Geochemical and C, O, Sr, and U-series isotopic evidence for the meteoric origin of calcrete at Solitario Wash, Crater Flat, Nevada, USA     

L. A. Neymark  J. B. Paces  B. D. Marshall  Z. E. Peterman  J. F. Whelan 《Environmental Geology》2005,48(4-5):450-465

Calcite-rich soils (calcrete) in alluvium and colluvium at Solitario Wash, Crater Flat, Nevada, USA, contain pedogenic calcite and opaline silica similar to soils present elsewhere in the semi-arid southwestern United States. Nevertheless, a ground-water discharge origin for the Solitario Wash soil deposits was proposed in a series of publications proposing elevation-dependent variations of carbon and oxygen isotopes in calcrete samples. Discharge of ground water in the past would raise the possibility of future flooding in the unsaturated zone at Yucca Mountain, Nevada, site of a proposed high-level nuclear waste repository. New geochemical and carbon, oxygen, strontium, and uranium-series isotopic data disprove the presence of systematic elevation-isotopic composition relations, which are the main justification given for a proposed ground-water discharge origin of the calcrete deposits at Solitario Wash. Values of δ¹³C (−4.1 to −7.8 per mil [‰]), δ¹⁸O (23.8–17.2‰), ⁸⁷Sr/⁸⁶Sr (0.71270–0.71146), and initial ²³⁴U/²³⁸U activity ratios of about 1.6 in the new calcrete samples are within ranges previously observed in pedogenic carbonate deposits at Yucca Mountain and are incompatible with a ground-water origin for the calcrete. Variations in carbon and oxygen isotopes in Solitario Wash calcrete likely are caused by pedogenic deposition from meteoric water under varying Quaternary climatic conditions over hundreds of thousands of years.  相似文献   

SEDIMENTARY PATTERN OF PROTOTYPE BASIN IN THE DEPOSITION PERIOD OF LAIYANG FORMATION AND THE ADVANTAGEOUS AREAS FOR OIL AND GAS EXPLORATION OF JIAOLAI BASIN   总被引：3，自引：0，他引：3  

WU Zhiping*  LI Ling  LI Wei  ZHOU Yaoqi 《大地构造与成矿学(英文版)》2004,28(2):142-156

1 Introduction As a Mesozoic relict terrestrial basin controlled and reformed by fracture activities in themiddle to late stage in Mesozoic, Jiaolai basin is situated in the middle of the Ludong uplift, beingoverthrusted upon Jiaobei uplift in the north, adjoining Jiaonan uplift in the south atWulian-Rongcheng fracture, being connected to Tanlu fracture belt in the west, with its NE partextending into the Yellow Sea and connecting to Qianliyan uplift at Qianliyan fracture. Due totec…  相似文献   

Geochemical Constraints of Sediments on the Provenance, Depositional Environment and Tectonic Setting of the Songliao Prototype Basin   总被引：1，自引：0，他引：1  

YAN Quanren  GAO Shanling  WANG Zongqi  LI Jiliang  XIAO Wenjiao  HOU Quanling  YAN Zhen  CHEN HaihongInstitute of Geology & Geophysics  Chinese Academy of Science  Beijing Institute of Geology  Chinese Academy of Geological Sciences  Beijing 《《地质学报》英文版》2002,76(4):455-462

The geochemistry of sediments is primarily controlled by their provenances, and different tectonic settings have distinctive provenance characteristics and sedimentary processes. So, it is possible to discriminate provenances, depositional environments and tectonic settings in the development of a sedimentary basin with the geochemistry of the clastic rocks. The analytical results of the present paper demonstrate that sediments in the Songliao prototype basin are enriched in silica (SiO2=66.48-80.51 %), and their ΣREE are 30-130 dmes of that of chondrite with remarkable Eu anomalies. In discriminating diagrams of Eu/Eu vs eeeeeREE and (La/Yb)N vs ΣREE, most samples locate above the line Eu/ Eu=l, on the right of the line Eu/Eu/ΣREE=1 and under the line La/Yb)N/eeeeeREE=1/8, which indicates that the depositional environment of sediments in the basin was oxidizing. In addition, variations of MgO, TiO2, A12O3, FeO+Fe2O3, Na2O and CaO vs SiO2 reflect a tendency of increasing mineral maturity of sediments  相似文献   

综合地球物理方法在高放废物处置场址特性评价中的应用     

程纪星  伍岳  韩绍阳  姜义生  侯惠群 《铀矿地质》2002,18(3):174-179

本介绍了地球物理方法在我国高放废物处置库场址特性评价中的作用，即查明研究区内断裂的位置，宽度，倾向，倾角及其含水性和确定预选区内花岗岩底板的埋深，此项研究成果显示了该方法在我国干旱地区的深部地质环境及水资源分布研究中的有利应用前景。  相似文献   

