首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 125 毫秒
1.
脆、韧性变形构造煤的激光Raman光谱特征及结构成分响应   总被引:1,自引:0,他引:1  
对淮北煤田不同类型构造煤进行了激光Raman光谱分析,探讨了不同变形机制下构造煤结构成分的变化特征.结果表明,各类构造煤均存在两个主要的Raman振动区域(G峰和D峰),分别位于1590.3-1600.1cm^-1和1340.3—1356.9cm^-1,脆、韧性变形构造煤随着变质和变形程度的增加,表现出明显不同的光谱特征.脆性变形构造煤,随着变质、变形程度增加,光谱特征峰明显增强,D峰峰位向低波数偏移;韧性变形构造煤(糜棱煤)的特征峰则随之减弱,D峰峰位向高波数偏移;脆韧性变形构造煤则先类似于脆性变形、而后表现为韧性变形的变化特征.进而从分子水平上,探讨了造成脆性变形与韧性变形构造煤激光Raman光谱不同变化特征的原因.  相似文献   

2.
位于大别造山带北部的晓天—磨子潭断裂带分隔了北大别高级变质带和北淮阳浅变质带.该断裂带由韧性剪切带和脆性正断层组成,两者具有基本一致的NW—SE向走向.脆性正断层叠加在韧性剪切带之上,控制了其北侧的早白垩世火山岩盆地的发育,为大别造山带早白垩世穹窿过程中的伸展断层.晓天—磨子潭韧性剪切带叠加在北大别灰色片麻岩之上.糜棱岩中的矿物变形温度估计(600—650℃)、基质多硅白云母探电子针分析及压力计算(约1.1GPa),指示韧性剪切带形成于高角闪岩相的下地壳深度,为造山带同碰撞折返边界.韧性剪切带糜棱面理上的矿物拉伸线理侧伏角自东向西逐渐由水平过渡到近倾向.露头构造、显微构造及石英C轴组构皆指示该韧性剪切带具有上盘向北西的运动方向.韧性剪切带几何学与运动学特征指示,大别造山带高压—超高压岩片的折返是向南东的斜向挤出,并兼有折返岩片以东端为枢纽的逆时针旋转.  相似文献   

3.
河南熊耳山地区的滑脱拆离带由浅部到深部为一脆性—脆韧性—韧性的断裂带.浅部盖层由于未遭受高温热液变质作用,所受围压和孔隙压力较小,表现为脆性变形;深部基底遭受了强烈的高温热液变质作用,岩石中赋存汽水流体较多,所受围压也较大,表现为韧性变形;而位于盖层与基底之间的拆离断层则由于高孔隙压力作用降低了部分围压效应,使之位于盖层与基底之间的拆离断层产生了脆韧性变形.这样在不同围压、流体、孔隙压力和高温热液变质作用等因素及构造应力的共同作用下,实现了本地区滑脱拆离带的脆韧性转换  相似文献   

4.
龙门山岩石圈地壳三维结构及汶川大地震成因浅析   总被引:12,自引:0,他引:12  
地质构造研究和地震测深剖面的构造解析显示,龙门山碰撞遣山带岩石圈存在既有显著差异又有密切联系的两套断裂系统:一是以地壳表层脆性剪切带为主的浅层断裂系统;另一是以切割莫霍界面或壳幔过渡带的壳幔韧性剪切带为主的深部断裂系统.根据地质构造和地震测深成果的综合研究,在建立起龙门山遣山带及邻区岩石圈地壳结构模型的基础上,论述了两套断裂系统的特征与相互关系,提出岩石圈壳幔韧性剪切带可能是四川汶川8.0级强烈地震的发震构造之一,以及强烈地震形成的动力学模式等.  相似文献   

