华北上地壳构造单元划分          下载免费PDF全文

李涛  王宗秀 《地学前缘》2009,16(4):215-224

利用天然地震数据分析研究得到的中地壳滑脱层的深度、活动方式、强度等结果,与重磁异常基底解译成果相结合,提出华北地区在中地壳位置发育有区域滑脱面,其特定壳层及深度位置决定了其在华北深浅构造关系转换中,起着“屏蔽”或联系的重要作用,而在华北伸展变形中是地块运动变形的底边界面。上地壳各个部分在沿其滑动时,因速度差、侧向约束条件等的不同,而派生出断叉线、横向调整断裂及相应的凸起、凹陷断块等次级单元。它们构成了华北上地壳基本构造单元,并直接控制着盆山空间分布、构造地貌单元发育。研究提出了华北上地壳构造单元划分方案:上地壳基底构造分为9个一级单元(Ⅰ~Ⅸ)和23个二级单元。其中一级构造单元为:Ⅰ阴山北部东西向区域凹陷断块;Ⅱ阴山-燕山区域凸起断块;Ⅲ太行山区域凸起断块;Ⅳ大别山区域凸起断块;Ⅴ渤海湾盆地断坳、断隆区;Ⅵ南华北盆地断坳、断隆区;Ⅶ鲁西区域断隆区;Ⅷ下扬子区域断坳、断隆区;Ⅸ鄂尔多斯区域断坳区。  相似文献   

聂拉木地区高喜马拉雅岩石磁组构及其构造含义   总被引：5，自引：2，他引：3       下载免费PDF全文

李建忠  潘忠习  冯心涛  庄忠海  朱同兴  邹光富 《地球物理学报》2006,49(2):496-503

利用岩石磁化率量值椭球体与岩石构造应变椭球体的共轴性,在缺乏岩性标志层的高喜马拉雅结晶基底（聂拉木地区）进行岩石磁组构研究,进而研究喜马拉雅造山带的变形期次和过程.磁组构特征表明：磁化率各向异性度P在樟木镇北1km处的片岩最高为172,在康山桥南1km处最低,为113;百分率各向异性度H在1182%～4507%之间;磁性线理L在102～109之间,磁性面理F在106～160之间,磁性面理F比磁性线理L发育;磁化率椭球体的形状因子T在019～076之间,磁化率椭球的扁率E在104～149之间,磁化率椭球体的形状为一压扁椭球;樟木镇北1km到肉切村,平均最小磁化率主轴方向D3为S－N（除聂拉木北1km的MA9外）,大多数样品最小磁化率主轴方向倾角I3＞51°,最高达726°,局部发育有拉长形磁化率量值椭球体.本文研究结果表明,聂拉木地区早期经历强烈的韧性变形,推测可能是一条巨大的右旋逆冲韧性变形带,晚期构造掀斜.  相似文献   

河南木厂河区银、金、铜矿床的构造控矿特征     

李毅  胡海珠 《地质力学学报》2006,12(3):345-353

河南木厂河地区,位于秦岭-大别山中央造山带的东部,桐柏-大别构造亚带东段。区内以长期活动的NWW-近EW向深大断裂及派生的NWW向,SN向断裂以及平行于东部郯庐断裂带的NE向断裂为主要特征,褶皱表现为形态复杂的宽缓线形。通过调查研究,确认了木厂河矿区存在三个构造岩石单元:核杂岩单元(CC)、超高压单元(UHP)、高压单元(HP).各单元之间发育有大型的拆离断层,有利于成矿元素富集。本区矿床的形成与大别山超高压变质带折返后的伸展拆离作用密切相关。矿体形成部位主要在核杂岩单元之上,超高压单元之下的拆离断层带。拆离断层对本区的矿化起了重要的控制作用。   相似文献   

三门峡断陷盆地及邻区深部结构及成因——来自深地震反射与大地电磁测深的证据     

何发岐  於文辉  马超  张世晖  黎小伟  刘德民 《地质学报》2024,98(4):1088-1100

近年来,围绕三门峡断陷盆地中的油气、地热资源做了大量的工作,成因机制研究较少,严重制约了矿产资源的勘探开发。本文在前人研究工作基础上,结合野外地质调查并利用高精度深反射地震剖面、大地电磁（MT）、重磁等地球物理探测技术,对三门峡盆地进行综合研究。发现三门峡盆地主要由东、西2个负花状构造构成,西花状构造体大于东花状构造体;盆地东部边缘以观音堂隆起与洛阳凹陷相邻,观音堂隆起发育有壳内透镜状低速体,其东、西两侧均发育有规模较大的隐伏逆断层。研究区内莫霍面为大约5 km厚度滑脱层,在深反射地震剖面上表现为蚯蚓状反射特征,指示滑脱层为西向运动。莫霍面滑脱层上部与下部新发现多条弧形断层。地质与地球物理资料综合研究表明,莫霍面滑脱层的解耦作用是三门峡断陷盆地花状构造形成的主因;在不同时空构造力系作用下,形成研究区新生代全地壳旋转花状构造盆地。  相似文献   

