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讨论了以往区域地球化学调查样品分析质量控制方法的优缺点和新的分析质量控制方法,认为区域地球化学调查样品分析质量控制,除进行实验室内部质量控制外,进行实验室外部质量控制是一种行之有效的方法。 相似文献
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Based upon the present research stratus on Nan Ling granites and in the view of the defferenees in the opinions on the ages and periodic division of Nan Ling granites existing among some research units concerned, a proposal has been snbmitted in the paper, pointing out that it is quite necessary to launch a discussion in the deeper-going way on the problem involving the ages of Nan Ling granites and their periodic division in the journal “GEOCHIMICA”. The main topics expected to be discussed are as follows : (1) The existanec of Hereynian granites and the possibility of the formation of non-orogenic granites; (2) The divisional boundary between Yeushanian and Indonsinian granites and their distributional characteristics; (3) The periodic sub-division of Yenshanian granites and their relatiouship with mineralization ; (4) The division of the ,ages of granites older than the Caledonian period. 相似文献
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中国东北地区是解决东亚大陆构造演化的关键地区,备受众多学者关注。近年来,关于额尔古纳地块基底性质和东界问题一直存在争议。本文对太平林场花岗片麻岩进行了锆石LA-ICP-MS U-Pb测年,锆石年龄主要集中在840~830 Ma、800~780 Ma和730~720 Ma的3个时间段内,可能为新元古代时期的3期岩浆热事件时间。其中21个锆石测点 206Pb/238U 年龄的加权平均值为779±20 Ma(MSWD=8.3),表明原岩在新元古代就已侵位结晶; 1个锆石测点U-Pb同位素年龄为494±10 Ma,Th/U比值为0.06,暗示了锆石应为变质成因,可能为花岗片麻岩的变质年龄。结合前人已报道额尔古纳地块和兴安地块上花岗质岩石年龄数据,对比发现仅额尔古纳地块经历了新元古代岩浆热事件作用; 同时对比两地块上花岗岩Hf同位素特征发现,二者具有不同的地壳早期演化阶段。因此,在早古生代早期二者应该沿塔河-喜桂图缝合带拼合并共同经历了古生代以来的岩浆作用改造,而不是传统观点认为的德尔布干断裂作为两地块的边界。 相似文献
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在以往的一些论著中,把交会角γ=90°时的前方交会和独立三角形称为最佳图形,现在用条件极值来分析此问题,觉得上面的论点并不是可靠的。本文将对此问题作一初步的探讨。 相似文献
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矿床勘探网度原理和控制程度的科学实践 总被引:1,自引:0,他引:1
矿床地质勘探的基本网度,应为矿床(体)的典型地质变量--变化趋势波长的1/2,加密工程间距应为变化趋势波长的“2”的整约数,矿床勘探的控制程度要遵循勘探网度原理,将勘探工程分为总体控制和局部控制,用基本网度进行总体控制,按矿山建设方案对储量和精度的要求部署局部控制,加密控制矿山的首采地段和确定影响开拓的地质问题,为建设设计提供依据,并为开采所利用。矿床地质勘探阶段可用综合制图,网度对比和地质统计分 相似文献
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结合勘测设计企业成本的特点以及勘测设计企业传统成本控制中存在的误区,从成本管理的空间、时间以及手段三个方面对勘测设计企业成本的控制与管理进行了深入的探讨,以期为勘测设计企业的成本控制与管理提供有益的借鉴。 相似文献
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This study combines data from many published case studies to undertake a quantitative characterization of clastic parasequences, with the aim to determine how accommodation, sediment supply and autogenic sediment-storage dynamics are recorded in their sedimentary architecture and stacking patterns. Results of this study are used to critically evaluate the validity of paradigms and models that are routinely used to explain and predict trends in the anatomy and arrangement of parasequences. Data on 957 parasequences from 62 case studies of clastic, shallow-water successions were coded in a relational database, which includes outcrop and subsurface datasets of ancient and Quaternary examples. These units cover the preserved records of both river-dominated deltas and wave-dominated coasts, representing shoreline transits over a breadth of timescales, likely of both local and regional extent. The