POSITIVE INVERSION STRUCTURE OF THE CENTRAL STRUCTURE BELT IN TURPAN-HAMI BASIN

The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall, and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.     

Pathological Microstructure of a Miocene Ostrich Eggshell from Asia

Struthio linxiaensis is the oldest fossil ostrich from Asia till today. This paper analyzes the microstructure of the eggshell of Struthio linxiaensis. The SEM and light microscopic results show that a pathological structure occurred associated with the formation of pore canal. The feature of this structure is that crystals of the columnar layer are around the lower part of the pore canal, and formed a broad structure. This structure unit contracts upwards more severely than the canal and looks like a ＂garlic＂, which was observed in aumiotes eggshells for the first time. Many evidences indicate that this structure was deposited with the columns simultaneously. The radial section view suggests that the ＂garlic structure＂ is not a result of antiperistaltic waves in the avian oviduct. The most possible process of the ＂garlic structure＂ formation is the column units around the pore canals with imperfect acidifying when calcified, or have some correlations with the changes in the protein profiles of the organic matrix in the calcareous eggshell.     

Exposed Cross-section of the Archaean Lower Crustin the Shanxi-Hebei-Inner Mongolia Border Region: Problems and Prospects

The Archaean lower crust represented by granulite facies rocks, which is rare in China, is found to be exposed in the Shanxi-Hebei-Inner Mongolia border region. Studies of the regional structure and deformation and metamorphism of the region indicate that there occurred at least two phases of deformation and metamorphism in the region. Early-phase nearly E-W-directed deformational structure is well preserved in the Zhangjiakou-Xuanhua area. Observations of the features of the geological structure from north to south (in the Hengshan metamorphic terrain) have revealed a possible exposed cross-section through the Archaean lower crust. The structure was superimposed by a NE-SW-trending high-temperature ductile shear zone in the Datong area in the late phase, thus reworking the Archaean sequence.     

Three‐dimensional Evolutionary Models of the Qiongxi Structures,Southwestern Sichuan Basin,China: Evidence from Seismic Interpretation and Geomorphology

Fold terminations are key features in the study of compressional fault-related folds. Such terminations could be due to loss of displacement on the thrust fault or/and forming a lateral or oblique ramp. Thus, high-quality seismic data would help unambiguously define which mechanism should be responsible for the termination of a given fault-related fold. The Qiongxi and Qiongxinan structures in the Sichuan Basin, China are examples of natural fault-propagation folds that possess a northern termination and a structural saddle between them. The folds/fault geometry and along-strike displacement variations are constrained by the industry 3-D seismic volume. We interpret that the plunge of the fold near the northern termination and the structural saddle are due to the loss of displacement along strike. The fault geometry associated with the northern termination changes from a flat-ramp at the crest of the Qiongxinan structure, where displacement is the greatest, to simply a ramp near the northern tip of the Qiongxi structure, without forming a lateral or oblique ramp. In this study, we also use the drainage pattern, embryonic structure preserved in the crest of the Qiongxinan structure and the assumption that displacement along a fault is proportional to the duration of thrusting to propose a model for the lateral propagation of the Qiongxinan and Qiongxi structures. Specifically, we suggest that the structure first initiated as an isolated fault ramp within brittle units. With increased shortening, the fault grows to link with lower detachments in weaker shale units to create a hybridized fault-propagation fold. Our model suggests a possible explanation for the lateral propagation history of the Qiongxinan and Qiongxi structures, and also provides an alternative approach to confirming the activity of the previous Pingluoba structure in the southwestern Sichuan Basin in the late Cenozoic.     

HETEROGENEITY AND WATER SENSITIVITY OF RESERVOIRS OF ZHENG 408 GLUTENITE BODY IN WANGZHUANG OILFIELD, SHANDONG PROVINCE, EAST CHINA

1. IntroductionWangzhuang oilfield is located in Wangzhuang village, Lijin County of Dongying city. In structure, it is in the west of the northern abrupt slope bolt of Dongying sag and lies to the south of Chenjiazhuang arch. It is a complex oilfield of a buried hill oil pool with bedrock of Archaeozoic Erathem and lithology-stratum reservoir of Paleogene System. The structure of this region is simple, high in the north and low in the south. Study object is the upper of Member 3 of Shah…     

Basal Melt-out Structure in the Luoauan Formation and Its Significance

The Late Precambrian Luoquan Formation occurring on the southern margin of the North China platform is of important significance for the study of the tectonics, palaeogeography, palaeoclimatology and regional stratigraphy of the North China and Yangtze platforms. The origin of diamictites of the formation has long been a subject of controversy. Recently a certain type of cross bedding structure has been recognized in the massive diamictite. Analysis of the process of deposition indicates that the structure was formed by the basal melt-out process of the glacier and, to some extent, its form is the manifestation of the primary structure of basal debris-rich glacial ice. The discovery of this sedimentary structure is inducive to the understanding and reconstruction of the features and environmental conditions for the development of the glaciers in the Luoquan Glacial Epoch.     