Quantifying the effects of plant litter in the topsoil on the soil detachment process by overland flow in typical grasslands of the Loess Plateau,China     

Jia-Xin Liu  Pan-Pan Li  Guo-Bin Liu  Dennis C. Flanagan 《水文研究》2020,34(9):2076-2087

Plant litter can be incorporated into topsoil by a natural process, affecting the soil erosion process. This is a widespread phenomenon in erosion-prone areas. This study was conducted to investigate the effect of litter incorporation on the process of soil detachment on the Loess Plateau, China. Four common plant litters (Bothriochloa ischaemum L. Keng., Artemisia sacrorum Ledeb., Setaria viridis L. Beauv., and Artemisia capillaris Thunb.) were collected, then incorporated into the silt loam soil at five rates (0.1, 0.4, 0.7, 1.0, and 1.3 kg m⁻²) on the basis of our field investigation. Twenty litter–soil treatments and one bare soil control were prepared. After 50 days of natural stabilization, 30 soil samples of each treatment were collected. We used a flume test to scour the soil samples under six flow shear stress conditions (5.66, 8.31, 12.21, 15.55, 19.15, and 22.11 Pa). The results showed that the different incorporated litter masses and morphological characteristics, such as litter tissue density (ranging from 0.52 to 0.68 g cm⁻³), length density (2.34 to 91.00 km m⁻³), surface area density (LSAD; 27.9 to 674.2 m² m⁻³), and volume ratio (0.003 to 0.050 m³ m⁻³), caused varied soil detachment capacities (0.043 to 4.580 kg·m⁻²·s⁻¹), rill erodibilities (0.051 to 0.237 s m⁻¹), and critical shear stresses (2.02 to 6.83 Pa). The plant litter incorporated within the soil reduced the soil detachment capacities by 38%–59%, lowered the rill erodibilities by 32%–46%, and increased the critical shear stresses by 98%–193% compared with the bare soil control. The soil containing B. ischaemum (L.) Keng. litter was more resistant to erosion. By comparing different parameters, we found that the contact area between the litter and soil was the main factor affecting the soil detachment process. The soil erosion resistance increased with the increasing contact area between the soil and litter. Furthermore, the litter incorporation effect on rill erodibility can be comprehensively reflected by LSAD (R² = .93; Nash–Sutcliffe efficiency = 0.79), which could be used to adjust the rill erodibility parameter in physical process-based soil erosion models.  相似文献   

GEOPHYSICS     

《Abstract of Chinese Geological Literature》2014,(3)

正20141316 Chen Qiangsen(School of Earth Sciences and Engineering,Nanjing University,Nanjing 210093,China);Bao Xuewei The Crustal Velocity Structure of the Ordos Block and Its Southern Edge Revealed from the Ambient Seismic Noise Extraction(Geological Journal of China Universities,ISSN1006-7493,CN32-1440/P,19(3),2013,p.504-512,7 illus.,33 refs.)  相似文献   

Main Structural Styles and Deformation Mechanisms in the Northern Sichuan Basin, Southern China   总被引：3，自引：2，他引：1  

TANG Liangjie  GUO Tonglou  JIN Wenzheng  YU Yixin  LI Rufeng 《《地质学报》英文版》2008,82(3):543-553

