兰州-天水地区三维重力反演及其地质解释     

李渭娟  梁桂培  姚政生 《地震工程学报》1993,15(4):45-51

本文利用重力资料对兰州－天水地区的深部构造进行了研究。在计算中，采用Ｐａｒｋｅｒ－Ｏｌｄｅｎｂａｒｇ三维位场反演方法，反演前对重力资料进行了地形改和中新生低沉积层校正。根据反演结构，综合反演结果，综合分析了有关资料，认为该区为青藏块体过渡带，并且并且提出了陇中盆地为断块型构造盆地的新认识。  相似文献   

Assessing the performance of structure‐from‐motion photogrammetry and terrestrial LiDAR for reconstructing soil surface microtopography of naturally vegetated plots          下载免费PDF全文

Sayjro Kossi Nouwakpo  Mark A. Weltz  Kenneth McGwire 《地球表面变化过程与地形》2016,41(3):308-322

Soil microtopography is a property of critical importance in many earth surface processes but is often difficult to quantify. Advances in computer vision technologies have made image‐based three‐dimensional (3D) reconstruction or Structure‐from‐Motion (SfM) available to many scientists as a low cost alternative to laser‐based systems such as terrestrial laser scanning (TLS). While the performance of SfM at acquiring soil surface microtopography has been extensively compared to that of TLS on bare surfaces, little is known about the impact of vegetation on reconstruction performance. This article evaluates the performance of SfM and TLS technologies at reconstructing soil microtopography on 6 m × 2 m erosion plots with vegetation cover ranging from 0% to 77%. Results show that soil surface occlusion by vegetation was more pronounced with TLS compared to SfM, a consequence of the single viewpoint laser scanning strategy adopted in this study. On the bare soil surface, elevation values estimated with SfM were within 5 mm of those from TLS although long distance deformations were observed with the former technology. As vegetation cover increased, agreement between SfM and TLS slightly degraded but was significantly affected beyond 53% of ground cover. Detailed semivariogram analysis on meter‐square‐scale surface patches showed that TLS and SfM surfaces were very similar even on highly vegetated plots but with fine scale details and the dynamic elevation range smoothed out with SfM. Errors in the TLS data were mainly caused by the distance measurement function of the instrument especially at the fringe of occlusion regions where the laser beam intersected foreground and background features simultaneously. From this study, we conclude that a realistic approach to digitizing soil surface microtopography in field conditions can be implemented by combining strengths of the image‐based method (simplicity and effectiveness at reconstructing soil surface under sparse vegetation) with the high accuracy of TLS‐like technologies. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

上海地区第四承压含水层沉积环境及结构特征     

吴建中  俞俊英  李晓  方志雷 《上海国土资源》2009,(1)

上海地区第四承压含水层是地下水开发利用的主要层次,对其沉积环境、成因、结构特征进行深入研究有利于更好地开展地下水资源开发利用及地质环境保护工作.本文在对上海地区大量钻孔资料深入分析的基础上,对第四承压含水层形成时期即早更新世中、晚期沉积环境及含水层的成因进行了深入剖析,对含水层结构特征进行了详细刻画,为三维地质结构的建立奠定了基础.  相似文献   

云南宝兴厂金多金属矿床成矿地质条件     

王绍明  涂国府 《云南地质》2009,28(4):374-379

矿区金、铜、钼矿化与碱性斑岩相关,向阳组碎屑岩是主要矿源层及赋矿地层,北东向响水断裂控矿,近东西向次级断裂及层间断裂为储（容）矿构造。多种条件耦合成矿。  相似文献   

南京下蜀土结构强度研究     

韩爱民  乔春元  丁长阳 《工程地质学报》2009,17(3):371-376

利用常规三轴试验,研究了南京下蜀土结构强度及其影响因素。结果表明,下蜀土存在明显的结构性。当应变小于屈服应变时,土体的结构强度迅速的发挥;当应变大于屈服应变时,土体结构发生破坏,结构强度逐渐降低;最终当各个结构单元重新排列稳定时,土体结构完全被破坏。讨论了围压和含水量对结构强度的影响,结果表明南京下蜀土土体的结构强度和围压无关,和含水量有良好的幂函数关系。结构强度与非饱和土中吸附强度有一定的关系,可以用结构强度代替吸力,从而简化非饱和土抗剪强度公式。   相似文献   

