青藏高原的构造分区及其边界的变形构造特征

宏观构造特征的确立对青藏高原隆升和“动力学建模”具有重要意义。青藏高原是由来自塔里木-中朝板块的北昆仑-阿尔金-祁连地体,华南-东南亚板块的南昆仑地体、可可西里-巴颜喀拉地体和冈瓦纳古陆的羌塘地体、冈底斯地体及喜马拉雅地体等3大板块(或古陆)的6个地体经多次裂解、会聚和陆内俯冲作用拼合而成的巨型“会聚-陆内俯冲型”岩石圈块体,它以青藏高原南缘结合带、青藏高原北缘结合带和青藏高原东缘结合带依次与印度岩石圈块体、塔里木-阿拉善-鄂尔多斯岩石圈块体和扬子岩石圈块体相隔。按现今动力学特征,这一巨型岩石圈块体(一级构造单元)又可进一步划分为喜马拉雅、藏北、青南和昆仑-阿尔金-祁连等4个二级构造单元(地块),它们依次以雅鲁藏布江结合带、西金乌拉-金沙江结合带、中昆仑结合带为界。4个地块又可进一步划分为若干以断裂为界的三级构造单元(地体)。组成青藏岩石圈块体的各构造单元处于统一的地球动力学系统,它总的表现为:在印度板块向欧亚板块持续、强烈俯冲和热的、具柔性流变学特征的青藏块体整体向北北东方向移动的区域构造背景上,其南、北两侧的喜马拉雅地块、昆仑-阿尔金-祁连地块分别向冷的、刚性的印度岩石圈块体和塔里木- 阿拉善-鄂尔多斯岩石圈块体不对称逆冲叠覆。位于青藏高原腹部的藏北地块和青南地块,在深部存在大量低速体向上涌动和整体自西向东扩展的区域构造背景上,前者叠置近南北向挤压,形成以南北向断陷带及北西和北东向共轭走滑为主的构造格局,而青南地块除松潘-甘孜地体显示自北而南的逆冲叠覆外,可可西里-巴颜喀拉地体以逐一向东挤出的左行走滑作用为主,以致整个青南地块呈现向扬子岩石圈块体逆冲扩展和向三江构造带平移扩展。因此,就现今动力学而言,青藏高原在随着时间推移、隆升速度不断加快的同时,还逐渐向外缘的刚性地块扩展,即高原面积在不断增大。因此青藏高原的边界具有扩展性质,按扩展机制可区分两类扩展型动力边界:走滑型扩展边界和逆冲型扩展边界。典型的走滑型扩展边界位于青藏高原北缘的阿尔金山和青藏高原东缘的三江地区,青藏高原南缘的动力边界属典型的逆冲型扩展边界,而位于祁连山和龙门山的动力边界兼有逆冲和走滑双重扩展性质。     

南黄海中-新生代裂谷盆地构造-热演化:对成盆机制和烃源岩热演化的指示

基于Advanced McKenzie地球动力学模型和Easy%R_oDL化学动力学模型,建立了南黄海中-新生代（K₁3-Q）裂谷盆地的构造-热演化史,结合盆地深部壳幔结构、梳理周缘中-新生代板块汇聚与离散过程,讨论了该盆地低地热状态成因、成盆机制和烃源岩热演化.盆地地壳伸展系数约为1.22,岩石圈地幔伸展系数约为1.06;由裂陷期（K₁3-E₂）至今,最高热流值仅由约76 mW/m2降低至约66 mW/m2,最高地温梯度仅由约37 ℃/km降低至约30 ℃/km,首次揭示低地热状态贯穿整个裂谷盆地发育阶段.低岩石圈地幔伸展系数、深部非镜像莫霍面分布、盆地发育阶段仅处于弧后远场拉张应力环境,均指示成盆过程中深部伸展上涌强度低,是导致其持续低地热状态的根本原因,深部热应力不是其主要成盆动力来源;依据高地壳伸展系数和控盆拆离断层演化,认为印支-燕山期先存逆冲断裂复活形成壳间拆离体系,并以简单剪切变形方式控制裂谷盆地发育,是其根本成盆机制;南、北部坳陷烃源岩主排烃期为三垛组二段沉积时期,自渐新世构造反转后热演化终止,古埋深和古地温场条件共同控制现今南、北部坳陷相同深度烃源岩热成熟度差异.      

