uniformed block (so called‘North block’);(3) in early Permian, the paleogeography was similar to that of lateCarboniferous, and the Dashizhai marine sediments and the Baoligaomiao continentalsediments were deposited;(4) the paleogeography was not changed till to the mid Permianperiod, but the volcanic activities decreased obviously. The marine basin became more andmore deep, implying the basin underwent settlement stage. The deposit center wasconstrained by the south boundary roughly along the Linxi-Zhalute areas and northboundary along the Huolinguole-Tuquan areas;(4) the paleogeography of late Permiansignificantly changed, showing the continental deposits instead of former marine depositsin the eastern Inner Mongolia, and newly formed a near east-west continental depositcenter along the mid Permian marine deposit center.Combining this study and previous studies, including characteristics of the latePaleozoic strata, structural characteristics, lithological-paleogeography and detrital zirconU-Pb dating results obtained from the eastern Inner Mongolia, we concluded three tectonicevolutional stages, e.g.(1) the Ergun and Xing’an massifs amalgamated in Cambrianalong the suture zone of Xinlin-Xigutu belt. Subsequent to this period, the subduction andcollision between the Ergun-Xing’an block and Songnen massif took place during lateDevonian to early Carboniferous. At the beginning of the subduction process, a‘trench-arc-basin’ system was existed. The final collision was complete at end of earlyCarboniferous along the Hegenshan-Nenjiang-Heihe suture zone. An uniformed block of ‘North block’ was then formed, and underwent the subsequent tectonic evolution together;(2) the post-collision between the Ergun-Xing’an block and Songnen massif was lasteduntil to mid Permian, the study area was therefore belong to the extensive environment;(3)the subduction and collision between the ‘North block’ and North China Craton took placeaccompanied with the closure of Paleo-Asian Ocean, and the final collision was completeat late Permian to early Triassic along the Xar Moron River zone. The study area was thentransferred to the continental evolutional stage, the role of the structural response of themain convergence performed related to the EW trending tight folds and thrusts.更多还原