库车冲断带秋里塔格构造带东段构造样式与构造演化

秋里塔格构造带位于库车褶皱冲断前缘,其东段包括东秋里塔格背斜和库车塔吾背斜。野外调查和地震剖面解释表明:秋里塔格构造带东段盐下发育断层转折褶皱; 盐上东秋里塔格背斜为滑脱箱状背斜,库车塔吾背斜核部为南倾逆冲断层所破坏。演化剖面显示秋里塔格构造带东段在侏罗纪断陷期发育了正断裂,其后为平静期,直到库车晚期后逆冲断层和褶皱快速发育,背斜最终形成。膏盐岩及古构造对构造变形具有重要影响,一方面作为滑脱层,分割了盐下层与盐上层,导致二者形成不同的构造样式; 另一方面塑性流动充填于背斜核部。由于膏盐岩的厚度差异,东秋里塔格背斜盐上发育褶皱,而库车塔吾背斜核部被逆冲断层破坏,膏盐层厚度还影响了膏盐层上下构造高点的相对位置。盐下构造的发育受侏罗纪古构造控制,进而影响了盐上构造的发育。     

吉林深源地震群地质构造背景与动力分析

吉林深震群位于中国东北大陆板缘古生代地槽褶皱系内,上叠有中新生代断陷裂谷盆地。区内广泛喷溢了βN_2—βQ_4玄武岩浆,深震震中大多位于火山口、火山锥玄武岩内附近。从岩浆幔漂包体、岩浆岩化、岩浆携带的上地幔岩石组合出现顺序的综合判断,上地幔可分出Ⅷ层序以及推断的深震源Ⅸ层序列,据平剖面分析深震与玄武岩浆共生活动。日本海沟—我国深震区中深源地震震源机制解表明P轴呈连续地插入我国东北上地幔深度590km层内并持续活动,深震发生的动力来自西太平洋岩石圈板块俯冲消减运动本身的挤压应力活动。     

辽宁盖县猫岭金矿床毒砂的矿物学研究及成因意义

盖县猫岭金矿床以毒砂和磁黄铁矿为主.毒砂可划分为大颗粒毒砂、细脉状及毒砂石英脉中的毒砂和细粒浸染状毒砂三种性状.毒砂与金矿化密切相关.化学分析结果表明,矿区毒砂为“硫”毒砂,形成于中低温条件、中深部位.毒砂中δ~(34)S值同辽河群的δ~(34)S相一致,表明毒砂中的硫来源于辽河群.毒砂矿物标型特征指示矿床成因     

黔西南表层脱底褶皱及对金矿床的控制作用

在研究黔西南表层脱底褶皱地表地质特征和其形成机制的基础上,认为黔西南微细粒浸染型金矿床是成岩期后构造作用下的产物,受控于表层脱底褶皱,并提出了金矿远景区和找矿方向。     

广西芒场锡-多金属矿田叠加褶皱构造及趋势面分析研究

 本文利用传统构造地质学中小构造要素统计方法,从空间上恢复并确定了芒场锡-多金属矿田内印支早期北北西向芒场复背斜和燕山晚期北北东向褶皱;利用趋势面分析方法给出了两期褶皱的叠加部位及其控矿模型。根据叠加褶皱具等距性控矿特点,笔者预测了已知矿床外围的两个未知矿点,经野外验证和工程揭露表明,上述矿点均见有锑、银矿化。     

Structural characteristics of the rocks of the Delhi Supergroup with special reference to interference patterns: An appraisal with some examples from Central Rajasthan

The rocks of the Delhi Supergroup, which occur around Barr-Sendra and Phulad-Deogarh regions in Central Rajasthan, show three phases of deformational episodes: (i) phase D₁—tight-to-long limbed isoclinal fold (F₁); phase D₂—open, asymmetric fold (F ₂) controlling the map pattern of the formational boundaries; and (iii) phase D₃—major warps (F₃). Interference between nearly coaxial F₁ and F₂ on northerly axes produced hook-shaped and crescent patterns whereas superimposition of easterly trending F₃ on F₂ produced dome-and-basin patterns. The thermal peak was achieved during the second phase of deformation when the rocks were constructively metamorphozed and granites (850−750 m.y.), late synkinematic with respect to second phase of deformation, were emplaced. The sequence of deformation and the structural pattern of the rocks of the Delhi Supergroup in Central Rajasthan strikingly resemble those in northeastern Rajasthan. Structurally the characteristics of the Delhi Supergroup as verified in the entire region from NE to Central Rajasthan are: (a) the same sequence of development of folds, F₁, F₂ and F₃, interspersed with nearly identical phases of recrystallization, (b) hook-shaped interference pattern due to near-coaxial refolding of F₁ by F₂, and (c) variation in axial plunge of F₂ resulting in culminations and depressions. Lastly, phases of the recrystallization history indicates little time gap between F₁ and F₂, and a considerable gap between F₂ and F₃.     

