龙门山前陆盆地充填序列

文章以构造地层学和层序地层学相结合的综合地层学分析方法作为分析龙门山前陆盆地的基础，以不整合面和其对应面作粉割盆地充填序列的基本界面，并按不整合面的规模和性质，将龙门山前陆盆地充填序列分割为６个构造层序和１４个层序，初步查明了龙门山前陆盆地充填序列和沉积体系三维空间配置模式及其在时间上的演变。建立了龙门山前陆盆地地层格架和充填模式。     

前陆盆地层序地层学研究简介

前陆盆地层序地层学是将层序地层学理论应用于构造活动的前陆盆地分析的一个特例。前陆盆地三级层序成因并非受全球统一的海平面变化控制，而是与盆缘造山带区域本报特约记者运动、盆内沉积作用和相对海平面变化的联合作用有关，代表了前陆分地一个成盆期的不同发育阶段。层序界面是相对海平面下降和区域构造隆的联合作用面。在盆地演化的不对称沉降阶充填阶段，邻造山带区为低水位浊积扇沉积层序；远离造山带区，低水位体系域不发育     

前陆盆地层序地层学研究现状及进展

本文主要介绍了前陆盆地层序地层学的研究现状及急待解决的问题。前陆盆地层序地层学是将层序地层学的理论应用于构造活动区盆地分析的一个特例；前陆盆地二级构造层序代表了盆地不同成盆期的产物；前陆盆地的三级构造层序的成因并非受全球统一海平面变化控制，而与盆缘造山带的区域构造活动、盆内沉积作用和相对海平面变化的联合作用有关，是一个成盆期不同发育阶段的产物；前陆盆地地层的层序反映了前陆盆地构造演化史为一个多旋回的沉积－构造演化史。     

皖南地区加里东期前陆盆地层序地层特征

皖南地区从晚奥陶世-志留纪末以来，由于受加里东运动的影响．造成盆地性质由沉积盆地突然转变为构造盆地，形成冲断带和前陆盆地。扬子东南边缘从被动大陆边缘沉积盆地演化成为前陆盆地，是在挤压收缩构造背号下铸就了特有的古地理构造和演化特征，为典型的前陆盆地充填和向上变浅序列。通过对前陆盆地内露头层序地层的研究，将中奥陶统至志留纪系划分为1个二级沉积层序，以海平面相对变化和沉积物的转变进一步划分成3个三级层序。详细分析了每个沉积层序各体系域的特征。区内的晚奥陶世-志留纪总体为一变深往上又变浅的沉积层序。     

中生代羌塘前陆盆地充填序列及演化过程

中生代羌塘前陆盆地位于青藏高原巨型造山带内 ,夹于金沙江缝合带与班公湖—怒江缝合带之间 ,是一个与两侧缝合带逆冲作用相关的沉积盆地 ,由羌北盆地 (对应于金沙江缝合带 )、羌南盆地 (对应于班公湖—怒江缝合带 )和中央隆起带构成 ,其中中央隆起是北部前陆盆地和南部前陆盆地共有的前陆隆起 ,显示为对称型复合前陆盆地 ;该盆地形成于晚三叠世 ,并持续发育至早白垩世 ,盆地中充填了巨厚的同构造期的复理石和磨拉石 ,具有总体向上变粗变浅的充填序列 ,以不整合面可将其划分为 5个由顶底不整合面限制的构造层序 ,其中晚三叠世诺利期构造层序对应于金沙江缝合带主碰撞期 ,晚三叠世瑞替期构造层序对应于金沙江缝合带碰撞闭合后冲断抬升 ,早侏罗世构造层序对应于班公湖—怒江缝合带初始逆冲推覆 ,中侏罗世—早白垩世构造层序对应于班公湖—怒江缝合带主碰撞期 ,中白垩世构造层序为班公湖—怒江缝合带碰撞闭合后冲断抬升与金沙江缝合带冲断抬升的产物 ,为中生代羌塘盆地关闭后的磨拉石建造     