柴达木盆地构造体系特征及其成盆动力学意义

本文从李四光教授构造体系理论出发综合应用盆地构造解析、平衡地质剖面恢复等方法,探讨了柴达木盆地构造体系特征及其形成的地球动力学背景和地球动力学模型.柴达木盆地受到印度板块、西伯利亚板块、太平洋板块三大板块的共同影响,围绕中部刚性基底周边发育北部祁连山、南部东昆仑山及西部阿尔金山三大构造体系,每个构造体系都是由主要断裂及...     

北黄海盆地构造变形及动力学演化过程

以北黄海盆地构造几何学、运动学特征为基础,探讨了北黄海盆地的构造变形样式及动力学演化过程。研究表明,北黄海盆地的构造变形包括伸展构造变形、挤压构造变形、扭动构造变形以及反转构造变形等,北黄海盆地发育的区域动力学背景即是以区域拉伸作用为主、且叠加有水平挤压作用以及相关的扭动作用,并由此导致了北黄海盆地是以一系列地堑、半地堑式坳陷组成的拉张断陷盆地;北黄海盆地的伸展、挤压与升降作用受控于板块相互作用引起的区域引张与挤压应力场并辅以深部软流圈的微弱上拱隆起作用,其动力学演化过程包括晚侏罗世—早白垩世伸展断陷、晚白垩世—古新世热隆、始新世—渐新世裂陷、渐新世末期—新近纪早期构造反转以及新近纪热沉降等5个阶段。     

六盘山地区早白垩世磁性地层年代及其构造意义

研究六盘山白垩纪盆地演化对于认识中国大陆白垩纪及现今构造-环境格局形成具有重要意义。通过对六盘山地区火石寨剖面的沉积地层进行古地磁采样测量,初步获得六盘山群的磁性地层年代为100～130 Ma。综合古地磁测年结果、盆地沉积演化和构造事件分析,认为白垩纪六盘山盆地具拉张断陷性质,经历了早期拉张裂陷阶段(125.3 ～ 129.6 Ma)、中期扩张-稳定坳陷阶段(109.6 ～125.3 Ma)和晚期湖盆萎缩阶段(102.0～ 109.6 Ma)。盆地早期拉张裂陷和中期扩张坳陷阶段的时限与目前已确认的中国东部构造伸展转折的高峰期(110 ~ 140 Ma)相对应,是对中国东部岩石圈减薄作用和构造体制转变的响应。     

The Earlier Spreading of South China Sea Basin due to the Late Mesozoic to Early Cenozoic Extension of South China Block： Structural Styles and Chronological Evidence from the Dulong-Song Chay Metamorphic Dome, Southwest China

INTRODUCTION Whatmechanismresultedinthespreadingof SouthChinaSeabasin(SCSB)?Wasitreallypro ducedbytheinteractionofperipheralplatesofthe SCSBorAilaoshan RedRiversinistralfault(Fig.1)? Figure1.AnoutlinetectonicmapofSouthChinablockandIndochinablock(modified…     

塔里木地块北部横向构造及断条模式

提要:塔里木盆地北部与西南天山毗邻区域发育的浅部构造系统是喀什坳陷—柯坪塔格逆冲推覆构造带—库车前陆坳陷冲断带,它们在山前以1～3排方式平行造山带展布,是一套由底板滑脱断坪和断坡构成的逆冲推覆系统,具有明显的横向分段性;该区深部构造系统却是一组以北西向为主展布的断条构造,并可以划分出4个一级断条构造。笔者从构造层变形、重力、航磁异常场及天然地震平面分布密度等几个角度,对区内深部横向构造系统进行了研究,并利用天然地震深度/频次统计结果,识别出圈层拆离解耦面的深度分布,进而探讨了深部横向构造运动的岩石圈地壳圈层归属,对区域北西向横向构造系统做了详细的论述。本文选择喀拉玉尔滚断裂带和库尔勒断裂带进行重点解剖,研究了横向构造与浅部构造的转换关系,最终提出了塔里木地块北部断条构造几何学运动学模式,即塔里木地块深部向北西方向运动受到古西南天山的阻挡性约束而“被迫”俯冲,岩石圈地壳发生拆离解耦,原有的横向构造——北西向构造带(断裂带)被激活,使得俯冲系统以断条为单位进行俯冲;在俯冲过程中,岩石圈地壳的拆离及横向构造被激活的方向是从约束体(南天山)附近开始,向塔里木盆地(北部)的腹地方向推进,因此,越是接近造山带区域,断条俯冲状态的差异越明显,横向分段性越突出;而正因为塔里木地块以断条形式向南天山的俯冲行为,使得山前坳陷冲断带(及天山)发生分段。     

