硅酸盐和金属氧化物矿物氧同位素组成的CO_2激光氟化分析

我室采用MIR 10型CO2 激光器 ,在一种富BrF5的氛围中使激光对硅酸盐和氧化物矿物样品加热形成O2 ,经多次纯化后用 5 的分子筛吸收 ,再直接送至气体质谱仪进行氧同位素比值测定。这个实验流程与传统方法相比的改进不仅在使用激光加热技术及样品的放置上 ,而且在直接采用O2 而不是CO2 进行质谱测定。采用O2 进行直接分析的优点不仅避免了向CO2 转化过程中的潜在同位素分馏 ,而且能够得到样品的δ1 7O值 ,因此为宇宙样品分析提供了可能。CO2 激光氟化技术的优点是所需样品量小 (可低达 1～ 2mg) ,因此能够分析微小岩石区域或单矿物晶体内的氧同位素分布。同时 ,激光可以达到非常高的温度 (>40 0 0K) ,因此能够对某些难熔矿物 (如锆石、蓝晶石、橄榄石等 )进行氧同位素分析。     

大口径绳索取心钻进工艺在页岩气地质调查川蔺参1井中的应用

为了获取参数井压裂设计的相关参数,需要对井眼进行阵列声波测井和微侧向电阻率测井,需要采取大直径岩心进行力学实验。采用固体岩心钻探取心工艺,钻孔口径难以达到物探测井仪器入井要求,岩心直径也不能满足实验要求,必须采用大口径取心工艺才能满足设计要求。同时,常规取心工艺难以满足页岩气勘探对岩心（页岩或者煤心）提升时间的要求,绳索取心工艺在这方面优势明显。本篇介绍了大口径绳索取心工艺在页岩气地质调查井川蔺参1井的成功应用,根据大口径绳索取心钻具的结构特点,结合目的层岩性特征,总结了合理的取心钻进工艺参数和技术保障措施,取得了较好的效果。     

Identification and micro‐stratigraphy of hyperpycnites and turbidites in Cretaceous Lewis Shale,Wyoming

Sandy hyperpycnal flows and their deposits, hyperpycnites, have been documented in modern environments and, more recently, in Cretaceous and Tertiary strata; they may be more common in the rock record, and within petroleum reservoirs, than has been previously thought. Muddy hyperpycnites also occur within the rock record, but these are more difficult to document because of their finer‐grained nature and lack of common sedimentary structures. This paper documents the presence of submarine slope mudstone and siltstone hyperpycnites (and muddy turbidites) in the delta‐fed, Upper Cretaceous Lewis Shale of Wyoming; based on field measurements, analyses of rock slabs and thin sections, and laser grain‐size distributions. Four lithofacies comprise laminated and thin‐bedded mudstones that are associated with levéed channel sandstones: (L1) grey, laminated, graded mudstone with thin siltstone and sandstone interbeds; (L2) dark grey to tan, laminated mudstone with very thin siltstone and sandstone stringers; (L3) light grey, laminated siltstones; and (L4) laminated mudstones and siltstones with thin sandstone interbeds. Two styles of mudstone grain‐size grading have been documented. The first type is an upward‐fining interval that typically ranges in thickness from 2·5 to 5 cm. The second type is a couplet of a lower, upward‐coarsening interval and an upper, upward‐fining interval (sometimes separated by a micro‐erosion surface) which, combined, are about 3·8 cm thick. Both individual laminae and groups of laminae spaced millimetres apart exhibit these two grain‐size trends. Although sedimentary structures indicative of traction‐plus‐fallout sedimentary processes associated with sandier hyperpycnites are generally absent in these muddy sediments, the size grading patterns are similar to those postulated in the literature for sandy hyperpycnites. Thus, the combined upward‐coarsening, then upward‐fining couplets are interpreted to be the result of a progressive increase in river discharge during waxing and peak flood stage (upward increase in grain‐size), followed by waning flow after the flood begins to abate (upward decrease in grain‐size). The micro‐erosion surface that sometimes divides the two parts of the size‐graded couplet resulted from waxing flows of sufficiently high velocity to erode the sediment previously deposited by the same flow. Individual laminae sets which only exhibit upward‐fining trends could be either the result of waning flow deposition from either dilute turbidity currents or from hyperpycnal flows. The occurrence of these sets with the size‐graded couplets suggests that they are associated with hyperpycnal processes.     