川西类前陆盆地晚三叠世须家河期构造演化及层序充填样式

晚三叠世须家河期.龙门山构造活动呈现明显的阶段性。须二段和须四段沉积期为龙门山逆冲推覆活动期,川西类前陆盆地沉积、沉降中心位于靠近盆缘冲断带一侧的前渊坳陷内,盆地两侧以储层发育和沉积极不对称为特征。在盆缘冲断带一侧,随着龙门山造山带构造活动的增强,下切剥蚀力也不断增强,低位体系域相对发育.而高位体系域则因后期暴露剥蚀而保存不完整;在前陆隆起斜坡带一侧,表现为稳定的缓慢隆升,下切侵蚀作用较弱。故低位体系域缺失或不发育,而高位体系域则因后期剥蚀较弱而相对发育。须三段和须五段沉积期为龙门山逆冲推覆休眠期.川西类前陆盆地的沉积、沉降中心向前陆隆起方向迁移,盆地两侧沉积的不对称性也逐渐减弱.以发育区域性盖层和生油层为特征。其层序充填样式与活动期相似。但造山带前缘因构造剥蚀相对减弱而使沉积层序.尤其是高位体系域保存相对完整。而前陆隆起区则主要因沉积物供应不足而使层序发育相对不完整.只保留最大洪泛面附近的沉积。     

川西前陆盆地侏罗纪构造层序地层格架内沉积充填特征

为了研究侏罗纪龙门山造山带与川西前陆盆地盆山关系,以侏罗系3个构造层序(TS1~TS3)体系域(BE, BW)为研究的基本单元,通过对川西前陆盆地构造层序充填特征的研究发现:龙门山造山带构造运动与沉积盆地的构造层序充填特征吻合较好,并且龙门山造山带北段,中段,南段在各期次构造活动中活动情况具有差异。TS1BE期,川西前陆盆地北部和南部地区都发育有冲积扇-扇三角洲沉积,中部地区为三角洲沉积,显示该期龙门山造山带北段和南段构造活动可能较为剧烈,中段相对较平缓。TS1BW期,川西前陆盆地北部和南部地区都以湖泊沉积为特征,仅在川西前陆盆地中部地区发育有三角洲沉积,显示本期龙门山造山带构造活动不发育,较为平稳。TS2BE期,川西前陆盆地北部和南部地区自西而东为冲积扇,三角洲—滨湖、浅湖沉积环境,中部地区为三角洲沉积,显示龙门山造山带又一次剧烈隆升,且北段和南段活动较为剧烈,中段相对较弱。TS2BW期,层序充填结构表明龙门山造山带北段和中段活动情况再次趋缓,但南段构造活动仍然较为活跃。TS3BE期,川西前陆盆地北部和南部地区发育有冲积扇沉积,中部则以三角洲-湖泊沉积为特征,显示该期龙门山造山带北段和南段都发生了较为剧烈的构造隆升运动,龙门山造山带中段,构造活动相对较为平缓。TS3BW期,龙门山造山带北段和中段构造活动减弱,南段活动持续加剧,于芦山两河口地区沉积有巨厚的冲积扇沉积物。     

盆山耦合与前陆盆地成藏区带分析

经济全球化导致油气勘探全球化,板块学说在理论上提供全球油气勘探基础,亚洲大陆与北美大陆盆山体系在实践上提供全球油气勘探经验。盆山耦合体系存在3类造山带与3类前陆盆地即:(1)俯冲造山带与弧后前陆盆地;(2)碰撞造山带与周缘前陆盆地;(3)陆内造山带与陆内前陆盆地。前陆盆地成藏区带勘探中,在空间上应将造山带前麓褶皱—冲断带层与前陆盆地作为统一应变场,在时间上应将前冲断作用沉积层序,同冲断作用沉积层序和后冲断作用沉积层序作为整体来进行勘探。     

库车前陆盆地古近系露头层序地层学

应用露头层序地层学基本原理和方法,在新疆库车前陆盆地古近系各种层序界面露头标志分析的基础上,探讨了该区三级层序、层序区域对比的基本特征以及层序发育的盆缘背景.研究表明:古近纪库车前陆盆地充填整体为一个二级层序,并进一步划分为8个三级层序;盆地基底的东、西分块是造成古近系充填层序纵向发育不协调的深部原因;通过沉积体系类型及演化与盆缘背景、构造活动的响应关系分析,推论了库车前陆盆地楔顶带的存在;楔顶带的发育抑制了构造活动期源于造山带的物源供给,使前陆盆地前渊带的沉积物供给速率趋于稳定.     