Evolution of the lithospheric mantle during passive rifting: Inferences from the Alpine–Apennine orogenic peridotites

This paper presents an updated review of recent field/structural and petrologic/geochemical studies on orogenic peridotites from the Alpine–Apennine ophiolites (NW Italy). Results provide determinant constraints to the evolution of the lithospheric mantle during passive rifting of the fossil Ligurian Tethys oceanic basin.The pre-rift, spinel lherzolites precursors, preserved in the mantle section of the Ligurian ophiolites, were resident in the lithosphere along an intermediate geothermal gradient (T about 1000 °C, P compatible with spinel-peridotite facies). Passive rifting by far-field tectonic forces induced whole-lithosphere extension and thinning (the a-magmatic stage). After significant thinning of the lithosphere, the passively upwelling asthenosphere underwent decompression melting along the axial zone of extension. Silica-undersaturated melt fractions infiltrated via diffuse/focused porous-flow through the lithospheric mantle under extension (the magmatic stage) and underwent pyroxenes-dissolving/olivine-crystallizing interaction with the percolated host peridotite.Pyroxenes assimilation and olivine deposition modified the melt compositions into silica-saturated. These derivative liquids migrated to shallower, plagioclase-peridotite facies levels, where they stagnated and impregnated/refertilized the lithospheric mantle. Melt thermal advection by melt infiltration heated to temperatures higher than 1200 °C the lithospheric mantle column above the melting asthenosphere.The syn-rift magmatic and tectonic processes induced significant rheological softening/weakening that destabilized the lithospheric mantle of the Europe–Adria plate along the axial zone of extension. The presence of destabilized lithospheric mantle between the future continental margins played a determinant role in promoting the geodynamic evolution from pre-oceanic rifting to oceanic spreading.The active upwelling of hotter/deeper asthenosphere inside the destabilized axial zone promoted transition to active rifting, enhancing continent break-up. Asthenosphere underwent partial melting and formed aggregated MORB liquids that migrated inside high-porosity dunite channels. The MORB liquids formed olivine-gabbro intrusions and pillowed lava flows (the oceanic crustal rocks).This paper evidences the primary role of mantle destabilization by melt infiltration in the geodynamic evolution of the Ligurian Tethys rifting.     

大别山北麓斑岩型钼矿床地质特征、成矿时代及其成矿构造背景

在野外调查和测试分析的基础上,结合前人的研究成果,综合论述了大别山北麓斑岩型钼矿床的地质特征、形成时代和构造背景。大别山北麓斑岩型钼矿床总体沿区域构造线呈北西向狭长带状展布,具有近东西向成带、南北向成群的空间展布特征,其形成与燕山期中酸性浅成-超浅成小型花岗斑岩体有关,钼矿床直接产于岩体内外接触带及其附近的围岩中,矿床类型主要为斑岩型、斑岩-矽卡岩型及少量热液石英脉型。结合Re-Os同位素年龄数据,探讨了大别山北麓斑岩型钼矿床的成矿物质来源、成矿流体、成矿时代、主要成矿作用的时限以及成矿地球动力学背景。结果表明:大别山北麓地区钼矿床的主要成矿作用时限为142~137 Ma和127~110 Ma,对应的地球动力学背景为中国东部地球动力学体制大转换晚期的岩石圈拆沉及伸展减薄的构造背景。     

中国中、新生代含油气盆地成因类型、构造体系及地球动力学模式

讨论了中国中、新生代含油气盆地的成因类型、构造体系和地球动力学模式：（１）按照地球动力学背景，将中国中、新生代盆地划分成伸展、缩短挠曲和走滑３种成因类型；（２）提出了含油气盆地构造体系的概念，并按照盆地成因类型、板块构造背景和构造演化讨论了中、新生代含油气盆地构造体系的分布；（３）根据构造几何学、运动学和动力学、火山岩岩石地球化学、基底和岩石圈结构以及地温场等特征，建立了有关大陆内伸展盆地和前陆盆地的地球动力学模式。     