地方性知识与空间治理——以苏州东山内圩治理为例   总被引：1，自引：0，他引：1  

周尚意  苏娴  陈海明 《地理研究》2019,38(6):1333-1342

太湖流域水环境综合治理既是一项环境治理任务,也是一项空间治理工程,它涉及太湖沿岸土地利用方式的改变。以人类学家吉尔兹关于局外人对局内人地方性知识的语义理解为学术对话观点,以苏州东山内圩地区为研究区域,采用访谈法、资料分析法、对比法,寻找规划专家的科学知识与当地养殖户地方性知识的语义“原型”。研究发现：① “长度”是“合理规划养殖水塘”的语义“原型”。语义“原型”的发掘使专家在设计空间治理指标时,可采纳养殖户的地方性知识,也为养殖户理解空间治理指标、更新其地方性知识提供可能性。② 地方性知识不单由当地人创造,还在内外两类人群的互动中不断更新。在该过程中,准局外人发挥着知识对接的桥梁作用。当地人的地方性知识没有考虑宏观区域的可持续发展,而专家的全局视野会帮助当地人改进地方性知识。  相似文献   

羌塘盆地晚三叠世原型盆地性质探讨   总被引：16，自引：1，他引：15  

高春文贾庆军  魏春光 《地质论评》2006,52(2):198-206

通过系统地对羌塘地区晚三叠世盆地的区域构造格架、岩石大地构造及沉积建造研究,对晚三叠世盆地的原型盆地性质进行探讨。认为该区晚三叠世盆地形成于新特提斯分支洋盆孕育阶段,岩浆岩地球化学特征显示为板内拉张环境,盆地中央隆起和南北凹陷形成于不同的地质时期。多数地质事实不支持前人比较公认的该盆地为前陆盆地的观点。将该区晚三叠世盆地的盆地性质确定为准克拉通盆地。  相似文献   

关于建立地理信息术语库的思考     

朱秀丽  LI Li  王强 《地理信息世界》2008,6(2):17-22

地理信息与其他学科交叉、渗透,迅速发展,产生了大量新的术语,如何构建地理信息术语库,是地理信息发展了多年后应考虑的问题.文中在分析地理信息术语现状和特点的基础上,提出建立易于检索、网上注册术语库,是实现实时注册维护地理信息术语的基础,本文也对地理信息术语库建设中标准化的问题进行了阐述.  相似文献   

塑料排水带地基处理研究   总被引：2，自引：0，他引：2  

李富强  王钊  刘华清 《岩土力学》2006,27(11):2056-2060

在濒海某场地的塑料排水带地基固结试验中,进行了孔隙水压力、沉降量、侧向位移等原型观测,并按沉降计算固结系数和固结度。固结结束后,用静力触探、十字板剪切仪、标准贯入和平板载荷试验检测处理效果。结果表明：排水带在很短的时间（50 d内）使加固的地基达到固结稳定,说明在濒海软土地区采用排水带固结是有效的加固手段。  相似文献   

面向共享的空间元数据管理框架研究与设计   总被引：12，自引：0，他引：12  

王继周  李成名  林宗坚 《国土资源遥感》2003,14(3):67-70

在空间数据应用范围日益拓宽的同时,空间元数据的共享问题成为限制其发展的主要瓶颈之一。本文分析了目前我国空间元数据管理中存在的问题,列举了两种可行的空间元数据共享策略及相应的国际标准,探讨了面向共享的空间元数据的管理框架。  相似文献   

Global and local sensitivity analyses for coupled thermo–hydro–mechanical problems          下载免费PDF全文

Long Nguyen‐Tuan  Tom Lahmer  Maria Datcheva  Tom Schanz 《国际地质力学数值与分析法杂志》2017,41(5):707-720

This paper focuses on the sensitivity analysis for coupled thermo–hydro–mechanical problems employing both local and global sensitivity methods. A derivative‐based method is used in the local sensitivity approach, whereas the random balance designs method is used for the global sensitivity analysis. The main goal is to investigate the effect of uncertainties in the constitutive parameters on the results from nonlinear coupled thermo–hydro–mechanical analyses of unsaturated soil behavior whose modeling generally involves large sets of constitutive relations. Knowing the parameter sensitivity allows to qualitatively assess the validity of the results obtained by computational simulations of high‐risk situations, for example, emerging nuclear waste repositories. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献