试论龙门山逆冲推覆作用的沉积响应─—以成都盆地为例

本文根据现今龙门山前陆盆地（成都盆地）沉积特征和龙门山冲断带第四纪以来的逆冲推覆事件，研究了龙门山逆冲推覆作用对成都盆地沉积的控制作用和成都盆地沉积对龙门山逆冲推覆作用的响应，总结了龙门山冲断带逆冲推覆作用的沉积响应模式和地层标识，为研究龙门山冲断带地质演化提供了新的思路和方法。     

Tectonic Evolution of the Middle Frontal Area of the Longmen Mountain Thrust Belt, Western Sichuan Basin, China

By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt,China,we concluded that it had experienced five tectonic stages:(1)the formation stage (T3x) of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain;(2)the stable tectonic stage(J1)where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin;(3)the intense tectonic stage(J2-3),namely the early Yanshan movement;(4) continuous tectonic movement(K-E),namely the late Yaushan movement and early Himalayan movement;and(5)the formation of Longrnen Mountain(N-Q),namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain'S formation.The Himalayan movement affected Longmen Mountain the most;the strata thrust intensively and were eroded severely.There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.     

Tectonic Evolution of the Middle Frontal Area of the Longmen Mountain Thrust Belt,Western Sichuan Basin,China

By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt, China, we concluded that it had experienced five tectonic stages: (1) the formation stage (T3x) of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain; (2) the stable tectonic stage (J1) where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin; (3) the intense tectonic stage (J2-3), namely the early Yanshan movement; (4) continuous tectonic movement (K–E), namely the late Yanshan movement and early Himalayan movement; and (5) the formation of Longmen Mountain (N–Q), namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain’s formation. The Himalayan movement affected Longmen Mountain the most; the strata thrust intensively and were eroded severely. There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.     

米仓山构造转换带特征及转换模式

米仓山构造带被北东走向的龙门山陆内复合造山带及北北西走向的大巴山前陆冲断带夹持于其间,两个构造带平面上组成一个“八”字形构造,空间上为一个向北收敛,向南发散背倾型的Ⅰ型三角带构造.在两大构造带前展式扩展变形晚期的过程中,米仓山则起到调节这两大构造带构造平衡的作用,因此为一构造转换带.米仓山构造转换带由北向南可以分为基底...     

The Deep Geophysical Structure of the Middle Section of the Longmen Mountains Tectonic Belt and its Relation to the Wenchuan Earthquake

