The δ60/58Ni Values of Twenty‐Six Selected Geological Reference Materials

The high‐precision δ^60/58Ni values of twenty‐six geological reference materials, including igneous rocks, sedimentary rocks, stream sediments, soils and plants are reported. The δ^60/58Ni values of all samples were determined by double‐spike MC‐ICP‐MS (Nu Plasma III). Isotope standard solution (NIST SRM 986) and geological reference materials (BHVO‐2, BCR‐2, JP‐1, PCC‐1, etc.) were used to evaluate the measurement bias and intermediate precision over a period of six months. Our results show that the intermediate precision of Ni isotope determination was 0.05‰ (2s, n = 69) for spiked NIST SRM 986 and typically 0.06‰ for actual samples, and the δ^60/58Ni _{NIST SRM 986} values were in excellent agreement with previous studies. Eighteen high‐precision Ni isotope ratios of geological reference materials are first reported here, and their δ^60/58Ni values varied from ?0.27‰ to 0.52‰, with a mean of 0.13 ± 0.34‰ (2s, n = 18). Additionally, SGR‐1b (0.56 ± 0.04‰, 2s), GSS‐1 (?0.27 ± 0.06‰, 2s), GSS‐7 (?0.11 ± 0.01‰, 2s), GSD‐10 (0.46 ± 0.06‰, 2s) and GSB‐12 (0.52 ± 0.06‰, 2s) could potentially serve as candidate reference materials for Ni isotope fractionation and comparison of Ni isotopic compositions among different laboratories.     

岩石化学计算系统

岩石化学是以岩石全分析数据为基础,研究各种岩石及其自然组合的化学联系,分类命名,成因,演化及其与成矿元素的内在联系的一门科学.岩石化学计算系统主要由数据的编辑处理,岩石化学计算与成图,岩石化学数据管理三大部份组成.该系统汇集了国内外岩石化学计算方法202种,附图242张,使岩石化学分析数据的搜集,整理,计算成图等形成一个完整的微机处理系统.     

石笋氧同位素和微量元素记录的陕南地区4200～2000a B.P.高分辨率季风降雨变化

基于陕南祥龙洞石笋XL2的19个230Th年龄、218个氧同位素分析以及896个Sr/Ca分析数据,高分辨率重建了4200～1972a B.P.期间陕南地区季风降雨变化.重建结果显示陕南地区这一时期季风降雨有显著的127～105a和57a周期,可能分别受控于太阳活动、PDO和/或AMO的变化.重建时段有3次百年尺度的干旱事件,分别发生于2200～2100a B.P.,2900～2700a B.P.和3600～3400a B.P.,其中2900～2700a B.P.干旱事件对应于北大西洋地区2.8ka冷事件.对比研究显示,尽管祥龙洞石笋和董哥洞石笋δ18O记录整体一致,但除了2900～ 2700aB.P.干旱事件之外,其他两次干旱事件在董哥洞石笋记录中并不明显.而尽管总体上祥龙洞和和尚洞石笋δ18O记录的差异要大,但XL2的3次干旱事件在和尚洞记录都有明显体现.有精确年代控制的祥龙洞、董哥洞及和尚洞石笋氧同位素记录的差异,揭示晚全新世我国季风降雨在十一百年尺度存在区域差异.     

The Paleo－Environmental Significance of Sr and Ca Contained in Acid－Soluble Fraction of Plateau Loess Deposits in Xining Basin

The Xining Basin,located on northeastern Qinghai-Xizang Plateau,is adjacent to the Qaidam Bsim and Gobi-desert.Therefore,thick,integrated deposits of loess or paleo-sol sequence were well developed.As is well known,there is much paleo-environmental information recorded in loess and plaeo-sol.So if we deal with paleo-environmental index from different an gles ,especially from loess geochemistry,some important and detailed paleo-environmental evolutional information will be acquired.Based on this,the authors determined the contents of Sr and Ca contained in acid-soluble fraction from the bottom to the top of the Panzishan section.This section was obtained through making a well about 17 m in depth,including S1 paleo-sol that was developed during the last interglacial period.According to the results,it is found that variations in contents of Sr and Ca are well correlated with conversion of loess and paleo-sol.In loess deposits,the contents of Sr and Ca are higher than those in paleo-sol deposits.It is known that loess was deposited under cold-dry climate conditions and paleo-sol was developed during warm-humid climate episodes.It is concluded that due to their mobile behaviors,under cold-dry climate conditions,Sr and Ca are stagnant during weak weathering,but under warm-humid climate conditions,Sr and Ca are easily leached and transported in aqueous solution.Therefore,they can be utilized as indicatiors of climate changes.Moreover,variations in contents of Sr and Ca are more sensitive than susceptibility.The mobile behaviors of Sr and Ca contained in acid-soluble fraction can serve as a new quantitative index to evaluate paleo-environmental changes on the plateau.     

