鄂东黄石地区下三叠统大冶组风暴沉积   总被引：4，自引：3，他引：1  

杨宝忠  杨坤光  夏文臣 《古地理学报》2007,9(4):379-386

鄂东黄石地区下三叠统大冶组灰岩中发育了典型的风暴沉积,风暴岩由砾屑灰岩、颗粒灰岩和泥灰岩组成,其中风暴沉积构造包括丘状交错层理、递变层理、砾屑的撕裂构造及水平层理等,不同层位具有不同的风暴沉积构造类型和组合特征。根据风暴沉积的岩石特征、构造类型、规模、组合特点,并结合沉积背景分析,风暴沉积序列可进一步分为深水远源型、过渡型和浅水近源型。大冶组一段风暴沉积具有深水远源特点,沉积环境为水体较深的外陆棚; 大冶组二段风暴沉积具有过渡型特点,沉积环境为向上变浅的内陆棚; 大冶组三、四段风暴沉积具有浅水近源特点,沉积环境为浅水陆棚至滨岸。大冶组沉积序列具有向上变浅的特点,沉积环境由深水陆棚逐渐向滨岸转变。风暴沉积的识别对重建鄂东黄石地区早三叠世古地理具有重要意义。  相似文献   

三维地震方差体微机软件开发及解释技术研究     

李刚  ;杨战宁  ;王玉娇  ;崔瀛潇 《中国煤炭地质》2009,(7):53-56

针对常规三维地震对小断层、陷落柱解释精度较低的现状,提出了三维数据体方差体计算方法,以克服常规解释方法存在的问题。方差体技术的核心,就是求取整个三维地震数据体中所有样点的方差值。方差值参数的选取原则：一是要根据预测的断层走向选择加法模式或乘法模式;二是要根据所预测断层的大小来确定参与运算的道数;三是根据地层倾角的大小选择计算时窗。依据其计算方法及参数选取原则编制了三维地震方差体微机计算软件,利用该软件对山东某区三维地震资料进行了解释。实例表明经方差体计算的水平切片可以很清楚的看断层的错断、同相轴的扭曲及断层的延展方向,经方差体计算的顺层切片对断层的空间展布、走向及相互间切割关系也一目了然,特别是在常规解释结果中却没有明显的反映的较小断层,在顺层切片中清晰可见,由此看见方差体解释技术对断层细节的反映更为清晰。  相似文献   

宁夏中奥陶统香山群徐家圈组内波和内潮汐沉积^*   总被引：5，自引：0，他引：5       下载免费PDF全文

李向东  何幼斌  王丹  高振中  郑昭昌 《古地理学报》2009,11(5):513-523

宁夏中奥陶统香山群为一套遭受轻微区域变质的陆源碎屑岩,并夹有少量碳酸盐岩和硅质岩,主要为深水浊流沉积。其中,徐家圈组主要由灰绿色、黄绿色轻变质细砂岩、钙质砂岩及粉砂岩和页岩组成,顶部发育有薄层石灰岩。在该组的中—薄层钙质粉—细砂岩、细粉屑质石灰岩和粉砂质页岩中发现了双向交错层理及纹层倾向与区域斜坡倾向相反或有较大夹角的单向交错层理,其中双向交错层理形态丰富、纹层清晰,其纹层倾向有沿斜坡向上的,有沿斜坡向下的。在深水环境中,这些交错层理不应是等深流沉积或浊流沉积的产物,而应为内波产生的沿斜坡上下水流交替流动所形成的。从沉积背景、沉积构造和古水流等方面对徐家圈组的内波、内潮汐沉积进行了详细的研究,认为其形成于水道不发育的深水斜坡环境,并对斜坡环境中内波、内潮汐沉积中不发育脉状、波状和透镜状层理的现象进行了解释。  相似文献   

基于弹性理论的顺层边坡失稳破坏力学模型分析   总被引：4，自引：1，他引：3  

李维光  张继春 《工程地质学报》2005,13(2):218-221

在分析顺层边坡受力状况的基础上,当边坡的坡脚未被破坏时,将顺层边坡视为弹性地基上的悬臂梁,由此提出其失稳破坏的力学模型。应用弹性理论求出在力作用下悬臂梁的应力状态,并根据摩尔-库伦准则,导出可判定其稳定性的安全系数计算公式,得出了顺层边坡处于极限平衡状态极限长度。同时通过实例计算,将文中方法与应用突变理论所得结果对比,验证了本文方法的可行性。  相似文献   