东天山北部古生代重大构造事件及其对中亚造山带演化的启示：基于1∶5万板房沟幅和小柳沟幅地质调查新证据

本文基于新疆哈密地区1∶5万板房沟幅和小柳沟幅区域地质调查新成果,对东天山北部古生代的重大构造事件以及演化历史进行了系统的梳理。基于下志留统与奥陶系之间角度不整合、下石炭统与泥盆系之间平行不整合以及上石炭统二道沟组与下伏岩系之间的角度不整合的确定,揭示奥陶纪与志留纪之交、泥盆纪与石炭纪之交以及晚石炭世期间存在几次重大构造事件。结合古生代不同时期沉积大地构造背景转换、岩浆活动构造环境转换以及构造变形格式转换的地质新纪录,提出奥陶纪与志留纪之交的造山事件为北部阿尔曼太洋闭合导致准噶尔—吐哈地块与阿尔泰地块碰撞的响应;泥盆纪与早石炭世之间的造陆构造事件可能是北部卡拉麦里洋盆初始汇拢碰撞的响应,其平行不整合以及下伏的志留纪—泥盆纪较稳定环境的沉积序列预示着介于卡拉麦里洋盆与南部北天山洋盆之间的准噶尔—吐哈地块为古亚洲洋盆体系中相对刚性的稳定陆块区,研究区作为准噶尔—吐哈地块的北部被动陆缘受卡拉麦里洋盆汇聚的影响较小;晚石炭世的造山事件则表现为响应卡拉麦里洋盆闭合后周缘前陆盆地的演化,是早石炭世沿卡拉麦里缝合带发生陆块碰撞以来挤压构造作用峰期的产物,其奠定了东天山北部北西-南东向构造基本格局。本文还重新界定莫钦乌拉断裂为北天山构造带(准噶尔—吐哈地块)与东准噶尔构造带的构造-地层分区界线,推断其为卡拉麦里缝合带向南东的延伸,并讨论了早石炭世受控不同构造体制的沉积和岩浆纪录的空间差异性,认为早石炭世北部莫钦乌拉山区域为与北侧卡拉麦里洋盆闭合后周缘挤压前陆盆地的发育过程,而南部博格达—哈尔里克山则总体呈现为响应南侧北天山洋盆闭合后的碰撞后伸展裂谷发育过程。     

南北构造带北段S波分裂研究及其动力学意义

南北构造带北段位于青藏高原东北缘及其向北东方向扩展的区域,其岩石圈变形特征对于探讨青藏高原东北缘变形机制及其扩展范围具有非常关键的意义。地震波各向异性能很好地反映上地幔的变形特征。因此,本文对布设在南北构造带北段的流动地震台站记录的远震波形资料进行S波分裂研究,获得了研究区上地幔各向异性图像以及该区岩石圈地幔的变形特征信息。S波分裂研究结果表明,研究区地震波各向异性来自于上地幔,区内不同构造单元上地幔各向异性方向不尽相同。快波方向分布显示,青藏高原东北缘,鄂尔多斯西缘以及贺兰构造带北段的快波方向主要表现为NW-SE向,与前人在银川地堑和贺兰构造带中、北部得到的NW-SE向的上地幔各向异性方向一致,显示这些地区岩石圈地幔变形一致,该结果表明青藏高原东北缘向北东方向扩展的影响范围已到达贺兰构造带北段。阿拉善地块内部快波方向显示为NE-SW向,与阿拉善地块北部存在的北东向展布的晚古生代岩浆岩方向一致,表明该NE-SW向的快波方向可能代表地是“化石”各向异性,是晚古生代阿拉善地块受到古亚洲洋闭合作用的结果。此外,鄂尔多斯地块内也存在NE-SW向的各向异性方向,与区内中-晚侏罗世存在的NE-SW向逆冲推覆构造方向一致,因此该各向异性方向也代表了“化石”各向异性,是鄂尔多斯地块受到古特提斯构造域的块体碰撞、古太平洋板块北西向俯冲以及西伯利亚板块向南俯冲共同作用的结果。     

