CCSD主孔3000 m岩心构造产状特征及其地质意义

对CCSD主孔3 000 m岩心叶理、具断层擦痕的微断层及断层擦痕产状特征进行了统计分析, 并分析了脆、韧性剪切带的运动学特征, 研究表明(1) 榴辉岩类叶理产状明显较片麻岩类陡, 可能与其岩石能干性较强有关, 因而在挤压褶皱变形过程中表现出不同的变形行为.韧性变形主体表现为顺层剪切, 含断层擦痕的微断层最主要的一组产状与叶理面一致或接近一致, 部分伴随与之呈共轭关系的另一组微断层. (2) 脆、韧性变形以SEE-NWW向剪切为主, 部分为近SN向, 脆性、韧性变形域断层运动方向基本一致.但现在所保留下来的构造变形中韧性变形以SEE向NWW的逆冲型剪切为主, 部分为近SN向韧性剪切作用; 而脆性变形以NWW向SEE的正滑作用为主. (3) 主孔构造应力场初步可划分为4期, 现在所保留的主期构造为SEE-NWW向挤压构造应力场所致.      

低序次韧性断裂的负反转构造研究

赣湘地区的变质核杂岩和变质穹窿构造中，晚期脆性断裂与早期低序次韧性构造间存在着明显的相关联系。这是由于韧性断裂中的面理(S2)，经劈理、节理多次转化，由压性构造转化为张性构造并形成伸展型的脆性断裂。其演化机制在宏观上是碰撞造山形变后期的引张作用；微观上是岩石物体加工硬化的方向性等缘故。并综合分析了在荷载、边界变化的条件下，应力、应变在宏-微观上的重新分配(partitioning)，导致低序次韧性构造向脆性断裂负反转的必然趋势。这方面的研究，不论在资源或是环境地质调查中均有实践意义。     

伸展构造及其反转作用

伸展构造的演化主要发生在三个阶段：大陆裂谷阶段、大陆初始漂移和主要漂移阶段。伸展构造发育在不同构造层次：（１）在上地壳中，伸展构造呈现为位于拆离带之上脆性岩块的伸展，其周边为铲式断层、坡坪式断层或多米诺式断层所限；（２）在中地壳中，伸展构造呈现为变质透镜体，被不连续的韧性剪切带所分隔；（３）在下地壳中，伸展构造呈现为扩展变平的韧性流动和岩浆侵位。反转的伸展断层系常表现为冲断层、断弯背斜、生长断展褶皱、顶部塌陷地堑区的突隆构造和半地堑区的鱼叉构造等。     

基底性质对断裂构造的影响: 以琼东南盆地为例

影响断裂凹陷内的断裂系统演化的原因包含多种因素,此次研究针对先存断裂及基底性质对断陷盆地的影响,通过 物理模拟实验方法探究裂谷盆地断裂发育的构造演化过程。根据对琼东南盆地的地震剖面图的解释分析,盆地东部和西部 的凹陷显示不同的凹陷构造形态,实验结果显示,先存断裂的位置和走向影响区域凹陷的演化和平面展布,在先存断裂影 响的区域演化形成地堑构造,在无先存断裂影响的区域则演化形成地垒构造;韧性基底的上覆地层拉伸演化为复式半地堑 构造,而刚性基底的上覆地层呈铲状半地堑构造,在不同基底性质影响下的构造变形模式和琼东南盆地东西部的差异构造 样式基本相符,一定程度上说明了基底性质的差异对琼东南盆地东部和西部凹陷在断裂组合形态差异方面具有影响作用, 为研究供给油气运移聚集成藏的断裂系统演化提供了思路。     

山东牟乳石英脉型金矿流体成矿构造动力学研究

对金矿床地质地球化学和成矿流体及构造动力学研究认为,石英脉型金矿广泛发育围岩交代作用,在时间上遵循碱金属交代→Ｃａ、Ｆｅ、Ｍｇ中性交代→酸性交代的总体演化序列。与围岩的交代作用,沸腾作用引起的相分离和大气降水的加入所产生的混合稀释是成矿流体体系演化的主要途径,容矿断裂构造活动可划分为脆性破裂和韧脆性扩张两种动力学状态。成矿物质在非平衡和近平衡两种状态交替中分异结晶。流体演化与成矿动力耦合是形成金矿的主要机制。     

煤体脆—韧性变形微观识别标志

以煤体的光学显微镜和扫描电镜观测为主,结合手标本和井下宏观观测,以华北西部部分矿区的主要煤层为研究对象,研究了煤体的脆-韧性变形标志,发现煤体在构造应力的作用下先后经历了脆性、脆—韧性和韧性变形阶段。脆性变形阶段以煤体破裂为主要特征,初期以格里菲斯裂隙为主,后期以剪性裂隙为主,偶尔见张性裂隙。处于脆-韧性变形阶段的煤体脆性和韧性变形的标志共存。典型韧性变形主要集中在糜棱煤中。岩石中发现的韧性变形标志在煤体中,除了重结晶现象,几乎都存在。      