Progress in the Study of Deep Profiles of Tibet and the Himalayas (INDEPTH)

This paper introduces 8 major discoveries and new understandings with regard to the deep structure and tectonics of the Himalayas and Tibetan Plateau obtained in Project INDEPTH, They are mainly as follows. (1) The upper crust, lower crust and mantle lithosphere beneath the blocks of the plateau form a "sandwich" structure with a relatively rigid-brittle upper crust, a visco-plastic lower crust and a relatively rigid-ductile mantle lithosphere. This structure is completely different from that of monotonous, cold and more rigid oceanic plates. (2) In the process of north-directed collision-compression of the Indian subcontinent, the upper crust was attached to the foreland in the form of a gigantic foreland accretionary wedge. The interior of the accretionary wedge thickened in such tectonic manners as large-scale thrusting, backthrusting and folding, and magmatic masses and partially molten masses participated in the crustal thickening. Between the upper crust and lower crust lies a large detachment (e.g     

New Insights into the Mesozoic Large-scale Intra-plate Magmatism and Mineralization in South China from Seismic Tomography

A great amount of new S-wave data has been combined to image the mantle structure down to lower mantle depth near the southeastern margin of Eurasia and understand the tectonics in South China since the Mesozoic. Our results reveal a large-scale structure beneath the South China Sea, with a prominent, broad low-velocity feature of at least 1500-km wide in and below the mantle transition zone(MTZ) and a pronounced low-velocity feature of nearly 500-km wide in the lowermost mantle. Together these ...     

http://www.sciencedirect.com/science/article/pii/S1674987110000071

<正>The lithospheric structure of China and its adjacent area is very complex and is marked by several prominent characteristics.Firstly,China's continental crust is thick in the west but thins to the east,and thick in the south but thins to the north.Secondly,the continental crust of the Qinghai—Tibet Plateau has an average thickness of 60—65 km with a maximum thickness of 80 km,whereas in eastern China the average thickness is 30—35 km,with a minimum thickness of only 5 km in the center of the South China Sea.The average thickness of continental crust in China is 47.6 km,which greatly exceeds the global average thickness of 39.2 km.Thirdly,as with the crust,the lithosphere of China and its adjacent areas shows a general pattern of thicker in the west and south,and thinner in the east and north.The lithosphere of the Qinghai—Tibet Plateau and northwestern China has an average thickness of 165 km, with a maximum thickness of 180—200 km in the central and eastern parts of the Tarim Basin,Pamir, and Changdu areas.In contrast,the vast areas to the east of the Da Hinggan Ling—Taihang—Wuling Mountains,including the marginal seas,are characterized by lithospheric thicknesses of only 50—85 km.Fourthly,in western China the lithosphere and asthenosphere behave as a "layered structure", reflecting their dynamic background of plate collision and convergence.The lithosphere and asthenosphere in eastern China display a "block mosaic structure",where the lithosphere is thin and the asthenosphere is very thick,a pattern reflecting the consequences of crustal extension and an upsurge of asthenospheric materials.The latter is responsible for a huge low velocity anomaly at a depth of 85—250 km beneath East Asia and the western Pacific Ocean.Finally,in China there is an age structure of "older in the upper layers and younger in the lower layers" between both the upper and lower crusts and between the crust and the lithospheric mantle.     

THRUST NAPPE STRUTRUE IN THE JINGGANG MOUNTAIN：CHARACTERISTICS AND SIGNIFICANCE FOR PROSPECTION OF ORE DEPOSITS

Nappe structure, as was first discovered by the authors during the regional geological survey at the scale of 1:50,000 in The Jinggang Mountain, is mainly comprised of a series of NNE-NE-striking thrust fault zones and thrust sheets among them. Sinian, Cambrian, Ordovician, Devonian, Carboniferous, Triassic, Jurassic and Cretaceous strata are involved in the thrust nappe system. The nappe structure is of the type of duplex structures formed as a result of the earlier stage migration from SE to NW and late stage migration from E to W of sedimentary cover or basement strata. Formation of the nappe structure in the studied area involves two main epochs: Early Yanshanian and Late Yanshanian to Early Himalayan. The mineral deposits and the buried coalfields in the area, especially the latter, are extensively controlled by the nappe structure.     