5.
舒家坝-太阳寺断裂构造地质特征及其控矿作用   总被引:1,自引:0,他引:1  
余超 《甘肃科技》2004,20(9):131-134
舒家坝 -太阳寺断裂是丹风群与舒家坝群的边界脆韧性断裂带。该断裂有早期脆韧性和晚期脆性叠加的多期活动特征。断裂在娘娘坝 -舒家坝一带呈反S型展布 ,断带内发育糜棱岩和构造砾岩 ,并且部分成矿元素富集 ,对区内多金属矿床的形成和分布具控制作用。断裂带北侧分支断裂中已发现多处多金属矿床 (点 )  相似文献   

6.
作为武当山大型推覆体内部紫金断片构造边界的紫金韧性剪切带具有复合性质,曾先后经历了自北而南的韧性推覆—北东向脆、韧性左行走滑—北东向韧、脆性右行走滑—脆性张破裂及平移。韧性剪切带的演化与武当山推覆构造的递进变形密切相关。  相似文献   

7.
龙门山冲断带分段-分带性构造格局及其差异变形特征   总被引:18,自引:0,他引:18  
龙门山冲断带地处青藏高原东缘,介于松潘-甘孜褶皱带与四川盆地之间,由一系列走向北东、倾向北西的逆冲断层及其所夹的岩片组成.分段一分带性构造格局是龙门山冲断带的基本特点和重要特色.龙门山自西向东发育有4条主干断裂:茂县-汶川断裂、北川-映秀-五龙断裂、安县-都江堰(原称"灌县")-双石断裂和广元-大邑-雅安(隐伏)断裂.由这些主干断裂分隔,龙门山冲断带沿倾向表现出明显的分带性变形特征,以其典型构造特征自西向东称为弧形韧性变形带、基底冲断-同劈理褶皱带、同心褶皱-叠瓦冲断带、前陆扩展变形带和前陆坳陷带,它们自西向东显示层次渐浅、韧性递减、脆性渐强的变形特点.龙门山冲断带沿走向以北川-安县与卧龙-怀远-线为界可三分为北段、中段和南段,北段以出露轿子顶基底杂岩和唐王寨向斜及其前缘叠瓦冲断系为主要特征,中段以出露彭灌基底杂岩及其前缘发育飞来蜂为典型特征,南段以出露五龙、宝兴基底杂岩及其前缘发育飞来蜂为典型特征.自北东向南西,龙门山冲断带沿走向具有构造起始和定型时期渐晓、脆性渐强、前陆卷入变形的程度渐强、新生代隆升渐快和活动性增强的变化趋势.  相似文献   

8.
徐家堡子地区以黑云英云闪长质片麻岩(2.47Ga)为围岩的上壳岩(〉2.98Ga)包体中,发育几条近东西走向的韧性变形变质带(2.7Ga)。研究表明,该韧性变形变质带在平面和剖面上的均呈舒缓波状,发育糜棱叶理,矿物线理和S-C组构。带内的糜棱片麻央矿物成分复且多世代矿物共存,变形前以石榴石,黑云母,斜长石和石英矿物组合为代表,形成温度为500~520℃,压力为0.4GPa;韧性变形同期以夕线石,石  相似文献   

9.
内蒙赤峰南部楼子店拆离断层系绿泥石化带的形成时代   总被引:7,自引:0,他引:7  
楼子店拆离断层系是华北陆块北缘一条大型北东南西向构造,低角度倾向南东.拆离断层系中韧性剪切带的走向线理与脆性断面上的倾向擦痕表明该断层发育过程中发生了运动学上的转向.拆离断层系绿泥石化带是伸展过程中构造层次递进变浅所致的退化变质作用产物,其中发育了早期近走向和晚期倾向两组线理,记录了上盘早期向北东的韧性剪切到晚期脆性倾向下滑的运动学转向过程.因此,绿泥石矿物的定年可限定这一构造热事件及运动学转向的时间.初步的绿泥石K-Ar定年表明,楼子店拆离断层系绿泥石化带形成始于~121Ma,114—112Ma间发生了运动学的转向.  相似文献   

