Application of topography fast marching method in landslide     

YANG Junjie  SUN Hui  WEI Chengwu  JIANG Zhenghong  LI Meng 《世界地质(英文版)》2021,24(3):160-168

Geophysical exploration methods are important tools for landslide disaster assessment, landslide treatment scheme design, and landslide prevention engineering. Seismic exploration, as an important geophysical exploration method, plays an critical role in geological disaster evaluation. Traveltime is one of the most frequently used seismic attributes. Among many different traveltime calculation methods, the fast marching method(FMM) is featured for its advantages in high efficiency, high accuracy and strong stability. In this paper, the velocity models are established according to the real landslide models, and then the topography FMM is applied to these landslide models. The calculation results show that topography FMM outperforms in calculating the traveltime for landslides.  相似文献   

大洋有孔虫中硼同位素研究与大气pCO2的重建     

倪云燕  刘嘉麒  隋建立 《地学前缘》2007,14(4):204-214

大气二氧化碳浓度(pCO2)的变化在全球气候演化中起着重要的调节作用,重建古大气pCO2的变化历史,有助于预测和研究未来的全球气候变化。大洋有孔虫中的硼同位素比值能够反映海水酸碱度的变化,从而为重建大气二氧化碳浓度的变化历史提供了一种新的手段。文中首先简要回顾硼同位素的研究现状,利用硼同位素重建大气二氧化碳浓度变化的原理依据,在此基础上,测试分析了西赤道太平洋806孔全新世和末次冰期最盛期Globigerinoides ruber样品中的硼同位素,得到该地区全新世和末次冰期最盛期大气二氧化碳体积分数分别为(276.7±24)×10-6(2s.d.)和(178.4±16)×10-6(2s.d.),与极地冰心记录吻合得很好。大洋有孔虫中的硼同位素是一个非常有潜力的古海水酸碱度替代指标。  相似文献   

Composite Metallogenic Systems in the Weihai Area of Shandong and Evolution of Continental Dynamic Regimes     

SUN Zhongshi WANG Peifu DENG Jun WANG Qingfei WANG Jianping MU Taisheng SUN Li FAN Siqi YE Songqing LIU Zhenghong CUI Shuxue 《《地质学报》英文版》2007,81(2):312-321

Based on 9 sheets of 1：50,000-scale regional geological survey and guided by the theory of metallogenic systems and integrated analyses of the structural and metallogenic features, this paper hereby puts forward the composite metallogenic systems of the Weihai area, Shandong Province, aiming at solving the problems on the origins and ore-controlling structures of the numerous deposits in the area. Its scientific significance is reflected in the following three aspects： （1） The basic features of the composite metallogenic systems can be recognized, which consist of two types： the Proterozoic metamorphic-hydrothermal metallogenic system and the Mesozoic magmatic-hydrothermal metallogenic system （i.e. the Indosinian-early Yanshanian contact metasomatic metallogenic series and the mid-late Yanshanian magmatic-hydrothermal metallogenic series）. The two series display arcuate and NW-right lateral arrangements and a N-S parallel zonal distribution respectively, with the corresponding mineral assemblages being Au＋Ag＋Pb＋Zn, etc.; and Cu＋Mo＋Fe, Au＋Ag＋Cu＋Pb- Zn＋Mo＋Co-Ni＋sulfides＋silicides＋K-feldspar, etc. （2） The composite metallogenic systems may be used to interpret the complicated genetic relations of the deposits. Through analyses of the relations between the three main metallogenic intervals and their corresponding source rock series （the Jingshan and Rongcheng groups; the Wendong super-unit and the early-middle Yanshanian Weideshan super-unit; and the mid-late Yanshanian Weideshan and Laoshan super-units） as well as a case study of the Fanjiabu gold deposit, we have distinguished the consanguinity between the contact metasomatic （skarn-type） metallogenic series and the magmatic-hydrothermal metallogenic series as well as the noncognate superposition between the two and the metamorphic-hydrothermal metallogenic system. （3） The composite metallogenic systems are easily related to the evolution of continental dynamic regimes. The formation of the metamorphic-hydrothermal metallogenic system has undergone transformations of three different types of tectono-dynamic regimes from extension→compression→ shearing; that of the contact metasomatic （skarn-type） metallogenic system from compression→extension→compression; and that of the magmatic-hydrothermal metallogenic system from extension →subductive compression of the Pacific Plate. The evolutions of the three types are all attributed to the opening-closing or divergence-convergence of the paleocontinent, and all their mineralization corresponds to the interval of transformation from the end of convergence to early integration of the Weihai paleocontinent. All these will benefit our deeper study of the dynamics of continental metallogenic processes.  相似文献   

