CAJ | 학술논문

秭归褶皱带位于大巴山逆冲带与雪峰山逆冲带叠合部位，总体呈现穹窿-盆地型式，是构造复合、联合作用的结果，记录了大巴山逆冲带与雪峰山逆冲带两者相互作用的重要信息，是研究构造复合和联合过程的理想区域。本文通过对秭归褶皱带秭归向斜、巴东复向斜和香龙山背斜的野外调查，对褶皱枢纽、相关断层、节理等进行详细构造解析，理清了先后叠加关系，在此基础上进行了构造分期和配套，对变形期古构造应力场进行了恢复重建。结果表明秭归褶皱带晚侏罗世-早白垩世经历三期构造变形：D1期以近EW向的秭归向斜和香龙山背斜为代表，秭归向斜为轴面近直立的开阔圆弧状，香龙山背斜呈轴面近直立的箱状，相关逆冲断层具由北向南逆冲的特点，可能与大巴山由NE向SW逆冲作用有关。D2期秭归向斜叠加近SN 向枢纽，呈锅状，香龙山背斜东段发育鼻状的五龙背斜，褶皱带呈穹窿-盆地型。与向斜相关的水田坝断裂带向SEE逆冲，主压应力场呈NWW-SEE近平行的束状。该期变形可能与雪峰山逆冲带向NW逆冲过程中受到黄陵背斜阻挡有关。D3期秭归向斜近SN 向枢纽向南西弯曲，巴东复向斜呈NW凸出弧形，香龙山背斜西端叠加NE-SW向构造形迹。主压应力场总体向NW发散。该期变形可能与雪峰山逆冲带向NW逆冲推挤有关。上述构造分析表明，向SW逆冲的大巴山逆冲带先影响鄂西地区，之后向NW逆冲推挤的雪峰山逆冲带扩展至该地区，形成复合关系。区域构造与地层关系分析表明D1-D3形成于J3-K1，因此秭归褶皱带是大巴山逆冲构造带向SW叠瓦逆冲并与指向NW的雪峰山逆冲带复合叠加的结果，表明上扬子地区在J3-K1经历了分阶段复合叠加的过程，即前期受到大巴山逆冲带近SN构造作用影响，后期经历向N W逆冲推挤的雪峰山逆冲带N W-SE向构造叠加。秭歸褶皺帶位于大巴山逆遲帶與雪峰山逆遲帶疊閤部位，總體呈現穹窿-盆地型式，是構造複閤、聯閤作用的結果，記錄瞭大巴山逆遲帶與雪峰山逆遲帶兩者相互作用的重要信息，是研究構造複閤和聯閤過程的理想區域。本文通過對秭歸褶皺帶秭歸嚮斜、巴東複嚮斜和香龍山揹斜的野外調查，對褶皺樞紐、相關斷層、節理等進行詳細構造解析，理清瞭先後疊加關繫，在此基礎上進行瞭構造分期和配套，對變形期古構造應力場進行瞭恢複重建。結果錶明秭歸褶皺帶晚侏囉世-早白堊世經歷三期構造變形：D1期以近EW嚮的秭歸嚮斜和香龍山揹斜為代錶，秭歸嚮斜為軸麵近直立的開闊圓弧狀，香龍山揹斜呈軸麵近直立的箱狀，相關逆遲斷層具由北嚮南逆遲的特點，可能與大巴山由NE嚮SW逆遲作用有關。D2期秭歸嚮斜疊加近SN 嚮樞紐，呈鍋狀，香龍山揹斜東段髮育鼻狀的五龍揹斜，褶皺帶呈穹窿-盆地型。與嚮斜相關的水田壩斷裂帶嚮SEE逆遲，主壓應力場呈NWW-SEE近平行的束狀。該期變形可能與雪峰山逆遲帶嚮NW逆遲過程中受到黃陵揹斜阻擋有關。D3期秭歸嚮斜近SN 嚮樞紐嚮南西彎麯，巴東複嚮斜呈NW凸齣弧形，香龍山揹斜西耑疊加NE-SW嚮構造形跡。主壓應力場總體嚮NW髮散。該期變形可能與雪峰山逆遲帶嚮NW逆遲推擠有關。上述構造分析錶明，嚮SW逆遲的大巴山逆遲帶先影響鄂西地區，之後嚮NW逆遲推擠的雪峰山逆遲帶擴展至該地區，形成複閤關繫。區域構造與地層關繫分析錶明D1-D3形成于J3-K1，因此秭歸褶皺帶是大巴山逆遲構造帶嚮SW疊瓦逆遲併與指嚮NW的雪峰山逆遲帶複閤疊加的結果，錶明上颺子地區在J3-K1經歷瞭分階段複閤疊加的過程，即前期受到大巴山逆遲帶近SN構造作用影響，後期經歷嚮N W逆遲推擠的雪峰山逆遲帶N W-SE嚮構造疊加。
자귀습추대위우대파산역충대여설봉산역충대첩합부위，총체정현궁륭-분지형식，시구조복합、연합작용적결과，기록료대파산역충대여설봉산역충대량자상호작용적중요신식，시연구구조복합화연합과정적이상구역。본문통과대자귀습추대자귀향사、파동복향사화향룡산배사적야외조사，대습추추뉴、상관단층、절리등진행상세구조해석，리청료선후첩가관계，재차기출상진행료구조분기화배투，대변형기고구조응력장진행료회복중건。결과표명자귀습추대만주라세-조백성세경력삼기구조변형：D1기이근EW향적자귀향사화향룡산배사위대표，자귀향사위축면근직립적개활원호상，향룡산배사정축면근직립적상상，상관역충단층구유북향남역충적특점，가능여대파산유NE향SW역충작용유관。D2기자귀향사첩가근SN 향추뉴，정과상，향룡산배사동단발육비상적오룡배사，습추대정궁륭-분지형。여향사상관적수전패단렬대향SEE역충，주압응력장정NWW-SEE근평행적속상。해기변형가능여설봉산역충대향NW역충과정중수도황릉배사조당유관。D3기자귀향사근SN 향추뉴향남서만곡，파동복향사정NW철출호형，향룡산배사서단첩가NE-SW향구조형적。주압응력장총체향NW발산。해기변형가능여설봉산역충대향NW역충추제유관。상술구조분석표명，향SW역충적대파산역충대선영향악서지구，지후향NW역충추제적설봉산역충대확전지해지구，형성복합관계。구역구조여지층관계분석표명D1-D3형성우J3-K1，인차자귀습추대시대파산역충구조대향SW첩와역충병여지향NW적설봉산역충대복합첩가적결과，표명상양자지구재J3-K1경력료분계단복합첩가적과정，즉전기수도대파산역충대근SN구조작용영향，후기경력향N W역충추제적설봉산역충대N W-SE향구조첩가。