应用遥感影像预测皖南细微浸染型金矿的认识

本文详细论述了安徽省细微浸染型金矿成矿带的地质背景，利用遥感影像对其地质背景进行了解译，结合地质、物化探等多种手段，提出了２个细微浸染型金矿的成矿远景区     

基于降水微物理特征测量仪的雨滴形状观测与分析

利用自主研制的降水微物理特征测量仪开展降水观测试验,得到了大量的雨滴图像。研究了异常雨滴图像的形成原因和处理方法,以此为基础重点研究了在极坐标下基于Akima插值的数字雨滴图像矢量化方法,得到了雨滴平均形状特征和轴比分布特征。结果表明,直径小于1 mm的雨滴以圆形为主,在1.0~3.0 mm的雨滴以椭圆形为主,大于3.0 mm的雨滴逐渐呈现顶部凸起,底部偏平的形状;雨滴的平均轴比分布与经验分布一致,相互之间差异在±0.04 mm范围以内;雨滴的平均轴比与经验模型的差值在粒径3.4~3.8 mm出现峰值,该范围内的雨滴较经验关系具有更圆的形状特性。     

两种海洋单胞藻浓缩与保存效果的研究

研究了小球藻和球等鞭金藻分别用明矾和石灰水浓缩以及两种藻的浓缩液在常温(20 ±1℃)、低温(0—4℃)﹑冷冻(-30±1℃)三种温度条件下保存的结果,并对浓缩保存前后藻液的饵料效果进行了对比试验。 结果表明:(1)小球藻的浓缩以80±5ppm的明矾液及4%的石灰水效果最好;(2)球等鞭金藻的浓缩以100±10ppm的明矾液及6%的石灰水效果最好; (3)保存方法以加入保护剂甘油并置于-30℃ 冰箱中效果最好,小球藻和球等鞭金藻的存活率分别为95%和93%;(4)低温保存前后藻的脂肪酸分析结果表明高度不饱和脂肪酸(HUFA)的含量变化不明显;(5)用浓缩保存藻投喂中国对虾和轮虫的效果与普通藻无显著差异。     

Generation of a realistic 3D sand assembly using X‐ray micro‐computed tomography and spherical harmonic‐based principal component analysis

Three‐dimensional particle morphology is a significant problem in the discrete element modeling of granular sand. The major technical challenge is generating a realistic 3D sand assembly that is composed of a large number of random‐shaped particles containing essential morphological features of natural sands. Based on X‐ray micro‐computed tomography data collected from a series of image processing techniques, we used the spherical harmonics (SH) analysis to represent and reconstruct the multi‐scale features of real 3D particle morphologies. The SH analysis was extended to some highly complex particles with sharp corners and surface cavities. We then proposed a statistical approach for the generation of realistic particle assembly of a given type of sand based on the principle component analysis (PCA). The PCA aims to identify the major pattern of the coefficient matrix, which is made up of the SH coefficients of all the particles involved in the analysis. This approach takes into account the particle size effect on the variation of particle morphology, which is observed from the available results of micro‐computed tomography and QICPIC analyses of sand particle morphology. Using the aforementioned approach, two virtual sand samples were generated, whose statistics of morphological parameters were compared with those measured from real sand particles. The comparison shows that the proposed approach is capable of generating a realistic sand assembly that retains the major morphological features of the mother sand. Copyright © 2016 John Wiley & Sons, Ltd.     