一种微型桩组合抗滑结构内力分析方法

微型桩组合抗滑结构是指把若干根以一定间距排列的微型桩在顶部用板体连接起来,以抵抗滑坡推力的一种新型支挡加固结构。因其具有桩径小、施工快捷、施工人员安全保障高、经济性好等优点,可用于中小型边（滑）坡的治理工程中,尤其是快速抢险工程。根据此种结构的一般受力特征,在计算桩体内力时,提出把该结构在滑面以上的部分视为在滑坡推力作用下的刚架结构,等效分解后对各桩按弹性地基梁利用m法进行解析,其间考虑了受荷段桩间岩土体对桩的推力作用,各桩体在滑面以下的部分视为弹性桩利用k法进一步计算,于是按照先分析上半部分再计算下半部分的方法可确定出该结构内力。分析结果表明,各微型桩承受轴力、弯矩和剪力,其中轴力作用更为主要。以该类结构在四川省广巴高速公路路堑边坡工程中实际应用为例,通过试验说明了所提算法的合理性。     

岩溶构造对地埋管群换热效率影响数值模拟研究

地埋管是岩体热泵系统与地层直接交换冷热量的部分。岩溶地区含水构造复杂多样,对地埋管群换热储热有明显影响。对27根垂直地埋管群在无岩溶构造、岩溶裂隙构造、岩溶管道构造以及混合岩溶构造4种地质构造类型中的换热过程进行了模拟,并对比了岩体内温度场、埋管出口水温、热泵机组制冷系数(COP)以及单位井深换热量等参数的变化。结果表明:在制冷工况下,不同模型温度场中,岩体中存在岩溶裂隙构造或岩溶管道构造时,地下水流动对岩体热堆积有明显缓解作用;岩溶导水构造与地埋管的距离也是重要影响因素。模型运行到第1个制冷周期末期时,含岩溶裂隙构造岩体和含岩溶管道构造岩体的进出口水温差比混合岩溶构造岩体的分别升高了0.87、4.00 K;无岩溶构造岩体进出口水温差比混合岩溶构造岩体的下降了1.16 K。无岩溶构造岩体、岩溶裂隙构造岩体、岩溶管道构造岩体和混合岩溶构造岩体的COP分别为7.2、7.4、7.8和7.3;单位井深换热量分别为64.1、90.3、130.7和79.1 W/m。研究结果表明,岩溶导水构造明显增强了地埋管群的换热效率,不同的地质构造类型对地埋管换热效率的影响也不一样。      

塔里木盆地库车坳陷中部构造变形样式及分布特征

库车坳陷是塔里木盆地北部一个次级构造单元,受晚新生代陆内造山作用控制,发育典型的挤压冲断构造; 同时,由于古近系和新近系盐层的存在,发育丰富的盐相关构造; 另外,冲断构造各段之间的调节作用还形成了一系列的走滑构造。本文利用最新的2D、3D 地震资料及钻井资料,分析总结了库车坳陷中部的变形样式及分布特征。研究结果表明: 1)根据变形的成因机制,将库车坳陷的构造变形划分为收缩构造、盐构造及走滑构造。2)收缩构造以逆冲断层及褶皱样式为主,盐上构造层可划分为断层相关褶皱和褶皱相关断层,其中断层多在盐层内滑脱。盐下构造层根据断层组合方式可划分为叠瓦状冲断构造、楔形冲断构造及滑脱冲断构造。盐构造可以划分为盐席、盐墙、盐楔入、盐刺穿及盐拱构造。走滑构造在剖面上可见花状构造及不协调变形,平面上则可见雁列褶皱、马尾断层及海豚效应。3)收缩构造及盐构造主要分布于克拉苏构造带及秋里塔格构造带内,自南天山至盆地中心,盐下构造层由叠瓦状冲断构造过渡至滑脱冲断构造,过渡带内则发育楔形冲断构造; 走滑构造集中于坳陷西部的阿瓦特-却勒构造段以及东部的克拉3-东秋8构造段。     

采场内结构体解算及其稳定性计算

采场内结构体的存在对矿块安全回采影响较大,开展其解算方法与稳定性计算方法研究具有重要意义。应用一般块体理论,以采场四周的开拓巷道结构面调查数据为基础,运用GeneralBlock程序初步解算出采场内结构体,分析结构体的真实性,制定真实性分级表。结合3DMine软件,用定义包裹长方体的方法准确刻划结构体的位置,建立简单材料力学模型,计算出固定结构体的最小固定面面积。对于解算出的结构体,在块体可移动性定理和稳定性原理的基础上,运用材料力学、集合等方法,分析矿块回采过程中结构体可移动性,计算结构体稳定性系数。研究成果成功解算出采场内结构体并进行了稳定性分析,对于裂隙岩体加固与采矿工艺优化具有较好的指导意义。     

粤北长江铀矿田控矿构造解析

控矿构造研究是长江铀矿田的薄弱环节,制约了成矿规律的深入探讨和进一步找矿方向.通过对矿田内控矿构造的详细解析,厘定了控矿构造形式,构建了构造控矿模型,探讨了控矿构造的演化,指出了找矿方向.铀矿田内的矿体和矿化带受北北西(近南北)向展布的小型断裂构造控制,具有走向延伸长、倾向延深大、产状比较稳定、局部弧形形态、呈带状成群...     