Zigui fold belt is located in the congruent part of Dabashan and Xuefengshan thrust belt,which is dome and basin,and is the result of the tectonic compounding and combination.Because Zigui fold belt recorded the important imformation reflecting the interaction of Dabashan and Xuefengshan thrust belt,it is the ideal site of studying on the compounding and combination process.This paper has a field research on Zigui sycline,Badong synclinorium and Xianglongshan anticline in Zigui fold belt,whose hinge of fold,fold related fault and joints are been structural analysis in detail,then we determine the superposition relation among them.Based on those,we distinguished different deformation through matching by stages,then reconstruct the paleo-stress-field during deformation stage.The result shows that Zigui fold belt experienced three stage deformation during J3-K1:D1 is that the Zigui sycline and Xianglongshan anticline was nearly EW.Zigui sycline was extensive round with the nearly upright axe and Xianglongshan anticlne was box with the upright axe.The related thrust fault was characteristic by thrusting from north to south. Those features may be related to Dabashan thrusting from NE to SW.D2 is that Zigui sycline was superposition with hinge of nearly SN,then the sycline showed like a pan and the Wulong anticline developed in the east of Xianglongshan anticline.The fold belt was dome and basin.The Shuitianba fault related with Zigui sycline thrusted to SEE.The major stress field was parallel bunchiness.And the deformation may be related with the Xuefengshan thrust belt whcih was barriered by Huangling anticline when thrusting to NW.D3 is that the nearly SN hinge of Zigui sycline bent to SW,and Badong synclinorium was arc been convex to NW,and the western segment of the Xianglongshan anticline was superposition by the structural features.The major stress field was generally divergent to NW.This deformation may be connected with that Xuefengshan thrusted to NW.Those sructural analysises show that Dabashan belt thrusting to NW firstly influenced the western Hubei,then Xuefenshan belt thrusted and broached to NW extended the region,that was a compounding relation.By analysis of the regional tectonic and stratum trelationship,we could have a conclusion that the deformaion D1-D3 deformed during J3 to K1 .As a result, Zigui fold belt which is prduct by compounding superposition with the Dabashan thrust belt thrusting to SW and Xuefengshan thrust belt to NW,that shows upper Yangzi region experienced compounding superposition process by stages during J3 to K1 ,that is,upper Yangzi region was sujected to nearly SN tectonic process by Dabashan thrust belt precviously,then suffered from NW-SE structural compounding superposition by Xuefengshan thrust NW.