Investigation of the deep geophysical structure of the Longmen Mountains tectonic belt and its relation to the Wenchuan Earthquake is important for the study of earthquakes. By using magnetotelluric sounding profiles of the Luqu–Zhongjiang and Anxian–Suining; seismic sounding profiles of the Sichuan Maowen–Chongqing Gongtan, the Qinghai Huashi Gorge–Sichuan Jianyang, and the Batang–Zizhong; and magnetogravimetric data of the Longmen Mountains region, the deep geophysical structure of the Songpan–Ganzi block, the western Sichuan foreland basin, and the Longmen Mountains tectonic belt and their relation was discussed. The eastward extrusion of the Qinghai–Tibet Plateau thrusts the Songpan–Ganzi block upon the Yangtze block, which obstructs the eastward movement of the Qinghai–Tibet Plateau. The Maoxian–Wenchuan, Beichuan–Yingxiu, and Anxian–Guanxian faults of the Longmen Mountains fault belt dip to northwest with different dip angles and gradually converge in the deeper parts. Geophysical structure suggests that an intracrustal low-velocity, low-resistivity, and high-conductivity layer is common between the middle and upper crust west of the Longmen Mountains tectonic belt but not in the upper Yangtze block. The Sichuan Basin has a thick low-resistance sedimentary layer on a stable high-resistance basement; moreover, there are secondary paleohighs and depression structures at the lower part of the western Sichuan foreland basin with characteristic of high magnetic anomalies, whereas the Songpan–Ganzi block has a high resisitivity cover of upper crust and continues to a low-resistance layer. Considering the Longmen Mountains tectonic belt as the boundary, there are Bouguer gravity anomalies of "one belt between two zones." Thus, we infer that there is a corresponding relation between the inferred crystalline basement of the Songpan block and the underlying basin basement of the Longmen Mountains fault belt. Furthermore, there may be an extensive ancient Yangtze block, which is west of the Ruoergai block. In addition, the crust–mantle ductile shear zone under the Longmen Mountains tectonic belt is the main fault, whereas the Beichuan–Yingxiu and Anxian–Guanxian faults at the surface are earthquake faults. The Wenchuan Ms 8.0 earthquake might be attributed to the collision of the Yangtze block and the Qinghai–Tibet Plateau. The eastward obduction of the eastern edge of the Qinghai–Tibet Plateau and eastward subduction of its deeper part under the influence of the collision of the Indian, Pacific, and Philippine Plates with the Eurasia Plate might have caused the Longmen Mountains tectonic belt to cut the Moho and extend to the middle and upper crust; thus, creating high stress concentration and rapid energy release zone.     

川西前陆盆地中—新生代沉积迁移与构造转换

川西前陆盆地中—新生代各构造层的残余厚度展布和沉积特征分析发现,四川克拉通周缘的前陆盆地在晚三叠世时期发育于龙门山山前,明显属于龙门山褶皱逆冲构造载荷所形成的前渊凹陷;侏罗纪早期的沉积地层呈面状分布,没有表现出显著的挠曲沉降,指示了一个构造相对平静的阶段;中侏罗世早期前渊凹陷迁移至龙门山北段和米仓山山前,前渊沉积从晚三叠世的北东向转换为近东西向,广泛的湖泊相沉积预示了前陆盆地的欠充填状态;中侏罗世中晚期,川西盆地沉降中心又迁移到大巴山山前,相应的挠曲变形又从近东西向转化为北西向,构成了大巴山的前渊凹陷;晚侏罗世—早白垩世时期,沉降中心再次回到米仓山山前,巨厚的前渊凹陷沉积指示了米仓山冲断带的主要活动时期;白垩纪末—古近纪的前渊凹陷则跃迁至雅安—名山地区。川西前陆盆地的同造山沉降中心以四川盆地中心为核心在西部和北部呈弧形迁移,沉积序列不断更替和叠加。中生界各构造层底界构造图显示现今的构造低部位位于川西北地区和川西南地区,在川西北地区均有东西走向的等值线分布,而川西南地区等值线走向则为北东-南西向。因此分析认为,晚侏罗世至早白垩世的构造变形可能控制了川西盆地现今的地层变形,形成了川西北地区的南北向构造挤压结构,而晚期的新生代构造变形则主要体现在川西盆地的西南部,形成北东-南西向的地层展布特征。     

DEFORMATIONAL AND METAMORPHIC HISTORY OF THE CENTRAL LONGMEN MOUNTAINS, SICHUAN CHINA

DEFORMATIONAL AND METAMORPHIC HISTORY OF THE CENTRAL LONGMEN MOUNTAINS, SICHUAN CHINA1　ArneDC ,WorleyBA ,WilsonCJL ,etal.Differentialexhumationinresponsetoepisodicthrustingalongtheeasternmar ginoftheTibetanPlateau[J] .Tectonophysics,1997,2 80 :2 39～ 2 56 . 2　ChenSF ,WilsonCJL ,WorleyBA .TectonictransitionfromtheSongpan GarzeFoldBelttotheSichuanBasin,south westernChina[J] .BasinResearch ,1995,7:2 35～ 2 53. 3　ChenSF ,WilsonCJL .Emplaceme…     

