新疆东天山土墩基性-超基性杂岩体橄榄石成分特征及其成因意义          下载免费PDF全文

王敏芳  夏庆霖  肖凡 郭晓南王 伟刘 坤 《中国地质》2014,41(5):1452-1463

橄榄石通常是玄武质岩浆最早结晶出的矿物之一,其化学成分可以很好地反演母岩浆成分、岩浆结晶分异、硫化物熔离等成岩及成矿信息。本文以土墩镁铁质-超镁铁质杂岩体为研究对象,采用电子探针对岩体中的橄榄石矿物颗粒进行化学成分测试。利用橄榄石的Fo值和其中Ni含量,计算得到土墩杂岩体母岩浆中Mg O含量约为12.95%,是一种富镁的玄武质岩浆。同时,定量模拟结果表明,土墩杂岩体母岩浆中硫化物熔离几乎与橄榄石结晶作用同时进行,早阶段由橄榄石结晶(分离结晶程度约2%)而导致硫化物的熔离程度为0.2%。随后,橄榄石分离结晶程度在6%~7%时,硫化物熔体的熔离程度仅为0.01%。这些表明土墩杂岩体发生过一定程度的硫化物熔离,但成矿前景不是很好。此外,部分数据显示出Ni-Fo的负相关性,表明少许富铁橄榄石和晶间硫化物熔浆发生了Fe-Ni物质交换反应,这对橄榄石的成分有重要影响。  相似文献   

Logging Response Characteristics for Pore Brine Potassium Reservoir in the West of Qaidam Basin     

LI Hongpu  ZHENG Mianping  LIU Ying 《《地质学报》英文版》2014,88(Z1):220-221

正Pore brine potassium and deep sand gravel layer found is of large size and high economic value liquid potash deposit in western Qaidam basin depression tectonic(Fig.1).Because the reservoir is relatively thick,it is difficult to  相似文献   

废弃地下人防洞处理分析     

王荣杰 《岩土工程技术》2014,28(6):308-310

针对废弃人防洞及其对建筑物安全的危害,介绍了压力注浆处理人防洞的原理、方法、工艺、材料、检测方法、处理效果。针对具体实例,介绍了该方法的优点,说明了处理施工的整个过程和工序安排,对今后处理人防洞的实际施工具有一定的借鉴意义。  相似文献   

地下水污染源识别的数学方法研究进展   总被引：3，自引：0，他引：3       下载免费PDF全文

王景瑞  胡立堂 《水科学进展》2017,28(6):943-952

地下水污染源识别模型可利用有限的观测资料估计污染源位置、污染物泄露强度及其泄露过程,是制定地下水污染修复方案的依据。在阐明地下水污染源识别基本问题基础上,综述了污染源识别研究的两大类数学方法,一类为直接方法,包括反向追踪法和基于正则化的方法;另一类为间接方法,包括基于优化的方法和基于概率统计的方法。同时指出了当前污染源识别数学方法应用中存在的主要问题:地下水污染源识别问题的复杂性、地下水有机污染问题和模型求解效率的低下性。对土壤-地下水的联合管理、基于物联网的地下水污染监测、对非水相流体（Non-aqueous Phase Liquid,NAPL）类污染源识别以及基于图形处理器（GPU）的异构并行计算将是未来研究的重点方向。  相似文献   

基于集合卡尔曼滤波的多相流模型参数估计——以室内二维砂箱中重质非水相污染物入渗为例     

康学远  施小清  史良胜  吴吉春 《吉林大学学报(地球科学版)》2017,47(3)

重质非水相有机污染物(DNAPL)泄漏到地下后,其运移与分布特征受渗透率非均质性影响显著。为刻画DNAPL污染源区结构特征,需进行参数估计以描述水文地质参数的非均质性。本研究构建了基于集合卡尔曼滤波方法(EnKF)与多相流运移模型的同化方案,通过融合DNAPL饱和度观测数据推估非均质介质渗透率空间分布。通过二维砂箱实际与理想算例,验证了同化方法的推估效果,并探讨了不同因素对同化的影响。研究结果表明:基于EnKF方法同化饱和度观测资料可有效地推估非均质渗透率场;参数推估精度随观测时空密度的增大而提高;观测点位置分布对同化效果有所影响,布置在污染集中区域的观测数据对于参数估计具有较高的数据价值。  相似文献   

Mathematical modeling of soil mixture flow surge and its application to coastal area     

S. D. Kim  Hojin Lee 《Marine Georesources & Geotechnology》2017,35(5):610-620

The purpose of this study is to investigate debris flow surge that is set up with a numerical model using governing equations applied by the dynamics of a liquid–solid mixture. This model is performed by applying the finite difference method to display elapses of time. To measure the behavior mechanisms of the debris flow surge, the following are analyzed: the flow discharge, flow depth, and sediment volume concentration at the end of downstream channel. The flow discharge and flow depth only surge right after the debris flow reaches the downstream channel as the berm width shortens. In contrast, as the berm width lengthens, the flow discharge and water flow recede. As the berm width decreases, the sediment concentration shows a high concentration and a great height difference at the inflection point. Vice versa, when the berm width increases, an inflection point can be seen, but it reveals a low concentration and a low height difference. The numerical model of this study was applied to the coast of South Korea and analyzed. This study will provide information in predicting disasters caused by debris flow and in planning for various counter measures to prevent disasters.  相似文献   