基于结构导向的梯度属性边缘检测技术   总被引：1，自引：1，他引：0       下载免费PDF全文

宋建国  孙永壮  任登振 《地球物理学报》2013,56(10):3561-3571

地震数据中的不连续性检测对于识别和刻画地下地质体边界具有重要意义.随着勘探目标向岩性油藏和复杂断块油藏的转变,解释人员需要对小断裂、微裂缝等微幅地质体边界信息进行精细刻画.常规边缘检测算子由于算法的局限性不能满足上述需求.本文通过引入能量归一化和沿层检测思想对常规检测算子进行改进,提出一种基于结构导向的梯度属性边缘检测技术.该技术通过结构张量估计得到局部地层区域的倾角和方位角,利用得到的倾角和方位角信息作为约束,使用二维边缘检测算子实现三维数据中的沿层不连续性检测.经过实际资料处理,并与结构导向方差属性对比分析,证实该方法在地层不连续性检测方面具有很好效果,检测得到的不连续性信息在细节上表现更丰富,可以作为地层横向差异和地质体边界识别的有力工具.  相似文献   

云南双江白水河金矿成矿地质特征     

张保龙  徐荣  李高良  李小宽  文杰 《云南地质》2012,(3):297-300

白水河金矿属断裂构造控制的热液蚀变型金矿床,金矿体产于新元古界澜沧群变质岩区多期断裂的次级分支断裂破碎带内。沿构造带有辉绿岩脉、石英斑岩脉、煌斑岩脉侵入,首次在临沧地区新元古界澜沧群变质岩区找到金矿。  相似文献   

Molar‐Tooth Structure from the Mesoproterozoic Wumishan Formation in Lingyuan,Yanshan Region,North China,and Geological Implications   总被引：1，自引：0，他引：1  

KUANG Hongwei  LIU Yongqing  PENG Nan  LUO Shunshe  LI Jiahu  CEN Chao  CHEN Mingpei 《《地质学报》英文版》2012,86(1):85-95

Although its origin has not yet reached a consensus so far, MTS (Molar-Tooth Structure) has been documented for more than 100 years. Current study reports a discovery of MTS from the Mesoproterozoic Wumishan Formation, Lingyuan, Yanshan Region, North China, and the features and geological implications of MTS are further discussed. Here, straitigraphic horizons of MTS’s occurrences show that it was mainly located within the top part of the Wumishan Formation, i.e., limestone unit. Four kinds of morphology of MTS, i.e., fine fusiform, debris, ribbon, ptigmatic and nodular (irregular), were recognized and thought to be highly related to the sedimentary environments and facies. Geochemistry of MTS including oxides, trace elements and C, O and Sr isotopes indicates that the horizons of MTS-bearing is of higher Sr/Ba and Ca/Mg ratios, lower positive δ13C and highly negative δ18O values than the adjacent stratigraphic levels of rare MTS. Lithology, morphology and geochemistry of MTS in the Wumishan Formation suggest that MTS occurs mainly in shallow subtidal near the storm wave base, which is typically characterized by warm temperature, oversaturated calcium carbonate seawater and high organic productivity. Furthermore, occasional enrichment of algae bacteria here is more favorable for the calcification of calcium oozes and catalytic for MTS. C isotope composition of the Wumishan Formation and MTS of this study is well correlated with that of the Mesoproterozoic Belt Supergroup, North America and Riphean, Siberia, suggesting that MTS acts as a sedimentary record responding to global changes and is a perfect indicator in Precambrian stratigraphic correlation worldwide.  相似文献   

三维地震勘探技术在新疆沙吉海井田中的应用     

王平  李丽萍  马小平  杨森  汪鸿  张炜 《新疆地质》2012,30(3):355-358

针对沙吉海井田以往未开展过地震勘探,煤层多、局部间距小特点,介绍了研究区主要地震反射波与煤层对应关系.通过对T13、T12、T10、T6反射波研究,采用地震波阻抗反演技术对该区煤层厚度及煤层结构进行解释,查明井田构造形态和主要煤层赋存变化特征,取得了较好地震勘探效果.  相似文献   

反倾巨厚层状岩体地震滑坡特征分析     

卡毛措  陈冉升  吴玮江  刘高 《地震工程学报》2011,33(Z1)

针对汶川大地震中产生的在反倾巨厚层状岩体中滑坡的特征,以甘肃武都寨子崖滑坡为实例,通过详细的野外地质调查,结合滑坡区的工程地质环境和面波测试成果,综合分析反倾巨厚层状岩质边坡中形成滑坡的条件,研究其特征和演化机制。不发育结构面、尤其不发育缓倾坡外结构面时此类边坡不具备产生重力滑坡的条件;此类斜坡在仅有水平地震力时同样不易形成滑坡,双向地震力共同作用时易产生地震滑坡。  相似文献