调水调沙对黄河下游溶解铀浓度及入海通量的影响     

于臣青  江雪艳  孟春霞  隋娟娟  刘倩 《海洋学报》2018,40(10):209-219

为研究调水调沙对黄河下游溶解铀浓度及其入海通量的影响,于2014年调水调沙期间在黄河小浪底站及利津站进行了连续同步观测。结果发现,调水调沙期间,小浪底站溶解铀浓度的平均值在调水阶段为（4.28±0.33）μg/L,调沙阶段为（4.19±0.29）μg/L;利津站溶解铀浓度的平均值在调水阶段为（4.55±0.22）μg/L,调沙阶段为（4.87±0.40）μg/L。无论是调水阶段还是调沙阶段,利津站溶解铀浓度的平均值均比小浪底站高,且调沙阶段溶解铀增加量显著高于调水阶段。进一步分析讨论得出调水调沙期间氧化还原条件的变化以及悬浮颗粒物粒径的变化是影响黄河下游溶解铀化学行为的主要因素。2014年调水调沙的运行使得黄河下游利津站的溶解铀入海通量比河流正常输运状态下增加了8.3×102 kg;而2015年在只进行了调水的情况下,从小浪底站到利津站溶解铀通量减少了4.1×103 kg,说明不同模式下的调水调沙对溶解态铀入海通量的影响是不同的。由于在黄河口咸淡水混合带存在着悬浮颗粒物向水体释放溶解铀的现象,根据调水调沙期间悬浮颗粒物的增加量及溶解铀的释放系数估算得到2010年、2012年、2013年、2014年调水调沙期间在河口混合带释放的溶解铀分别为1.57×104 kg、0.739×104 kg、0.690×104 kg和8.25×102 kg,分别占各自年份全年溶解铀入海通量的15%、7.7%、5.3%和1.3%。  相似文献   

Cloning and characterization of proliferating cell nuclear antigen gene of Alexandrium catenella (Dinoflagellate) with respect to cell growth     

HUANG Jian  LIANG Shan  SUI Zhenghong  MAO Yunxiang  GUO Hao 《海洋学报(英文版)》2010,29(3):90-96

Harmful algal blooms (HABs) have been affecting negatively the shellfish and aquaculture industries around the world. Though a lot of efforts have been made to disclose the changes of environmental factors involved and their effects on the HABs events, the molecular mechanism of this process remains unclear. To address this problem, proliferating cell nuclear antigen gene (pcna) was isolated and characterized from Alexandrium catenella. It showed high homology to those of other dinoflagellates (89% and 91% homology to Pfiesteria piscicid and Pyrocystis lunula, respectively), and also 42%-43% homology to those of plant and animals. The expression level of pcna revealed by quantitative real time PCR was the lowest at the late lagging cell growth phase, increased to the highest at the late exponential phase, and then decreased at the stationary phase. Though the cell growth rate was also changing, no positive correlation between pcna expression level and cell growth rate was displayed throughout the whole cell growth stages (r²=0.024 6). However, the pcna expression level had the similar trend with the change of cell growth rate throughout the whole growing process, e.g., from increasing at the earlier cell growth stage to decreasing at the following stages, though slightly lagging to the latter.  相似文献   

安哥拉红砂现场试坑浸水试验研究          下载免费PDF全文

乔建伟  刘争宏  夏玉云  王冉  唐立军 《地震工程学报》2024,(3):521-528

为准确评价安哥拉红砂场地的自重湿陷特征,开展现场试坑浸水试验,对地表及不同深度地层变形、水分入渗规律和浸水前后标贯击数进行监测与研究,并对现场试验与室内试验结果差异性进行探讨。结果表明：浸水后红砂地基表现为持续抬升,变形曲线可分为陡升、缓升、不稳定和趋于稳定4个阶段;深度8 m以上红砂地层为湿陷沉降变形,累计沉降量为5.6 mm,远小于室内试验计算的自重湿陷沉降量137 mm;红砂竖向渗透速率和水平渗透速率均较大,浸水和停水后红砂含水率变化较快,红砂持水性较差,浸水过程中红砂地层的饱和度小于80%,为非饱和渗透;浸水后红砂地层标贯击数显著降低,具有显著的软化特性。红砂较大的渗透系数和较差的持水性导致红砂很难达到饱和状态,是自重湿陷沉降量实测值远小于计算值的因素之一,一般工程建设中建议可不考虑红砂地基的湿陷特性,而将其按软化特性进行设计。研究结果不仅可指导红砂场地未来工程建设,还可为其他砂土湿陷性评价提供借鉴。  相似文献   

华南南华纪武陵锰矿成矿带松桃李家湾-高地-道坨地堑盆地研究新进展和潜力预测     

沈红钱  张遂  曾飞  谢小峰  杨炳南  谢兴友  蔡国荣  沈小庆  朱璞  姚希财  吴应值  杨俊 《贵州地质》2021,38(2):129-138

华南南华纪武陵锰矿成矿带松桃李家湾-高地-道坨地堑盆地控制形成了系列著名的大型-超大型锰矿床.本文依托2020—2021年实施的贵州松桃高地超大型锰矿床大精查(勘探)项目最新成果,运用锰矿气液喷溢沉积成矿理论与隐伏锰矿找矿预测技术体系,对该地堑中的含锰岩系、(富)锰矿体厚度、矿石品位等变化规律及气液喷溢矿石相特征进行综...  相似文献   

黔渝毗邻区杨家湾-老木湾南华纪含锰地堑特征与找矿预测     

沈红钱  张遂  谢小峰  袁良军  杨炳南  朱璞  谢兴友  郑超  张平壹  张仁彪  姚希财 《贵州地质》2021,38(1):1-7

黔渝毗邻区杨家湾-老木湾南华纪含锰地堑系南华裂谷盆地(I级)中的武陵次级裂谷盆地(Ⅱ级)、松桃—古丈次级地堑盆地(Ⅲ级)中的众多Ⅳ级含锰地堑之一.运用锰矿裂谷气液流体喷溢沉积成矿理论与找矿预测模型,对该含锰地堑中的含锰岩系、锰矿体厚度等变化规律进行综合研究,圈定了杨家湾-老木湾IV级含锰地堑的空间分布范围.含锰地堑长轴...  相似文献