The Songpan-Garze Massif: Its Relation to the QinlingFold Belt and Yangtze Platform and Developmental History

Whether there existed the Songpan-Garze massif is a controversial problem. This paper expounds and proves that the old basement of the massif is represented by the pre-Sinian granitic rock series. This massif and the South Qinling fold belt might both be a part of the old Yangtze platform. Rifting generated by the Caledonian orogeny in the terminal Early Palaeozoic caused the massif to be disintegrated from the northwestern part of the Yangtze platform. This disintegration, however, was not thorough, and the rift troughs were later gradually closed and filled up. The Emei taphrogeny that was initiated in the Early Permian Maokou' an Stage involved a second disintegration of this massif from the Yangtze platform. The rift line largely goes along the Muli-Pingwu line. This rifting belongs to synchronous extensional rifting at peripheries of the Yangtze platform and in its interior, showing that the posterior, lateral and interior extension resulting from rapid northward shift of the Yangtze platform led t     

Constriction structures related to viscous collision,southern Prince Charles Mountains,Antarctica

Macroscopic structures are investigated in a zone of highly contorted migmatites from the southern Prince Charles Mountains, Antarctica. Here, L-tectonite fabrics, rods, mullions, boudin pods, elongate enclaves, and fold hinges, are persistent linear features all plunging gently to the northeast. In contrast, amoeboid folds, ptygmatic folds and folded boudins with different orientations are the characteristic structures in transverse sections (perpendicular to the lineation). No consistent shear sense is recognised in any dimension. Together with strain and shape analysis, these observations strongly suggest that the deformation pattern is one of folding and stretching by constriction. Previous timing constraints indicate that this deformation overlapped with the waning stages of anatexis during decompression at approximately 510 Ma, up to 30 million years after initial orogeny at 540 Ma. The zone affected by constriction is several kilometres wide and has a contorted flower-like shape confined between two broad domal antiforms. In this context, the constricted zone is interpreted as a relatively late tectonic feature that could have formed via deep-seated viscous collision in response to orogenic collapse and doming.     

桓仁地区金属矿床特征及其找矿方向初步探讨

桓仁地区位于辽宁省东部,大地构造位置处于辽东台背斜太子河浑江古坳陷的东端,北邻铁岭―靖宇古隆起,南部与营口―宽甸古隆起毗邻。区内构造异常复杂,各期构造活动均有不同程度的表现,有吕梁期、加里东期、海西期、燕山期等,其中燕山期构造活动尤为突出。区内矿产主要为铜铅锌多金属矿床,类型分为矽卡岩型及热液型两类。矽卡岩矿床呈EW向分布于燕山期侵入岩体周围;热液型矿床主要分布于酸性-碱性侵入体的两侧,呈NE向分布;钼矿不仅呈NE向分布于酸-碱性岩脉两侧,还充填于节理裂隙中。     

内蒙古大梁道班地区叠加褶皱构造分析

内蒙古大梁道班地区位于二连-贺根山缝合带和西拉木伦断裂带之间,区内广泛发育大面积浅变质岩和火山岩。该地区横跨叠加褶皱较为典型,通过1:5万区域地质调查和研究横跨叠加褶皱的几何学、运动学特征,并对其形态、组合关系以及产状要素等进行半定量分析,大量统计与不同期次褶皱相配置的线理和面理数据,利用赤平投影,厘定出本区的三期叠加褶皱变形,同时建立本区的构造变形序列。认为第一期褶皱以区域规模的大型紧闭平卧褶皱为特征;第二期褶皱是在第一期褶皱的基础上发生的横跨叠加褶皱;第三期褶皱是以第二期褶皱轴面劈理和面理在走向上的蛇形弯曲为标志形成的宽缓直立褶皱。