小秦岭金矿田构造演化与金矿成矿作用

依据小秦岭金矿田的地质构造穿插关系和同位素年龄资料,建立了本区构造、岩浆、成矿事件序列。在此基础上,将小秦岭地区的构造演化划分为６个阶段：褶皱变质、韧性剪切变形、稳定升降、韧－脆性断裂转化、断裂活动、抬升剥蚀阶段。对小秦岭金矿田的成矿时代,成矿深度、矿床成因等地质问题,给出了构造地质学方面的判据。     

Tectonic evolution of a crustal-scale oblique ramp,Hellenides thrust belt,Greece

This study investigates the tectonic evolution of the Omalos transverse zone, which served as a crustal-scale oblique ramp in the External Hellenides thrust belt on Crete island. The Omalos oblique ramp developed above an inherited Mesozoic fault zone that strikes NE–SW, oblique to the regional SSW-directed tectonic transport. During the Early Miocene–Pleistocene evolution of the thrust belt, the oblique ramp was repeatedly reactivated localizing deformation above the inherited structure. Geological and structural mapping combined with kinematic analysis of ductile and brittle structures suggest that the Omalos oblique ramp generated a local kinematic field, which deviated significantly from the regional kinematic pattern in the thrust belt. The most conspicuous feature in the tectonic evolution of the oblique ramp is a change from a ductile wrench-dominated to a brittle, primarily reverse faulting regime across the brittle–ductile transition, followed by brittle wrench deformation after the final exhumation of high-pressure (HP) rocks. Deflections of transport and compression orientations from the regional pattern are attributed to buttressing against basement-cover offsets produced by the pre-existing fault zone, to oblique ramping, and to transfer faulting, respectively. Our findings are potentially applicable to other examples of crustal-scale oblique thrust ramps in various tectonic settings.     

阿尔金北缘红柳沟-拉配泉一带铜金矿床硫同位素特征及其意义

通过对阿尔金北缘地区铜金矿床的硫同位素研究, 结合矿床地质特征, 划分了区内矿床的成因类型, 认为主要有3类:似层状海相火山沉积型铜多金属矿床、韧性剪切带型(铜)金矿床、受裂隙控制的脉状岩浆热液型铜多金属矿床。结合区域构造演化特点, 探讨了矿床成因类型与区域构造演化阶段的关系, 认为区域成矿作用可分为3个阶段:第一阶段为早古生代早中期板块构造海底扩张作用时期, 形成以喀腊大湾为代表的海相火山沉积型铜多金属矿床; 第二阶段是早古生代晚期板块构造聚合碰撞作用时期, 形成以大平沟和红柳沟为代表的韧性剪切带型(动力变质热液型)(铜)金矿床; 第三阶段是早古生代末板块构造碰撞后的岩浆活动和偏脆性断裂构造活动时期, 形成以索尔库里北山和拉配泉为代表的受裂隙控制的岩浆热液型铜多金属矿床。从硫同位素特征、矿床成因类型及其与区域构造演化的关系上分析, 该区具有较好的铜金多金属矿床找矿远景。      

江西暖水地区韧性剪切带的基本特征和形变机制

在进行暖水幅1：5万区调时发现江西暖水地区赣东北断裂带中存在外富家坞-枫坡岭、昭林、牛角垄-下石坞三条平行韧性剪切带,为进一步研究暖水地区韧性剪切带岩石、构造形变机制、形成时代特征及与赣东北断裂带的关系,通过地质、岩石矿物、测试分析等综合研究表明,韧性剪切带主要由千糜岩带、糜棱岩带、初糜棱岩带、糜棱岩化带、强片理化带及碎裂岩带组成,其形成经历了早期深层次韧性变形到晚期浅层次脆性变形两个阶段,形成深度10-20km,是赣东北断裂带的主要组成部分,主要变形时代为中晚元古代,与这一时期的华夏板块和扬子板块之间的相互作用有关。     

脉状金矿成矿控矿构造的研究进展

综述了国内外脉状金矿床成矿控矿构造的新近研究成果, 认为脉状金矿床的产出大多与遭受挤压作用所造成的地壳缩短机制有关, 与地壳大规模造山作用过程关系密切,主要产于造山带及其边缘;金元素沉淀的构造部位主要是韧性剪切带中的强变形部位、叠加的韧－脆性和脆性裂隙, 低角度断层既是成矿地球化学界面也是重要赋矿构造;含金成矿流体虽然有多种来源,但构造变形过程中的构造动力分异作用是成矿流体的一种重要成因;成矿流体的运移机制主要受断裂构造控制,高角度逆断层作为阀门引起成矿流体压力的周期性变化, 并导致成矿物质结晶与变形呈同步交替发生;值得进一步深入研究和探讨的问题有金成矿与深部构造的关系、低角度断层的成生演化与金成矿物理化学场耦合关系、构造动力变形作用引发含金热液形成的高温高压成矿实验以及韧性剪切带的四维控矿机制等。     