10.
那拉提构造带位于天山西段伊犁盆地与南天山之间 ,出露宽度约 2 5 km,由早元古代片岩、片麻岩及混合岩、混合花岗岩组成 ;深层次韧性剪切带及叠加中 -浅层次剪切带发育 ;那拉提构造带南缘断裂明显 ,南侧为古生代浅变质黑色岩系 ;构造带北缘韧 /脆性剪切带宽度大 ,两侧岩石劈理化后易于混淆 ,故界线不明显。那拉提构造带基本地质特征可与邻国中天山对比 ,存在寻找国外类似大型金矿床的条件和可能  相似文献   

11.
The Yunmengshan metamorphic core complex in the middle part of the Yanshan Fold and Thrust Belt records crust extension processes of the eastern North China Craton during its peak destruction.Development of the metamorphic core complex was controlled by the generally NNE-striking Dashuiyu Shear Zone.The shear zone dips SE and becomes shallower NE-wards,leading to exposures of a ductile shear zone in the southern and middle parts and brittle faults in the northern part.Exposure structures,microstructures,and quartz C-axis fabrics indicate that the ductile shear zone belongs to an extensional shear zone with a top-to-the-SE shear sense.Deformation temperatures of 300–520°C suggest a midcrustal origin for the ductile shear zone.A ductile deformation belt in the footwall of the shear zone is only as wide as 1–3 km,indicating no widespread mid-crustal ductile flow in the region during the deformation.Zircon U–Pb dating of dykes and plutons as well as hornblende and biotite40Ar/39Ar dating demonstrate that the metamorphic core complex originated at 135 Ma and experienced intense shearing of the Dashuiyu Shear Zone,development of the supradetachment basins,and synkinematic intrusion during 135–125 Ma.The metamorphic core complex was subjected to rapid exhumation during 125–114 Ma when the Dashuiyu Shear Zone suffered continuous activity and passive doming.The shear zone and its hanging wall were cut or replaced by a series of brittle faults when they wereuplifted to a brittle regime,showing that exhumation took place in continuous extensional activities.The metamorphic core complex turned into slow exhumation in an extensional regime in the following latest Early Cretaceous.The evolution history suggests that the Yunmengshan metamorphic core complex was developed by the rolling-hinge model,a common formation mechanism for intraplate metamorphic core complexes in the North China Craton,under the continuous NW–SE extension during the Early Cretaceous(135–100 Ma).  相似文献   

12.
商南-商城断裂带中段的韧性剪切带是由多条糜棱岩带及其所夹的变质岩块体组成的大型韧性剪切带。它是以简单剪切为主要变形机制的、于绿片岩相温压条件下形成的韧性剪切带。剪切带内糜棱岩的塑性变形和恢复重结晶作用强烈。糜棱叶理产状多较陡倾,a线理近水平,表明为走滑断裂。大量不对称旋转构造指示该剪切带早期为左行剪切,后期在不同地段又叠加上程度不同的右行剪切  相似文献   

13.
依据龙门山中段映秀断裂带构造岩的宏观地质特征、显微构造及组构特征,论证了构造岩具有脆性和韧性两大类型,形成序次上为先韧性后脆性。映秀断裂带是在长期持续推覆作用下形成的一条脆、韧性道冲构造。文章还讨论了断裂带形成的构造环境和演化机制。  相似文献   

14.
An ultrahigh pressure ductile shear mélange crops out on the beach of Yangkou Bay near Qingdao City. The mélange is composed of weakly deformed blocks in a highly ductilly flow mylonites. Ultrahigh pressure metamorphic (UHPM) tectonite includes strongly deformed eclogite and mylonitized eclogite. Coesite occurs in the tectonite as both interstitial mineral and inclusions in garnet and omphacite, indicating that the deformation took place in the stability field of coesite (800—850℃, >30 GPa) in the upper mantle. Coesite is rounded or short prismatic grains with undulatory extinction, and often fractured, suggesting brittle deformation. Garnet is also characterized by brittle fractures and sometimes necked and slightly elongated. Omphacite is elongated, with long axis preferred orientation. Undulatory extinction, subgrains and dynamically recrystallized grains suggest plastic flow of omphacite. Ultrahigh pressure metamorphic tectonite was probably formed in the ductile shear zone during the early stage of exhumation of the ultrahigh pressure metamorphic rocks. Its kinematic indicators point to the transport direction of the UHPM slab during the early stage of exhumation.  相似文献   