Gas flow in anisotropic claystone: modelling triaxial experiments     

D. Arnedo  E. E. Alonso  S. Olivella 《国际地质力学数值与分析法杂志》2013,37(14):2239-2256

Selected gas pulse tests on initially saturated claystone samples under isotropic confinement pressure are simulated using a 3D thermo‐hydro‐mechanical code. The constitutive model considers the hydro‐mechanical anisotropy of argillaceous rocks. A cross‐anisotropic linear elastic law is adopted for the mechanical behaviour. Elements for a proper modelling of gas flow along preferential paths include an embedded fracture permeability model. Rock permeability and its retention curve depend on strains through a fracture aperture. The hydraulic and mechanical behaviours have a common anisotropic structure. Small‐scale heterogeneity is considered to enhance the initiation of flow through preferential paths, following the direction of the bedding planes. The numerical simulations were performed considering two different bedding orientations, parallel and normal to the imposed flow in the test. Simulations are in agreement with recorded upstream and downstream pressures in the tests. The evolution of fluid pressures, degree of saturation, element permeability and stress paths are presented for each case analysed. This information provides a good insight into the mechanisms of gas transport. Different flow patterns are obtained depending on bedding orientation, and the results provide an explanation for the results obtained in the tests. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

基于纳米压痕和FE-SEM技术探究页岩页理结构对其微—宏观力学行为的影响     

解馨慧  邓虎成  胡蓝霄  何建华  李瑞雪  毛金盺  李柏洋 《地质论评》2024,70(S1):319-322

  相似文献   

吉林省中生代陆相风暴岩的观察   总被引：1，自引：0，他引：1  

张普林 《吉林地质》1991,10(2):66-71

于通化三棵榆树等盆地发现的中生代陆相风暴岩具有较为典型的滞留层、风暴冲刷面、渠模、水平层理和丘状层理。根据实际观察初步建立了该风暴岩沉积相序。  相似文献   

清江盆地沉积构造分类及其特征分析     

杨吉根 《华东地质学院学报》1988,(3)

本文提出了我国东南地区中新生代的清江盆地沉积构造的分类,分析了该盆地沉积构造的特征、形成条件和沉积环境,并指出了某些沉积构造为同类型含盐盆地所特有。  相似文献   

Simulating the role of tides and sediment characteristics on tidal flat sorting and bedding dynamics     

Zeng Zhou  Qian Liu  Daidu Fan  Giovanni Coco  Zheng Gong  Iris Möller  Fan Xu  Ian Townend  Changkuan Zhang 《地球表面变化过程与地形》2021,46(11):2163-2176

Understanding sediment sorting and bedding dynamics has high value to unravelling the mechanisms underlying geomorphological, geological, ecological and environmental imprints of tidal wetlands and hence to predicting their future changes. Using the Nanhui tidal flat on the Changjiang (Yangtze) Delta, China, as a reference site, this study establishes a schematized morphodynamic model coupling flow, sediment dynamics and bed level change to explore the processes that govern sediment sorting and bedding phenomena. Model results indicate an overall agreement with field data in terms of tidal current velocities, suspended sediment concentrations (SSCs), deposition thicknesses and sedimentary structures. Depending on the variation of tidal current strength, sand-dominated layers (SDLs) and mud-dominated layers (MDLs) tend to form during spring and neap tides, respectively. Thinner tidal couplets are developed during daily scale flood–ebb variations. A larger tidal level variation during a spring–neap tidal cycle, associated with a stronger tidal current variation, favours the formation of SDLs and tidal couplets. A larger boundary sediment supply generally promotes the formation of tidal bedding, though the bedding detail is partially dependent on the SSC composition of different sediment types. Sediment properties, including for example grain size and settling velocity, are also found to influence sediment sorting and bedding characteristics. In particular, finer and coarser sediment respond differently to spring and neap tides. During neap tides, relatively small flow velocities favour the deposition of finer sediment, with limited coarser sediment being transported to the upper tidal flat because of the larger settling velocity. During spring tides, larger flow velocities transport more coarser sediment to the upper tidal flat, accounting for distinct lamination formation. Model results are qualitatively consistent with field observations, but the role of waves, biological processes and alongshore currents needs to be included in further studies to establish a more complete understanding.  相似文献   

顺倾层状碎裂结构岩质边坡地震动力响应及破坏模式分析     

许明  余小越  赵元平  胡家驹  张潇婷 《岩土力学》2023,(2):362-372

顺倾层状边坡沿软弱带剪切方式破坏是滑坡的主要类型之一。采用块体砌筑斜坡振动台模型,在多维多参数地震动作用下,考虑斜坡不同工况下力学参数弱化的过程,研究了层状碎裂结构岩质边坡的地震动力响应和失稳破坏模式。结果表明：斜坡地震动特性和斜坡地质结构是决定斜坡地震动力稳定性以及破坏模式的决定因素;斜坡水平动力响应具有明显的高程和坡表放大效应,高程对斜坡的垂直动力响应影响较小,地震动放大效应与结构面力学强度、地震波波形、频谱特性等均有一定的关系,正弦波较天然波对坡体放大效应影响更为显著;坡体裂纹依托优势结构面在最弱部位起裂萌生扩展,并向节理面追踪形成蠕滑段和锁固段,节理面强度参数在外界地质营力作用下发生弱化,使潜在滑带出现由后缘向前端搭接贯通的前进式破坏模式和由前端向后缘的后退式破坏模式的分化,滑体也由高位剪出向溃散破坏演变。  相似文献