Simulation of less‐mobile porosity dynamics in contrasting sediment water interface porous media          下载免费PDF全文

Farzaneh MahmoodPoor Dehkordy  Martin A. Briggs  Frederick D. Day‐Lewis  Amvrossios C. Bagtzoglou 《水文研究》2018,32(13):2030-2043

Considering heterogeneity in porous media pore size and connectivity is essential to predicting reactive solute transport across interfaces. However, exchange with less‐mobile porosity is rarely considered in surface water/groundwater recharge studies. Previous research indicates that a combination of pore‐fluid sampling and geoelectrical measurements can be used to quantify less‐mobile porosity exchange dynamics using the time‐varying relation between fluid and bulk electrical conductivity. For this study, we use macro‐scale (10 s of cm) advection–dispersion solute transport models linked with electrical conduction in COMSOL Multiphysics to explore less‐mobile porosity dynamics in two different types of observed sediment water interface porous media. Modeled sediment textures contrast from strongly layered streambed deposits to poorly sorted lakebed sands and cobbles. During simulated ionic tracer perturbations, a lag between fluid and bulk electrical conductivity, and the resultant hysteresis, is observed for all simulations indicating differential loading of pore spaces with tracer. Less‐mobile exchange parameters are determined graphically from these tracer time series data without the need for inverse numerical model simulation. In both sediment types, effective less‐mobile porosity exchange parameters are variable in response to changes in flow direction and fluid flux. These observed flow‐dependent effects directly impact local less‐mobile residence times and associated contact time for biogeochemical reaction. The simulations indicate that for the sediment textures explored here, less‐mobile porosity exchange is dominated by variable rates of advection through the domain, rather than diffusion of solute, for typical low‐to‐moderate rate (approximately 3–40 cm/day) hyporheic fluid fluxes. Overall, our model‐based results show that less‐mobile porosity may be expected in a range of natural hyporheic sediments and that changes in flowpath orientation and magnitude will impact less‐mobile exchange parameters. These temporal dynamics can be assessed with the geoelectrical experimental tracer method applied at laboratory and field scales.  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   

第21届IUGG大会简介（IAG部份）     

赖锡安  徐菊生 《大地测量与地球动力学》1995,(4)

简要介绍了第２１届国际大地测量与地球物理大会概况和部分专题报告，并着重介绍了ＩＡＧ（国际大地测量协会）组织的学术报告内容以及近年来国际上大地测量学科的新发展。  相似文献   

雪峰古陆地区深部地质构造探讨     

范小林  陆国新  蒋洪堪  江兴歌 《地球科学与环境学报》1994,(1)

笔者收集区内已有的深部物探成果，辅以野外（区域）地质资料，建立地质－地球物理模型，由布格重力异常曲线与其进行人机交互联合解释，探讨该地区深部地质构造．结果表明：①雪峰地区壳内存在古老异地块，残留古洋壳及隐伏古构造侵位岩脉群；②中新生代板内形变使该地区岩石圈发生缩短作用，在地壳浅部形成非对称扇形构造形变体．  相似文献   

Master of the Obscure—Automated Geostatistical Classification in Presence of Complex Geophysical Processes     

Ute C. Herzfeld 《Mathematical Geosciences》2008,40(5):587-618

The topic of this paper is the retrieval of hidden or secondary information on complex spatial variables from geophysical data. Typical situations of obscured geological or geophysical information are the following: (1) Noise may disturb the signal for a variable for which measurements have been collected. (2) The variable of interest may be obscured by other geophysical processes. (3) The information of interest may formally be captured in a secondary variable, whereas data may have been collected for a primary variable only, that is related to the geophysical process of interest. Examples discussed here include mapping of marine-geologic provinces from bathymetric data, identification of sea-ice properties from snow-depth data, analysis of snow surface data in an Alpine environment and association of deformation types in fast-moving glaciers from airborne video material or satellite imagery. Data types include geophysical profile or trackline data, image data, grid or matrix-type data, and more generally, any two-dimensional or three-dimensional discrete or discretizable data sets. The framework for a solution is geostatistical characterization and classification, which typically involves the following steps: (1) calculation of vario functions (which may be of higher order or residual type, or combinations of both), (2) derivation of classification parameters from vario functions, and (3) characterization, classification or segmentation, depending on the applied problem. In some situations, spatial surface roughness is utilized as an auxiliary variable, for instance, roughness of the seafloor may be derived from bathymetric data and be indicative of geological provinces. The objective of this paper is to present components of the geostatistical classification method in a summarizing and synoptical manner, motivated by applied examples and integrating principal and generalized concepts, such as hyperparameters and parameters that relate to the same physical processes and work for data in oversampled and undersampled situations, parameters that facilitate comparison among different data types, data sets and across scales, variograms and vario functions of higher order, and deterministic and connectionist classification algorithms.  相似文献   