A three‐phase thermo‐hydro‐mechanical finite element model for freezing soils

Artificial ground freezing (AGF) is a commonly used technique in geotechnical engineering for ground improvement such as ground water control and temporary excavation support during tunnel construction in soft soils. The main potential problem connected with this technique is that it may produce heave and settlement at the ground surface, which may cause damage to the surface infrastructure. Additionally, the freezing process and the energy needed to obtain a stable frozen ground may be significantly influenced by seepage flow. Evidently, safe design and execution of AGF require a reliable prediction of the coupled thermo‐hydro‐mechanical behavior of freezing soils. With the theory of poromechanics, a three‐phase finite element soil model is proposed, considering solid particles, liquid water, and crystal ice as separate phases and mixture temperature, liquid pressure, and solid displacement as the primary field variables. In addition to the volume expansion of water transforming into ice, the contribution of the micro‐cryo‐suction mechanism to the frost heave phenomenon is described in the model using the theory of premelting dynamics. Through fundamental physical laws and corresponding state relations, the model captures various couplings among the phase transition, the liquid transport within the pore space, and the accompanying mechanical deformation. The verification and validation of the model are accomplished by means of selected analyses. An application example is related to AGF during tunnel excavation, investigating the influence of seepage flow on the freezing process and the time required to establish a closed supporting frozen arch. Copyright © 2013 John Wiley & Sons, Ltd.     

Continuous versus event‐based sampling: how many samples are required for deriving general hydrological understanding on Ecuador's páramo region?

As a consequence of the remote location of the Andean páramo, knowledge on their hydrologic functioning is limited; notwithstanding, these alpine tundra ecosystems act as water towers for a large fraction of the society. Given the harsh environmental conditions in this region, year‐round monitoring is cumbersome, and it would be beneficial if the monitoring needed for the understanding of the rainfall–runoff response could be limited in time. To identify the hydrological response and the effect of temporal monitoring, a nested (n = 7) hydrological monitoring network was set up in the Zhurucay catchment (7.53 km²), south Ecuador. The research questions were as follows: (1) Can event sampling provide similar information in comparison with continuous monitoring, and (2) if so, how many events are needed to achieve a similar degree of information? A subset of 34 rainfall–runoff events was compared with monthly values derived from a continuous monitoring scheme from December 2010 to November 2013. Land cover and physiographic characteristics were correlated with 11 hydrological indices. Results show that despite some distinct differences between event and continuous sampling, both data sets reveal similar information; more in particular, the monitoring of a single event in the rainy season provides the same information as continuous monitoring, while during the dry season, ten events ought to be monitored. Copyright © 2016 John Wiley & Sons, Ltd.     

方解石811N:一种可能的微区碳氧锶同位素分析标准

同位素标准物质是同位素分析的基准物质和数据比较的重要依据。方解石811作为碳酸盐碳氧同位素的实验室标准物质,具有良好的适用性,但由于制备时间久远,存量日益减少,且性状信息缺乏,影响了该标准在微区微量分析中的运用。本次研究选用未制备的811方解石(811N)作为研究对象,结合多种分析技术从不同尺度对其矿物组成、元素含量分布、碳氧同位素组成进行分析,揭示其相关信息及规律,并探讨了其Sr同位素组成,从而为下一步811N的制备和使用提供参考信息,有助于该样在不同碳酸盐分析和研究,特别是微区微量元素和同位素中的运用。实验结果表明,方解石811N较为纯净,主要为方解石,只含有微量的白云石、针铁矿、黏土矿物;除主要化学成分(CaCO₃)外,含有微量的Mg、Mn、Sr、Si、REE、U、Th等元素,Mg、Mn、Sr含量在整体分布上存在一定的变化,但在局部相对均匀。碳氧同位素组成整体差异程度相对较小,且其差异程度和元素均匀性呈对应关系,主要区域碳氧同位素组成均匀。Sr同位素组成在不同区域中无明显差异。本次研究认为811N是合适的碳酸盐碳氧同位素分析标准物质,该样制备后能够满足碳氧同位素分析和研究的需要,同时该样具备适用于微区微量C、O、Sr同位素分析和研究的潜力。