Ein Vorschlag zur Erzielung hochreflektierender Teleskop-Optik     

T. H. Schmidt-Kaler 《Astronomische Nachrichten》1994,315(4):323-328

Since 60 years the common method generally used to coat astronomical mirrors is vacuum deposition of pure aluminium by evaporation. Such mirror surfaces degrade very fast resulting in a considerably reduced optical throughput. Protecting layers (oxides like SiO₂, fluorides like CaF₂) are not applied because their removal, necessary before realuminization, involves damage to the optical surface of the mirror substrate which would necessitate a costly refiguring of that surface. The reduction of the throughput exceeds typically 30 % for a Cassegrain system; it precludes the introduction of excellent optical design solutions in astronomy based on Schwarzschild's theory using four-reflection optics. In addition, the cost of the conventional procedure of aluminizing and its risks increase tremendously with the size of the mirrors of the very large telescopes now planned or under construction. Here I propose a three-layer composion in two forms (Fig. 1): a) stopping layer -- reflecting layer - protecting layer, or b) carrier layer - protecting layer. The stopping layer is supposed to be completely insensitive to the chemical agents dissolving or detaching the protecting (and the reflecting) layers. On the other hand, in modification b), the carrier layer is supposed to be chemically removable from the substrate, thereby detaching also the protecting (and reflecting) layer. As an example for a layer system of type a) experiments are under way with the system gold/silver/quartz on various mirror substrate materials. Quartz can be easily dissolved by fluorid acid without any damage to the gold stopping layer. Dense. pore free Al₂O₃+SiO₂ layers without defects can be expected to protect the silver reflectance R⩾ 0.98 under real observatory conditions effectively for more than 10-20 years. In addition this protecting layer permits frequent and effective cleaning of the mirror from dust etc. The reflectance of silver exceeds that of fresh conventionally aluminized mirrors with R ≅ 0.87 for all wavelengths λ ⩾ 3370 Å. In the blue the silver mirror realizes with R = 0.995 ideal conditions for Schwarzschild optics. In the V-IR region it is with ≅ 0.99 by the factor 1.2 better than present-day mirrors.  相似文献   

Chronology of Early to Mid-Pleistocene sediments in the northern North Sea: New evidence from amino acid and strontium isotope analyses     

《Quaternary Geochronology》2022

Sediments deposited during glacial-interglacial cycles through the Early to Mid-Pleistocene in the North Sea are chronologically poorly constrained. To contribute to the chronology of these units, amino acid racemization (AAR) and strontium (Sr) isotope analyses have been performed on samples from four shallow borings and one oil well along a transect in the northern North Sea. D/L Asp (aspartic acid) values obtained through reverse-phase liquid chromatography in the benthic foraminiferal species Elphidium excavatum is focused on because of consistent results and a good stratigraphic distribution of this benthic species. For the Early Pleistocene, an age model for the well 16/1–8, from the central part of the northern North Sea based on Sr ages allows for dating of the prograding wedges filling the pre-Quaternary central basin. A regional calibration curve for the racemization of Asp in Elphidium excavatum is developed using published ages of radiocarbon-dated samples and samples associated with the previously identified Bruhnes/Matuyama (B/M) paleomagnetic boundary and a Sr age from this study. Based on all the available geochronological evidence, samples were assigned to marine oxygen isotope stages (MIS) with uncertainties on the order of 10–70 ka.Sr ages suggest a hiatus of <2 million years (Ma) possibly due to non-deposition or low sedimentation between the Utsira Formation (Pliocene) and the Early Pleistocene. An increase in sedimentation rates around 1.5 ± 0.07 Ma (∼MIS 51) may partly be due to sediment supply from rivers from the south-east and partly due to the extension of ice sheet around 1.36 ± 0.07 Ma from the Norwegian coast to the central North Sea. A possible basin-wide glaciation occurred around 1.1 Ma (∼ MIS 32) (upper regional unconformity/top of unit Q4 in this study), resulting in erosion and regional unconformity. Two interglacials in the Norwegian Channel have been dated: the Radøy Interglacial to 1.07 ± 0.01 Ma (possibly MIS 31, the ‘super interglacial’), and the Norwegian Trench Interglacial to 0.50 ± 0.02 Ma (possibly MIS 13). A massive till unit identified at the same stratigraphic level in all shallow borings may partly represent an extensive MIS 12 glaciation. This study shows that the combined use of amino acid racemization data and Sr isotope chronology can refine the chronological ambiguities of Quaternary North Sea sediments related partly to the impact of glacial processes.  相似文献