15.
秋格明塔什-黄山韧性剪切带构造变形序列   总被引:1,自引:0,他引:1  
运用构造解析方法和应变测量与显微构造分析方法,研究了秋格明塔什-黄山韧性剪切带的构造样式,建立了其变形序列。该带依次经历了:(1)中深部构造层次的紧闭同斜褶皱作用;(2)中深部构造层次的顺层(片)韧性剪切变形;(3)中部构造层次的右行走滑脆-韧性剪切变形;(4)中浅构造层次的膝折作用。  相似文献   

16.
讨论了彭灌断裂带的宏观及微观变形特征。宏观构造、显微构造特征反映出该断裂带为一条脆性逆冲推覆断裂,其变形机制主要为碎裂作用。断层主要产于中生代地层之中,并有叠置的推覆岩片夹于其中,主要活动时期是在喜马拉雅期。  相似文献   

17.
The Xiaotian-Mozitan fault (XMF) located north of the Dabie orogenic belt separates the North Dabie complex to the south from the Beihuaiyang low-grade metamorphic rocks to the north. It comprises several NW-striking ductile shear zones and brittle faults. The brittle faults obviously overprinted on the ductile shear zones and promoted the development of the volcanic basins in early Cretaceous to the north, which suggests that the brittle faults were normal faults formed in early Cretaceous during doming of the Dabie orogenic belt. The ductile shear zone superposed on the north Dabie gray gneiss, and it is an important channel where the Dabie HP-UHP rocks exhumed. For obtaining new structural constraint on exhumation of the HP-UHP rocks, we present here experimental results on the microstructure, quartz C-axis fabrics and the microprobe analyses of phengite. The ductile shear zone was determined to be formed at a temperature of 600-650 ℃ and pressure of 1.1 GPa by the mineral deformation, microprobe analyses and geobarometry of Si-in-phengite of the mylonite, the results suggest that the mylonite now exposed on the surface experienced an upper amphibolite-facies metamorphism in the lower crust. The mineral stretching lineation varies from horizontal in the east segment to sub-dip in the west. Shear sense indicators from outcrop and thin sections of orientated specimen and quartz C-axis fabrics suggest that the XMF is a sinistral normal fault. The kinematics analysis of the ductile shear zone indicates that the exhumation of Dabie HP-UHP rocks is the results of a SE-directed extrusion and an anticlockwise rotation around its eastern pivot simultaneously.  相似文献   

18.
There are a lot of important gold_bearing quartz veins in the Xiaoqinling metamorphic core complex. The quartz veins are strictly controlled by shear zones. Stress analysis indicates that the metallizing process of the Xiaoqinling gold deposits of quartz vein type can be divided into two stages. At the first stage, the shear zones were formed in an extensional environment, and the temperature was higher and the buried depth was greater; at the second stage, the brittle thrusts were superimposed in ductile shear zones after the tectonic stress field turned from the extension to compression. The ore_bearing fluids were concentrated in these weak positions, and the gold deposits of quartz vein type were developed.  相似文献   

19.
内蒙古霍各乞矿区狼山群伸展构造及其控矿作用   总被引:3,自引:0,他引:3       下载免费PDF全文
张明华  王春增 《广西科学》2002,9(3):188-192,197
对内蒙古霍各乞矿区内面理、线理、褶皱、断裂构造进行多层次、多尺度、详细的构造解析发现,内蒙古霍各乞矿区狼山群早期存在明显的伸展变形,广泛出现顺层面理。在狼山群第三岩组中发育韧性剪切带、糜棱岩、顺层掩卧褶铍及石香肠构造。霍各乞矿田含矿岩系实际上是变形较强的顺层韧性剪切带,矿床或矿体最初在韧性剪切带及顺层面理中富集成矿,形成浸染状、层状、条带状、块状矿化。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号