南黄海盆地南部坳陷晚白垩世-第四纪构造演化对油气的控制

受盆地差异成因机制的影响,南黄海盆地南部坳陷类型及构造演化有多种认识,并存在很大争议。通过重新划分构造单元和构造层,深入研究构造特征;将建湖隆起延伸入海,首次提出将南二凹陷划分为南二凹陷北和南二凹陷南两个凹陷;建立盆地构造格架,明确中新生代构造演化阶段及性质,以张引作用为主与挤压隆升相间,构成多期构造旋回;揭示构造对油气的控制作用,确定阜宁组为烃源岩发育有利层位,南五凹陷为烃源岩分布最优区域,并认为南五凹陷可以存在二次生烃;进行油气成藏模式对比,从而优选南五凹陷为最优区块。     

盆地形成与演化的动力学类型及其地球动力学机制

借鉴国内外已有的盆地研究成果,在盆地分析的基础上,从岩石圈板块作用、岩石圈深部作用和岩石圈表生作用3个方面,兼顾系统性、科学性和应用性,确立了盆地新的分类原则,由此深入研究了盆地形成与演化的动力学类型,并进一步阐述了盆地形成与演化的地球动力学机制。研究结果表明:在盆地分类中,首先主要根据盆地形成的地球动力学环境如岩石圈板块作用环境、深部作用环境以及表生作用环境来划分大类;再根据盆地形成与演化的各种地质作用及其动力学过程如构造作用(伸展、挤压或剪切过程)、热力作用及重力作用进行主要类型划分;再根据盆地的基底性质和地壳类型(如陆壳、洋壳或过渡壳)以及盆地的沉积充填史和构造古地理等(如海相盆地、陆相盆地或过渡相盆地)细分亚类。盆地形成与演化的动力学类型主要包括:单一构造或热体制下盆地演化时的原型盆地类型、单一重力体制下盆地演化的原型盆地类型、多种构造-热体制下盆地演化的叠合盆地类型以及多种构造-热体制下盆地演化的残留盆地类型。在单一构造或热体制下,从板块作用或壳幔作用角度原型盆地动力学类型主要划分为:伸展盆地(陆内伸展盆地、陆间伸展盆地、大洋伸展盆地和弧后伸展盆地),挠曲盆地(弧后挠曲盆地、周缘挠曲盆地、陆内挠曲盆地),走滑盆地(走滑伸展盆地、走滑挠曲盆地)以及克拉通盆地(克拉通退缩盆地、克拉通扩展盆地和克拉通迁移盆地);单一重力体制下原型盆地动力学类型有负载盆地和撞击盆地;多种构造-热体制下的叠合盆地动力学类型有叠加盆地和复合盆地;多种构造-热体制下盆地演化的残留盆地动力学类型有伸展隆起下局部沉降引起的残留盆地、推覆褶皱隆起引起的残留盆地、俯冲至局部碰撞引起的残留盆地及周边抬升隆起引起的残留盆地。关于盆地形成与演化的地球动力学机制包括:岩石圈的板块作用机制,岩石圈的深部作用机制以及岩石圈的表生作用机制。岩石圈的板块作用机制包括板块伸展、挤压和剪切作用;岩石圈的深部作用机制包括软流圈与超级地幔柱对岩石圈的作用,尤其是壳幔作用;岩石圈的表生作用机制也很重要,包括盆地的重力作用、大气作用、海洋作用和生物作用。通过本文的研究,可以为研究整个岩石圈演化、壳幔作用、地球动力学过程以及成藏成矿机制奠定重要理论基础;同时,对于沉积盆地矿产资源、能源资源、水资源勘探和开发,以及灾害防治和环境保护也具有重要应用价值。     

下扬子区新生代伸展构造变形及其区域构造意义

下扬子区是中国东部重要的含油气盆地区之一,其新生代伸展构造变形一直是下扬子新生代构造动力学的核心问题.通过对下扬子海陆全区新生代断陷盆地结构与构造格局分析,明确了下扬子区伸展构造变形特征,探讨了变形成因机制及其区域构造意义.区域构造分析表明,下扬子区伸展变形构造由一系列NNE-NE-NEE走向的总体呈弧形展布的正断层构成,表现为受伸展断裂系统控制的断陷结构,具有多向伸展特征,自南向北可分为江南、沿江-苏北-南黄海和南黄海北部3个构造伸展区.有限元数值与构造物理模拟表明,受控于太平洋板块俯冲推挤传递至陆内的侧向构造作用力,下扬子块体南向蠕移,区域上近南北向伸展变形,郯庐断裂右旋走滑,两者共同构成一个"右旋侧向扩展变形"系统.在区域构造上,大兴安岭-太行山-武陵山重力梯度带以东的中国东部新生代伸展变形构造和盆地成因与古太平洋板缘边界条件密切相关.      