内蒙古西部英巴地区晚古生代-中生代构造岩浆事件及其地质意义

本文以内蒙古西部英巴地区一个典型剖面为例,开展了详细的构造解析和年代学研究,初步构建这一地区晚古生代-中生代的构造岩浆事件框架。这一地区至少发育三期岩浆活动和三期构造变形事件。锆石U-Pb定年结果和前人的资料显示,三期岩浆活动分别为石炭纪（325~313 Ma）的花岗闪长岩和花岗岩、早二叠世（291~277 Ma）的钾长花岗岩和中细粒花岗岩及早白垩世（~134~130 Ma）的伟晶岩和石英二长岩。第一期构造变形事件为NW-SE向挤压,发生在早二叠世之后,使花岗闪长岩和钾长花岗岩发生挤压变形,形成主体低角度北西倾的片麻理,局部发育同期褶皱,变形温度为450~600℃;第二期为NW-SE向伸展,大致发生在早白垩世,使片麻状花岗闪长岩和片麻状钾长花岗岩发生中高温（450~650℃）的糜棱岩化作用,形成南东倾的低角度韧性剪切带,具有正断性质,后被伟晶岩脉切穿。第三期为NW-SE向伸展,发生在早白垩世之后,形成北西倾的中角度脆性正断层,断距2~10米,并使伟晶岩变形为碎裂岩。     

辽东鞍山齐大山韧性剪切带运动学解析及形成机制

关于太古宙早期地壳演化构造机制的争论已经持续了数十年,其焦点主要集中于水平构造还是垂向构造两大经典构造模式的探讨.对于早期地壳构造演化方面的研究,将会有助于我们更好地理解早前寒武纪的地球动力学机制.本文对华北克拉通东北部鞍山地区花岗-绿岩带内齐大山韧性剪切带的构造变形特征进行了详细的解析,揭示了该区新太古代垂向构造作用样式.研究结果表明,齐大山韧性剪切带内花岗质岩石长英质矿物塑性拉长特征明显,条带状构造发育,面理向NWW方向陡倾,不对称组构特征和矿物拉伸线理产状指示向NWW的陡倾正滑移剪切作用.变形岩石中的长英质矿物均发育中低温显微变形特征,石英C轴电子背散射衍射（EBSD）组构分析揭示石英以菱面＜a＞和底面＜a＞滑移系为主,岩石经历了中低温非共轴变形.根据矿物的变形行为以及石英的结晶优选方位推测变形温度约为400~500℃,岩石变形特征以位错蠕变为主.有限应变分析结果表明,靠近铁矿带方向,构造岩类型由L=S构造岩过渡为LS构造岩,岩石应变强度呈明显增强趋势.运动学涡度测量结果显示齐大山韧性剪切带内大多数岩石样品的W_k值大于0.75,岩石形成于以简单剪切作用为主的一般剪切作用.对比花岗-绿岩带西侧的白家坟韧性剪切带,显示二者均具有相向的陡倾正滑移运动学特征,表明新太古代时期鞍山地区地壳构造演化模式以垂向构造作用为主.      

秦岭镇-旬地区微细浸染型锑金矿床成矿条件及其找矿前景分析

镇（安）旬（阳）地区锑金矿化分布，与其区域地质地球化学因素，陆源断陷盆地沉积岩相变化，后期构造作用密切相关，认为镇旬地区为扬子与华北板块边缘对接过渡活动带，形成局部扩张断陷沉积盆地环境。海底同生断裂的发育，使盆地中心局限台盆环境造成陆源物质、内源组份和深部物质的混生，以及为深部含矿热液上升提供通道；在后期脆－韧性剪切变形构造叠加，地下热卤水循环改造作用，形成层控式细脉浸染型锑金矿床。该地区锑金成矿物质来源丰富，沉积构造环境优越，后期控矿构造发育，显示了潜在的细脉浸染型锑金矿床的找矿前景。     

断层岩与断层模式

本文通过对断层岩的结构、构造特征及其力学成因研究现状的综述，提出以下几点看法：（１）断层岩是在特定的地质环境下形成的，其结构特征直接反映所处境的地质构造运动特性所以通过研究断层岩的内部组构可以直接了解形变环境及其区域地质构造发展史；（２）断层财的线理和面理结构既可以在韧塑性条件下形成，也可以在脆性条件下形成，因此是否具有线理与面理结构不能作支岩分类的决定性基准；（３）断层岩母岩结晶的大小直接影响断     