role of extant accommodation, rates of creation of accommodation and rates of sediment supply in determining parasequence architecture is assessed through analysis of relationships between: (i) proxies of these variables at different scales (rates of aggradation and progradation, facies-belt shoreline trajectories, systems-tract type, parasequence-set stacking patterns, parasequence progradation angle and stratigraphic rise, size of feeder rivers); and (ii) parameters that describe the geometry and stacking style of parasequences, and associated shallow-water sand bodies. Statistical analyses of database outputs indicate which proxies of accommodation, sediment supply and accommodation/sediment-supply ratio are significant as predictors of parasequence architecture, and allow for interpretations of the importance of allogenic and autogenic factors. The principal results of this study reveal the following: (i) parasequence thickness varies as a function of water depth, accommodation generation and erosional truncation, and these variations are also reflected across types of systems tracts and parasequence sets; (ii) the dip length of parasequence sand bodies demonstrates scaling with measures of accommodation/sediment-supply ratio at multiple scales, partly in relation to the possible effect of sediment supply on progradation rates; (iii) in systems tracts, stratigraphic trends in parasequence stacking due to autogenic mechanisms or to acceleration or deceleration in relative sea-level fluctuations are not revealed quantitatively; (iv) some association is seen between the abundance of deltaic or river-dominated parasequences and progradational stacking; (v) positive but modest correlation is observed between measures of river-system size and the dip length of shallow-marine parasequence sand bodies. The resulting insights can be applied to guide sequence stratigraphic interpretations of the rock record and the characterization of sub-seismic stratigraphic architectures of subsurface successions. 相似文献
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论地质灾害防治与地质环境利用 总被引:2,自引:0,他引:2
分析了中国地质灾害防治现状,概述了地质灾害防治体系,以甘肃舟曲“8.8”特大山洪泥石流灾害为例反思了地质灾害防治理念的不足。从地质环境可持续开发利用视角,构建了区域地质环境可持续利用评价框架和地质安全评价体系。基本结论是:应跳出单纯工程地质评价和地质灾害防治的惯性思维,将保护地质环境和防治地质灾害有机结合,树立持续利用地质环境的科学观,更有效地达到减轻地质灾害的目的。 相似文献
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垃圾填埋处理场渗滤液污染地下水的防治途径探讨 总被引:1,自引:0,他引:1
通过分析天水市麦积区老虎沟垃圾填埋处理场地质环境,结合挥发酚(C6H5OH)弥散试验资料,对垃圾处理场渗滤液中C6H5OH的运移特征、污染地下水机理进行了探讨,为垃圾填埋处理场有效防渗提供了设计依据。 相似文献
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合山煤田是典型的岩溶充水矿床.矿井开采水害严重。煤层的直接顶、底板为碳酸盐岩类,岩溶极为发育,为矿井的直接充水含水层;煤层底部的茅口组为强岩溶含水层,与煤系地层的联系密切,为间接充水含水层;位于煤田两侧的红河水是矿井充水最主要的补给水源。断裂、节理和破碎带等通道是矿井充水的主要通道。通过分析井下突水点的发育特征,认为强岩溶导水带是矿井突水的关键部位,防治矿井水害的重点是切断岩溶导水带,对强导水带进行封堵,防止红水河的侧向补给,对四煤底板灰岩进行加固。总结出地面防治的主要方法为帷幕式、截堵式、堵水点式和地面铺盖式。对井下防治水,提出了有疑必探,先探后掘,设置防水闸门、防水墙,实行分层、分区开采,加强井下排水等防治措施。 相似文献
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防洪系统风险分析的研究评述 总被引:13,自引:0,他引:13
以风险的基本概念(风险的定义、特征和风险分析方法)为基础,在排雨水道涵洞设计、堤防河道行洪、水库大坝安全、洪水及风险管理决策等诸方面对防洪系统风险分析的研究进展加以评述,并对其发展进行了展望。 相似文献
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本文着重阐述了市场经济条件下,对建设项目工程造价实施控制的必要性和重要性,并对如何做好该项工作提出了一些看法。 相似文献