一种表征遥感图像深部层次信息的方法     

陈圣波  周云轩  刘万崧 《遥感学报》2001,5(5):367-369,T005

介绍一种定量地表征遥感地质构造深部层次信息的方法，即利用重磁数据三维欧拉反褶积结果，叠加到遥感图像上，定量地、直接地分辨出遥感构造的深度。并应用到松辽盆地西部斜坡带，效果较好。  相似文献   

中国2000城市地球物理研究战略研讨会简况     

于晟  常旭 《地球物理学进展》2001,16(1):117-119

介绍了在我国首次召开的城市地球物理战略研讨会，城市地球物理学是地球科学研究领域中的新兴学科，随着世界经济建设水平的不断提高，城市化速度加快，人类的生产活动与自然灾害对城市造成的隐患和危害也越来越大。城市化问题使得传统地球物理学的研究方法、研究对象和研究内容面临着机遇和挑战。  相似文献   

深部地球物理探测数据库总库与图形库管理系统建设          下载免费PDF全文

吴仲煜  骆团结 《地球学报》2001,22(6):497-500

深部地球物理探测数据库包括7个专业子库，但由于7个子库均是独立存在，因此无法通过某一个子库了解整个深部地球物理探测数据库的汇总性信息，而且对某些简单信息的查询也必须进入子库才可以完成。建立“总库与图形库管理系统”，就是以7个子库为数据对象，针对管理部门，科研机构和社会公众的不同需求，将数据库技术和GIS相结合，以文本和图形2种方式，实现对整个深部地球物理探测数据库的数据查询和汇总，并把包括7个子库在内的地球物理探测数据库集成为一个系统。  相似文献   

国外勘查地球物理工作现状和发展趋势     

崔霖沛 《地球物理学进展》1992,(4)

概略介绍了国外勘查地球物理工作的现状和某些发展趋势,其中着重介绍利用地球物理方法进行区域地质调查和地壳、上地幔调查、寻找深部隐伏矿床、计算矿产储量和研究环境地质问题.还提到勘查地球物理方法技术的重大进展.在介绍现状的同时,力图指出勘查地球物理的一些新的应用领域、新的方法技术和发展思路.  相似文献   

柴达木盆地德令哈坳陷石炭系分布特征   总被引：1，自引：0，他引：1  

林存国  尹成明  王财富  王占斌  郭术辉  杨大兵  张弘强  吴鹏 《地质通报》2016,35(203):293-301

柴达木盆地具有丰富的油气资源,柴北缘、柴西、柴东三湖地区分别以侏罗系、古近系、新近系和第四系为主要勘探目的层。随着准噶尔盆地石炭系研究的进展和钻探的成功,石炭系已经成为中国西部地区重要的勘探层系。柴达木盆地的石炭系广泛发育,厚度较大,为一套碎屑岩与碳酸盐岩混合岩系,地质调查表明,石炭系为柴达木盆地一套潜在烃源岩。德令哈地区是柴达木盆地石炭系出露最多、地层层序最完整的地区。通过对德令哈及柴东地区MT勘探资料的处理解释和综合研究,对石炭系分布进行了深入研究,认为石炭系分布范围广、厚度大、构造稳定,其中欧龙布鲁克凸起油气成藏条件有利,是勘探的有利目标。  相似文献