Superimposed tectonic and hydrothermal events during the late-orogenic extension in the Western French Massif Central: a structural and 40Ar/39Ar study

In the Western French Massif Central, the Argentat fault is a major structure through which As–Au fluids percolated in the Late Carboniferous along brittle fractures. New petrostructural investigations show that an early ductile normal-dextral faulting, coeval to leucogranite emplacement took place during the Late Visean syncollisional extension of the belt and was accompanied by a hydrothermal event marked by the growth of muscovites whose ⁴⁰Ar/³⁹Ar ages cluster around 335 Ma. This early fluid channelling is associated with brittle deformation only in the hangingwall of the Argentat fault, whereas ductile deformation is restricted to the footwall. These results provide new evidence for the upper crust implication during the syncollisional extension in the French Massif Central. This study stresses the interest of a detailed multimethod analysis to characterize hydrothermal processes, especially in basement areas where the tectonic, plutonic and metamorphic evolution is polyphased.     

Evolution of volcanism in graben and horst structures along the Cenozoic Cameroon Line (Africa): implications for tectonic evolution and mantle source composition

Tombel graben and Mounts Bambouto are two volcanic fields of the typical system of alternating graben and horst structure of the Cameroon Volcanic Line. Tombel graben is a young volcanic field, whereas Mounts Bambouto horst is an old stratovolcano with calderas. Volcanic products in both settings have a signature close to that of Ocean Island Basalt implying a major role of FOZO (focal zone) component and varied contribution of depleted mantle (DMM) and enriched mantle (EM) components. The Cameroon Volcanic Line is a hot line essentially resulting from passive rifting. Eocene to Recent intraplate basaltic volcanism in the study area was probably a result of mantle upwelling coupled with lithospheric extension. The olivine basaltic magma of horst volcanoes evolved in a large-scale, steady-state magmatic reservoir via crystal fractionation and limited contamination to highly differentiated alkaline lavas (trachyte and phonolite). Conversely, rapid ascent of lavas along multiple fault lines of graben structures produced less evolved lavas (hawaiite) within small reservoirs. This model, evaluated for the study area, involves mantle upwelling inside zones of weakness in the lithosphere after intra-continental extension. It can be applied to other parts of the Cameroon Volcanic Line as well, and is similar to that described in other intra-continental rift-related areas in Africa.     

安徽桐城挂车河镇地区韧性剪切带元素质量平衡分析

韧性剪切变形对岩石地球化学行为的制约一直是地质学家们关注的问题。安徽桐城挂车河镇（挂镇）地区是大别造山带东缘和郯庐断裂带交汇位置,两个构造体系的韧性剪切带均发育,为开展对比分析研究提供了条件。不同构造体系及构造期次的长英质韧性剪切带在糜棱岩化过程中体积变化和元素迁移规律均相似,随着变形强度的增加。体积亏损和元素迁移越明显,体积亏损可达32．18％,元素迁移表现为SiO2、K2O、Na2O的迁出和Fe2O3、CaO、MgO的迁入;镁铁质脆一韧剪切带在糜棱岩化过程中体积变化和元素迁移规律与长英质剪切带的恰恰相反,体积增加21．63％～186．60％．元素迁移的显著特征是SiO2大量迁入及Fe2O3和CaO迁出。     

Deformation Style of Slickenlines on Mélange Foliations and Change in Deformation Mechanisms Along Subduction Interface: Example from the Cretaceous Shimanto Belt, Shikoku, Japan

Accretionary complexes record the histories of changes in physical properties of sediments from unlithified sediments to lithified rocks through the deformation processes along subduction interface. The trench sediment suffered various deformation of particulate flow, pressure solution deformation and cataclastic faultings from ductile to brittle regime during accretion in subduction zone. Tectonic mélange is a characteristic rock in on-land accretionary complexes. The dominant deformation mechanism of tectonic mélange formation is pressure solution on the basis of microscopic observation. However, brittle slickenlines are also commonly observed on mélange foliations at the outcrop scale. Although the slickenlines as a brittle failure is common on the surface of the pressure solution foliation, the relationship of their kinetic are still uncertain. Detailed observations of slickenlines suggest that they are formed by reactivation of the mélange foliations, which indicates that the slickenlines are developed after formation of block in matrix texture characterized in mélange. In addition, mélange foliations are cut by faults related to underplating of oceanic materials. Therefore, formation of slickenlines occur before underplating in a relatively deep portion along subduction interface. On the basis of P-T conditions reported from other parts of the Cretaceous Shimanto Belt, the mélange formation and underplating is inferred to have occurred around the seismic front or within the seismogenic zone. The change in deformation mechanisms from pressure solution to brittle failure may be the first change in physical properties from plastic to brittle around seismic front.