和(县)含(山)硬石膏矿成因类型、沉积环境及赋矿规律

通过和(县)含(山)硬石膏矿勘查资料,分析研究了该区含矿地层周冲村组(东马鞍山组)岩矿成因类型和代表性剖面岩相划分,认为周冲村组是在早中三叠世缓慢海退和干旱蒸发作用下形成的一套由浅滩—局限海夹潮坪—咸化潟湖—潮上萨布哈的蒸发岩建造,其中的硬石膏矿体主要沉积于咸化潟湖环境;认为早中三叠世的海退和海水咸化过程是循序渐进式发展的,其间发生了许多次小规模海侵或风暴潮,使得咸化潟湖海水的补给和蒸发保持了相对平衡,形成了巨厚硬石膏矿体沉积所需的持续稳定的海水盐度和环境条件;认为早中三叠世的海退有自西向东的退出趋势。同时指出,由于环境差异,本区东部的硬石膏矿品质好于西部。     

综合物探技术在钟姑地区三维地质填图和成矿预测中的应用效果

钟姑地区位于长江中下游成矿带,具有优越的成矿地质条件。本文通过在测区开展面积性和剖面重磁电测量,以岩石物性为基础,用已有地质钻孔资料做约束,对物探数据进行处理和反演计算,推断13条控制性剖面-2000m以浅地质结构,结合界面反演等处理方法,获得了测区主要地层界面埋深数据,编制了各个深度的地质中断图;在此基础上进行典型矿区分析和总结,建立地质-物探成矿模式,在合理的定向分析及定量计算条件下,圈定找矿靶区。     

Quartz OSL and TL dating of pottery,burnt clay,and sediment from Beicun archaeological site,China

This study focuses on characterizing the thermoluminescence (TL) and optically stimulated luminescence (OSL) of quartz in burnt clay, pottery, and the sediments unearthed from a Neolithic site, the Beicun site of the Liangzhu culture. It shows that the initial OSL signals (within 0.8 s) of most burnt clay and pottery sherds are not dominated by the fast component. Results of a heating simulation experiment of sediment quartz show that annealing at temperatures exceeding 600–800 °C decreased the proportion of the fast component in the initial signal slightly. In addition, the proportion of the medium component in the later signal (0.8–5 s) increased significantly, resulting in a decrease in the Fast Ratio value. Therefore, high annealing temperature may be an important reason for the slow decay rate of OSL signals of the burnt clay and pottery samples. The D_e(t) plot shows that most of the samples have thermally stable OSL component signals, which have no significant effect on the final OSL ages. The single-aliquot regenerative-dose (SAR) protocol was used to determine the OSL and TL ages for chunk burnt clay and pottery sherds. The high-precision age of the last archaeological heating event, such as sacrifice, burning, or domestic firing, can be obtained by determining the TL and OSL ages of a homogeneous chunk of burnt clay. The OSL results are consistent with the ¹⁴C age of carbon chips extracted from burnt clay. The age of the Beicun site is finally determined to be approximately 5000–5300 BP (BP represents before 2020), belonging to the early period of the Liangzhu culture.     

矿权的生产与经营--论地勘单位的改革与发展

矿权及矿权市场的建立,为地勘行业的找矿成果进入市场搭建了平台,矿权的生产与经营是国有地勘单位最具优势和竞争力的产业发展方向,商业性地质工作是地勘单位获取利润的重点,按市场经济的要求,以企业为主体,以局为单元,以效益为目的,地勘行业在社会经济发展中大有作为。     

Multidimensional statistical technique for detection of low contrast geochemical anomalies

In this article we propose an advanced technique for detecting low contrast geochemical anomalies using a set of features. There are three principal elements in this technique: (1) a statistical measure of the contrast of the anomaly, denoted as τ; (2) selection of a background population; and (3) reduction of the dimensionality of the feature space. In the frame of the model, which describes the statistical distribution of geochemical background as a multidimensional normal distribution of logarithms of concentrations, the index, τ, is a powerful test statistic for the hypothesis of abnormality of an observation. Maps of τ anomalies can be rigorously interpreted on the basis of statistical inferences. Under all equal conditions this technique allows the detection of geochemical anomalies with at least the same contrast (if the chemical elements in a background population are correlated, then even the better) as using selective extractions of metals from soil or other techniques for data processing. The advantages of the proposed technique are demonstrated both theoretically and on examples of rare-metal and copper–nickel mineral deposits.     