采场结构体回采可移动性分析

采场范围内存在的结构体严重影响地下矿山安全生产,分析不同回采顺序下采场结构体可移动性具有重要意义。以块体理论为基础,结合空场法开采的采场空间属性,分析了结构体在采场内的一般嵌套模式。运用GeneralBlock程序建立了采场结构体模型,对采场内结构体的类型、体积和位置等元素进行了解构。利用矢量方法分析了不同回采顺序下采场结构体可移动性,并利用力学方法分析了考虑岩桥破坏时的矢量不可动结构体的回采移动性,推导了结构体破坏岩桥移动的条件公式。以铜坑矿锌多金属矿体1#矿块采场为样本,进行了回采可移动性实例分析,结果表明：一端至另一端后退回采时,4个结构体滑动;中间至两端后退回采时,7个结构体滑动,1个结构体破坏岩桥后滑动;上向水平分层回采时,4个结构体滑动,2个结构体掉落。研究成果可为地下矿山裂隙矿岩空场法回采顺序的合理选择及采场安全管理提供技术指导。     

阶梯-深潭结构对沟道稳定性的作用机制

阶梯-深潭结构是山区河流中典型的高效消能结构,以消耗水能、增加阻力的方式提升沟道稳定性。通过水槽试验模拟沟道冲刷,探究阶梯-深潭结构稳定沟道的机制及效果,为山区河流消能减灾和稳定河床提供科学和技术参考。结果表明：阶梯-深潭结构能有效消耗水流能量、抑制泥沙输移和提升水流阻力,从而有效控制河床下切和边坡破坏;在阶梯-深潭结构的作用下,沟道的Darcy-Weisbach系数约增加为无结构条件下的4倍,时均输沙率降低20%～66%,但随着流量的增大,阶梯-深潭稳定沟道的效果降低;阶梯高度与长度比(0.1)相同时,结构提升沟道稳定性的效果接近。阶梯-深潭结构自身的稳定是其稳定沟道的关键条件,实际应用过程中需防止结构发生逐级破坏。     

渤海湾盆地黄骅坳陷新生代结构特征及构造动力学模式

为了揭示黄骅坳陷新生代构造动力学机制, 本文运用油区构造解析理论, 对黄骅坳陷新生代盆地结构特征做了综合分析。结果表明黄骅坳陷的古近系可视为发育在沧东断层上盘的地堑—地垒构造系统。不同区段的盆地结构特征有显著的差异, 南区总体表现为两个地堑式断陷, 断陷结构与基底断裂产状的变化有关; 中区南部表现为由3条SE向倾斜的正断层控制的半地堑系, 向北变为地堑断陷结构; 北区盆地结构主要受NE向和NW向断层控制, 表现为半地堑或地堑断陷结构。在黄骅坳陷新生代盆地结构特征分析的基础上, 进一步讨论盆地结构演化过程和动力机制之间的关系, 提出了黄骅坳陷新生代构造动力学模式。     

黄土初始结构性对其压缩屈服的影响

黄土是一种典型的具有结构强度的欠压密土,其特殊的结构性会使黄土的压缩曲线出现类似超固结土的明显转折点（对应的压力称为结构压缩屈服应力）。为分析黄土的初始结构性对其压缩屈服的影响,对6个场地的黄土进行了侧限压缩试验及单轴抗压强度试验,分别得到了各个场地不同含水率黄土的压缩屈服应力和构度指标。研究表明：黄土的构度指标与压缩屈服应力均随含水率的增大而减小,同时随含水率的增大,构度变化幅度小的黄土,其压缩屈服应力变化幅度也小;沉积时代相同的黄土,构度越大,其压缩屈服应力越大,两者呈线性关系;黄土的沉积时代不同,其构度与压缩屈服应力的线性关系就不同。分别给出了Q3、Q2黄土的构度与压缩屈服应力的线性关系式,并通过实例初步验证了此线性关系的适用性,为以构度为桥梁,利用简便易得的物理指标计算压缩屈服应力提供了一种途径。