Assemblage of strike-slip faults and tectonic extension and compression analysis: A case study of a Lower Permian commercial coal reservoir in China

The Qinshui Basin was an active residual basin in the Mesozoic and Cenozoic periods and is located inside the North China Plate. The Upper Paleozoic strata in the basin have been strongly deformed and have developed a large number of strike-slip faults. The Qinshui Basin has been influenced by compressive stress from the northeast direction since the Himalayan period, and the faults have a dextral strike-slip property. Under the action of such a stress field, the right-slip, right-order faults indicate an extension region, and the right-slip, left-order faults indicate a compression region. Based on this principle, the extension and the compression areas were divided. From northwest to southeast direction in the study area, two types of regions have interactive distribution characteristics. For the Fanzhuang block in the eastern part of the study area, the fault distribution has an ‘S-type’ trend from north to south, and the middle extension region is the ‘elbow’ or the ‘hinge zone’ of the ‘S-type’ area, which can also be called the ‘stress transition zone’. The tectonic stress field of the stress transition zone is complex, and tensile fractures are usually extremely developed with extension tectonics. Gas wells with higher capacity are mainly distributed in the extension zone, while the capacity of the gas wells in the compression area is usually lower. The study showed that the distribution of the gas well capacity is consistent with the tectonic extension and compression analysis, indicating that the tectonic analysis method in this study is reliable. The Upper Paleozoic coal measure strata in the Qinshui Basin represent a whole gas-bearing and stress-bearing system, the tectonic analysis method in this study is also applicable to other types of tight reservoirs for this set of depositional systems.     

Geochemistry and tectonic development of Cenozoic magmatism in the Carpathian–Pannonian region

This review considers the magmatic processes in the Carpathian–Pannonian Region (CPR) from Early Miocene to Recent times, as well as the contemporaneous magmatism at its southern boundary in the Dinaride and Balkans regions. This geodynamic system was controlled by the Cretaceous to Neogene subduction and collision of Africa with Eurasia, especially by Adria that generated the Alps to the north, the Dinaride–Hellenide belt to the east and caused extrusion, collision and inversion tectonics in the CPR. This long-lived subduction system supplied the mantle lithosphere with various subduction components. The CPR contains magmatic rocks of highly diverse compositions (calc-alkaline, K-alkalic, ultrapotassic and Na-alkalic), all generated in response to complex post-collisional tectonic processes. These processes formed extensional basins in response to an interplay of compression and extension within two microplates: ALCAPA and Tisza–Dacia. Competition between the different tectonic processes at both local and regional scales caused variations in the associated magmatism, mainly as a result of extension and differences in the rheological properties and composition of the lithosphere. Extension led to disintegration of the microplates that finally developed into two basin systems: the Pannonian and Transylvanian basins. The southern border of the CPR is edged by the Adria microplate via Sava and Vardar zones that acted as regional transcurrent tectonic areas during Miocene–Recent times.Major, trace element and isotopic data of post-Early Miocene magmatic rocks from the CPR suggest that subduction components were preserved in the lithospheric mantle after the Cretaceous–Miocene subduction and were reactivated especially by extensional tectonic processes that allowed uprise of the asthenosphere. Changes in the composition of the mantle through time support geodynamic scenarios of post-collision and extension processes linked to the evolution of the main blocks and their boundary relations. Weak lithospheric blocks (i.e. ALCAPA and western Tisza) generated the Pannonian basin and the adjacent Styrian, Transdanubian and Z?rand basins which show high rates of vertical movement accompanied by a range of magmatic compositions. Strong lithospheric blocks (i.e. Dacia) were only marginally deformed, where strike–slip faulting was associated with magmatism and extension. At the boundary of Adria and Tisza–Dacia strike–slip tectonics and core complex extension were associated with small volume Miocene magmatism in narrow extensional sedimentary basins or granitoids in core-complex detachment systems along older suture zones (Sava and Vardar) accommodating the extension in the Pannonian basin and afterward Pliocene–Quaternary inversion. Magmas of various compositions appear to have acted as lubricants in a range of tectonic processes.     