四川盆地米仓山前陆冲断带成藏条件分析

本文运用层序地层学、平衡剖面分析与缩短量计算和生烃史恢复等方法,从区域构造分析和地震剖面解释入手,通过野外地质调查、地震资料解释、典型剖面平衡剖面分析和缩短量计算,结合成藏条件的分析和生烃史恢复,探讨了米仓山前陆冲断带构造演化特征,揭示该带的成藏条件和天然气富集特征。提出了米仓山演化模式,认为米仓山前陆冲断带成藏条件优越,可供钻探的圈闭发育,天然气勘探潜力巨大,储层、保存条件是成藏关键。其中,二叠系为主要烃源岩,二叠系生屑灰岩和飞仙关组鲕粒灰岩为主要储集层,雷口坡组和嘉陵江组膏盐岩层为主要盖层。并且,冲断带构造演化的时序性表现为由西向东变形强度、缩短量变小,变形时间变晚,同时前陆盆地的不同构造单元间的相互关系发生变化,造成勘探目的层系、圈闭幅度、类型的相应变化。     

新疆西准噶尔额敏前陆盆地的构造特征及其演化

西准噶尔吾尔喀什尔山与额敏盆地间的"盆"–"山"耦合关系清楚,盆地边界平行于造山带呈狭长带状展布。"山"区为志留系–石炭系海相陆源碎屑岩-火山岩沉积组合,"盆"区为二叠系陆相磨拉石与新近系红色砂砾岩及第四系河流阶地堆积,具有典型的海相-陆相双层结构。盆缘被巴尔雷克前陆冲断带围限,"山"区发育铲式逆冲断层与蛇头构造、叠瓦扇构造等逆冲推覆构造。表明该"盆"–"山"组合为一典型的前陆盆地系统。额敏前陆盆地形成于早二叠世,属后期冲断变形影响较弱、早期前陆盆地结构特征较明显的"早衰型"前陆盆地。这一成果为额敏盆地乃至西准噶尔盆地分析、构造演化、沉积作用、"盆"–"山"耦合等研究提供了重要信息。     

中－新生代龙门山的差异隆升

通过对采自龙门山南段、中段和北段花岗岩与砂岩样品中的磷灰石、锆石的裂变径迹年龄的分析,发现中生代以来龙门山的隆升在走向上存在分段性,在近东西方向上存在分带性。从松潘－甘孜褶皱带→龙门山冲断带→川西前陆盆地：松潘－甘孜褶皱带整体发生区域隆升,裂变径迹年龄与高程呈正相关关系;在龙门山冲断带,裂变径迹年龄与高程呈负相关关系或无关,说明冲断层在隆升过程中起主导作用;在川西前陆盆地,样品随埋深发生部分或全部退火。茂县－汶川断裂两侧锆石裂变径迹年龄差异明显而磷灰石裂变径迹年龄无明显差异,显示茂县－汶川断裂以西地区在38～10 Ma发生过更为快速的隆升;北川断裂两侧磷灰石裂变径迹年龄差异明显,表明北川断裂以西地区在10～0 Ma发生过快速隆升。从走向上看,从龙门山北段向南段,锆石裂变径迹年龄呈逐渐增大的趋势,这可能意味着印支末期或燕山早期,龙门山北段发生了更快的隆升;而磷灰石裂变径迹年龄总体上从龙门山北段向中段和南段呈递减趋势,反映新生代期间龙门山中、南段隆升更快。     

Meso-Cenozoic Tectonic Events Recorded by Apatite Fission Track in the Northern Longmen-Micang Mountains Region

There is a cross-cutting relationship between the E-W trending structures and the NE-trending structures in the northern Longmen-Micang Mountains region,which reflects possible regional tectonic transi...