The Triassic Jialingjiang Formation and Leikoupo Formation are characterized by thick salt layers. Three tectono-stratigraphic sequences can be identified according to detachment layers of Lower-Middle Triassic salt beds in the northern Sichuan Basin, i.e. the sub-salt sequence composed of Sinian to the Lower Triassic Feixianguan Formation, the salt sequence of the Lower Triassic Jialingjiang Formation and Mid-Triassic Leikoupou Formation, and the supra-salt sequence composed of continental clastics of the Upper-Triassic Xujiahe Formation, Jurassic and Cretaceous. A series of specific structural styles, such as intensively deformed belt of basement-involved imbricated thrust belt, basement-involved and salt-detached superimposed deformed belt, buried salt-related detached belt, duplex, piling triangle zone and pop-up, developed in the northern Sichuan Basin. The relatively thin salt beds, associated with the structural deformation of the northern Sichuan Basin, might act as a large decollement layer. The deformation mechanisms in the northern Sichuan Basin included regional compression and shortening, plastic flow and detachment, tectonic upwelling and erosion, gravitational sliding and spreading. The source rocks in the northern Sichuan Basin are strata underlying the salt layer, such as the Cambrian, Silurian and Permian. The structural deformation related to the Triassic salt controlled the styles of traps for hydrocarbon. The formation and development of hydrocarbon traps in the northern Sichuan Basin might have a bearing upon the Lower-Middle Triassic salt sequences which were favorable to the hydrocarbon accumulation and preservation. The salt layers in the Lower-Middle Triassic formed the main cap rocks and are favorable for the accumulation and preservation of hydrocarbon.  相似文献   

Basin- and Mountain-Building Dynamic Model of “Ramping-Detachment-Compression” in the West Kunlun-Southern Tarim Basin Margin     

CUI Junwen  LI Pengwu  GUO Xianpu  DING Xiaozhong  TANG Zhemin 《《地质学报》英文版》2008,82(2):358-370

Analysis of the deformation structures in the West Kunlun-Tarim basin-range junction belt indicates that sediments in the southwestern Tarim depression were mainly derived from the West Kunlun Mountains and that with time the region of sedimentation extended progressivdy toward the north. Three north-underthrusting （subducting）, steep-dipping, high-velocity zones （bodies） are recognized at depths, which correspond to the central West Kunlun junction belt （bounded by the Kiida-Kaxtax fault on the north and Bulungkol-Kangxiwar fault on the south）, Quanshuigou fault belt （whose eastward extension is the Jinshajiang fault belt） and Bangong Co-Nujiang fault belt. The geodynamic process of the basin-range junction belt generally proceeded as follows： centering around the magma source region （which largely corresponds with the Karatag terrane at the surface）, the deep-seated material flowed and extended from below upward and to all sides, resulting in strong deformation （mainly extension） in the overlying lithosphere and even the upper mantle, appearance of extensional stress perpendicular to the strike of the orogenic belt in the thermal uplift region or at the top of the mantle diapir and localized thickening of the sedimentary cover （thermal subsidence in the upper crust）. Three stages of the basin- and mountain-forming processes in the West Kunlun-southern Tarim basin margin may be summarized： （1） the stage of Late Jurassic-Early Cretaceous rampingrapid uplift and rapid subsidence, when north-directed thrust propagation and south-directed intracontinental subduction, was the dominant mechanism for basin- and mountain-building processes; （2） the stage of Late Cretaceous-Paleogene deep-level detachment-slow uplift and homogeneous subsidence, when the dominant mechanism for the basin- and mountain-forming processes was detachment （subhorizontal north-directed deep-level ductile shear） and its resulting lateral propagation of deep material; and （3） the stage of Neogene-pre  相似文献   

北祁连造山带西段前造山期伸展构造特征——以肃北县鱼儿红地区为例     

王永和  孙南一 《西北地质》2001,(4)

北祁连山是著名的加里东期造山带 ,以往地质研究主要集中在建造和主造山期板块俯冲 -碰撞及陆内造山构造方面。作者通过在北祁连山西段区调填图 ,发现了一套基本顺层发育的拆离滑脱正断层、顺层韧性剪切带、流劈理及掩卧褶皱等 ,笔者对其构造样式、组合关系、运动学、动力学特征和相关建造的发育等进行了阐述、分析与讨论 ,认为它们是与前造山期裂谷盆地建造发育密切相关的同构造正断层型伸展构造群落。  相似文献   

太行山中北段拆离带型金矿的成矿作用研究     

牛树银  孙爱群 《华北地质矿产杂志》1997,12(1):67-74

阜平、赞皇隆起是太行山区中新生代伸展体制控制的变质核杂质，变质核杂岩的强烈隆升和东、西两邻断陷的大幅度沉降，在变质杂岩核的外围形成长期活动的正向拆离滑脱带。金很容易在拆离滑脱带中迁移，聚集成矿，为此，本文依据已有研究成果及找矿实践提出，在太行山中北段应注意寻找拆离滑脱带型金矿。  相似文献