羌塘盆地中生代构造属性

通过对羌塘盆地南北两侧构造带地质特征、构造演化历程及盆地内部中生代地层充填特征的分析,探讨了羌塘盆地中生代构造属性及地球动力学机制。研究表明:羌塘盆地经历了早、中三叠世前陆盆地,晚三叠世早、中期被动陆缘盆地,晚三叠世晚期—侏罗纪羌北前陆盆地和羌南陆被动陆缘裂陷—坳陷盆地及早白垩世前陆盆地等地质演化历程;盆地南北边界构造带复杂而有序的地球动力学环境和构造演化,决定了羌塘盆地中生代为一复杂的多旋回叠合盆地。     

Deep-water clastic evaporites deposition in the Messinian Adriatic foredeep (northern Apennines,Italy): did the Mediterranean ever dry out?

A new genetic facies model for deep-water clastic evaporites is presented, based on work carried out on the Messinian Gessoso-solfifera Formation of the northern Apennines during the last 15 years. This model is derived from the most recent siliciclastic turbidite models and describes the downcurrent transformations of a parent flow mainly composed of gypsum clasts. The model allows clearer comprehension of processes controlling the production and deposition of clastic evaporites, representing the most common evaporite facies of the northern Apennines, and the definition of the genetic and stratigraphic relationship with primary shallow-water evaporites formed and preserved in marginal settings. Due to the severe recrystallization processes usually affecting these deposits, petrographic and geochemical analyses are needed for a more accurate interpretation of the large spectrum of recognized gravity-driven deposits ranging from debrisflow to low-density turbidites. Almost all the laminar ‘balatino’ gypsum, previously considered a deep-water primary deposit, is here reinterpreted as the fine-grained product of high to low-density gravity flows. Facies associations permit the framing of the distribution of clastic evaporites into the complex tectonically controlled depositional settings of the Apennine foredeep basin. The Messinian Salinity Crisis occurred during an intense phase of geodynamic reorganization of the Mediterranean area that also produced the fragmentation of the former Miocene Apennine foredeep basin. In this area, primary shallow-water evaporites equivalent to the Mediterranean Lower Evaporites, apparently only formed in semi-closed thrust-top basins like the Vena del Gesso Basin. The subsequent uplift and subaerial exposure of such basins ended the evaporite precipitation and promoted a widespread phase of collapse leading to the resedimentation of the evaporites into deeper basins. Vertical facies sequences of clastic evaporites can be interpreted in terms of the complex interplay between the Messinian tectonic evolution of the Apennine thrust belt and related exhumation–erosional processes. The facies model here proposed could be helpful also for better comprehension of other different depositional and geodynamic contexts; the importance of clastic evaporites deposits has been overlooked in the study of other Mediterranean areas. Based on the Apennine basins experience, it is suggested here that evaporites diffused into the deeper portions of the Mediterranean basin may consist mainly of deep-water resedimented deposits rather than shallow-water to supratidal primary evaporites indicative of a complete basin desiccation.     

Upper Pleistocene tectonics in western Sardinia (Italy): Insights from the Sinis peninsula structural high

The Corsica‐Sardinia block is a lithospheric fragment whose recent role in the geodynamics of the central‐Western Mediterranean basin is still enigmatic. The most recent regional structure in Sardinia is the Plio‐Pleistocene Campidano Basin, which is considered in a ‘post‐rift’ stage since the Middle Pleistocene. New structural and stratigraphic geological surveys along with luminescence ages provide evidence to support an ongoing tectonic activity since the Marine Isotopic Stage 7 (MIS7; ca. 220 ka) on the Sinis peninsula, the structural high that bounds the north‐western side of the Campidano Basin. In particular, this paper reveals for the first time the presence of N–S striking normal faults system offsetting late Pleistocene aeolianites (130 ± 12 ka; 82 ± 9 ka).