Investigations and assessment of the landslide hazards of Fengdu county in the reservoir region of the Three Gorges project on the Yangtze River

The spatial database of landslides in Fengdu County of the reservoir region of the Three Gorges project (TGP) on the Yangtze River was compiled from a variety of different sources including field investigations on landslides, existing catalogues and archives on landslides, reports of meteorological events and human engineering activities that triggered slope failures. The major factors that are found to have affected the slope stabilities are outlined, and an assessment and zonation of landslide hazards of the region is made using an integrated information model, which is divided into destructive, disastrous, likely disastrous and essentially non-disastrous areas from the assessment of landslide hazards. The destructive and disastrous areas are respectively 1.9 and 13.8% of the total region, mostly being nearby townships, highways along the south bank of the Yangtze River and residential quarters along two flanks of the Yangtze River and its distributaries, that will impose direct impact to highway transportation and residential lives, and may effect to some degree the navigation of the Yangtze River, reservoir banks, and building of cities and towns.     

氧化锰矿物的生物成因及其性质的研究进展

土壤中的氧化锰矿物是原生矿物风化和成土过程的产物,是最具反应活性的一类矿物,决定着环境中许多物质的形态、迁移和转化,在元素生物地球化学循环中起着重要的作用,其形成机制和环境效应备受关注。已有的研究表明,环境中氧化锰的形成与微生物作用紧密相关,微生物作用可使自然环境中的Mn(Ⅱ)氧化速率提高105倍。参与Mn(Ⅱ)氧化的微生物在环境中广泛存在,已知的典型锰氧化细菌分布在变形菌门、放线菌门或厚壁菌门,它们均通过胞外聚合物中的多铜氧化酶来催化氧化Mn(Ⅱ)。细菌氧化Mn(II)成Mn(Ⅳ)是酶催化的两个连续的快速单电子传递过程,Mn(Ⅲ)在溶液中以与酶结合的瞬时中间态出现。生物形成氧化锰的最初形态为层状锰矿物,与δ-MnO2或酸性水钠锰矿很类似,且结晶弱,粒径小,锰氧化度高,结构中的八面体空穴多,因而比化学形成的氧化锰具有更强的吸附、氧化等表面活性。环境中Mn(Ⅱ)微生物氧化及形成的Mn(Ⅲ)中间体与碳、氮、硫等生命元素的地球化学循环的关系令人关注。     

论当前我国北西部铀矿勘查关键技术

本文提出当前我国北西部铀矿勘查两项关键技术──中国北西部寻找大型超大型可地浸砂岩铀矿勘查技术和找矿勘探过程中地浸可行性评价技术，并论述了技术内容和技术开发目标。两项关键技术的开发研究和落实对扩大我国铀矿资源有现实意义。     

基于GMS的三维TOUGH2模型及模拟

GMS和TOUGH2均是应用广泛的地下流动系统数值模拟软件,其中,GMS界面友好,功能强大;而TOUGH2虽具有强大的数值计算能力,但缺乏友好的可视化前后处理界面。本文借助GMS强大的前处理能力,基于概念模型建立了三维复杂模型,把GMS/MODFLOW三维数值模型(包括网格数据、岩性数据、初始和边界数据等)转化为TOUGH2数值模型进行数值计算。通过两个计算实例(含水层水平没有起伏和有起伏)对比分析了GMS/MODFLOW和TOUGH2计算结果的差异。结果显示,该方法可以快速地建立刻画复杂地质条件的TOUGH2模型,计算结果与GMS/MODFLOW差异很小,说明两个软件均有很高的可信度;同时,该方法发挥了两个软件各自的优势,为进行更为复杂的多相流动数值模拟提供了可行性。     

天气预报分析型数据模型及生成

将原始数据转换为分析型数据,增强用户对海量数据的分析能力,是数据仓库技术最核心、最有价值的思想,也是数据仓库在气象领域应用的基础。该文针对天气预报领域数据空间性、瞬变性、物理性和多尺度性等特点,提出了五元组描述的天气预报分析型数据概念模型;总结了生成分析型数据的固定区域统计、划分区域统计、基本天气系统识别和天气学概念模型识别4种聚集变换,并对其关键技术进行了讨论。提出了基本天气系统自动识别的滤波-划分-测量算法,探讨了针对气象数据特点的模糊空间关系,定义了进行天气学概念模型识别的空间模糊产生式规则,并针对空间数据给出了定位条件等扩展。     

孤立金属尖端的电晕触发阈值

为了得到金属尖端在发生电晕放电时尖端处的电场强度,该文首先采用实验室实验得到不同高度、不同形状、不同材质的金属尖端发生电晕放电时的环境电场阈值;再采用有限元法计算二维泊松方程,得到尖端处电晕触发阈值,由此得出以下结论:环境电场阈值随金属尖端高度的增大基本呈线性减小趋势,随着尖端越来越尖,环境电场阈值呈先减小后增大的变化趋势;高度、形状对金属物尖端处电晕触发阈值无影响,尖端处电晕阈值为定值;给出尖端处电晕触发阈值为158.75 kV·m-1与空间分辨率的拟合公式,可为今后电晕放电数值模拟中判断电晕放电的起始时刻提供参考。