Influence of the ground profile on the reduction of earthquake motion at the filled man-made islands in the Kobe harbor during the 1995 Hyogoken Nambu earthquake

During the 1995 Hyogoken Nambu earthquake in Kobe, the ground motion at the filled man-made islands in the Kobe harbor was not as severe as that at the mainland. The building damage was also less compared to that on the mainland. It was found by comparative study of earthquake records that the magnitude of acceleration response on the ground surface decreases at the islands as opposed to the mainland. One dimensional effective stress analysis is adopted in this study. Input data has been generated from test results, e.g. the SPT N-value by standard penetration test and shear wave velocity V_s by PS logging. Results obtained by the analyses showed good agreement with the observed records, which is an indication of the suitability of the adopted analysis procedure. From this study, the followings are concluded. By the increase of SPT N-value of the filled layers, liquefaction near ground surface is restrained and damage modes such as ejection of water and soil can be prevented. Since the ground profile at the islands is that considerably soft filled layer and marine clay layers, etc. are present and the thickness of the surface layer is large, the initial natural period of the ground is above 1 s and the natural period is elongated further under the earthquake excitation, which is deemed to be the principal reason for the reduction of the earthquake motion at the ground surface.     

环境磁学研究现状和进展

环境磁学是八十年代逐步发展起来的具有学科交叉特点的边缘学科。它主要应用岩石和矿磁学研究磁性颗粒的搬运、沉积以及转化受大气圈、水圈和岩石圈环境变化影响的过程。近年来，环境磁学已提供了大量有关全球变化过程以及人类活动对环境影响等重要资料，其研究范畴迅速扩展，已成为当今地学的前沿学科之一。     

安徽省饮用天然矿泉水资源的基本特征与形成规律

安徽省属饮用天然矿泉水资源比较丰富的省份之一，产地多，但类型较为单一。在已通过鉴定的７４处矿泉水中，以偏硅酸锶型天然矿泉水最为普遍，占矿泉水总数的７６％，次有溴碘型天然矿泉水，开发条件优越，开发前景良好，其形成和分布具有明显的规律性。本文试图通过矿泉水赋存的地质环境、水化学特征和形成条件等的综合分析，进而划分饮用天然矿泉水的成因类型．并在勘查研究和开发利用方面提出有关意见和建议。     

煤矿区城市矿物气溶胶的SEM-EDX特征分析

采集煤矿区城市义马、平顶山、永城夏季大气PM₁₀样品,采用带能谱的扫描电镜(SEM-EDX)研究了PM₁₀中的矿物颗粒组成、成因及来源。结果表明,矿区矿物颗粒按化学成分共有5种主要类型,分别为"富Si"、"富Ca"、"富S"、"富K"、"富Cl"型。其中平顶山地区"富Si"颗粒占百分比最高(78%),矿物颗粒硫酸盐化程度小;永城地区硫酸盐化程度中等,几乎所有的"富Ca"碱性碳酸盐颗粒都硫酸盐化成石膏;义马地区矿物硫酸盐化程度最大,除石膏以外,还有一定量硫酸铵形成。永城和义马地区还出现了一定量的"富K"(12.7%)和"富Cl"(10.6%)颗粒,与秸秆焚烧活动有关。通过对3个矿区城市PM₁₀硫酸盐化程度对比可以发现,偏碱性的碳酸盐矿物、煤炭燃烧和秸秆焚烧燃烧释放出大量的酸性SO₂以及较高的空气湿度,均有利于硫酸盐化的进行,硫酸盐颗粒的形成对煤矿区城市的区域性气候具有一定影响。     

主应力轴旋转对地铁荷载作用下 软黏土累积变形的影响

为了定量评价主应力轴旋转对地铁荷载作用下隧道下卧软黏土累积变形的影响,通过有限元方法并结合实测数据的验证对地铁荷载下地基土的应力路径进行分析;在此基础上,借助空心圆柱仪对这一复杂应力路径进行室内模拟和对比试验研究。结果表明：主应力轴旋转增大了软黏土的累积变形,且最大有效主应力比（有效最大主应力与有效最小主应力之比）越大、或加载频率越高增大更明显。在实际地铁荷载和通常隧道埋深条件下,考虑主应力轴旋转使软黏土的累积变形增加9%～23%（加载频率越高,增加越大）。可用常规循环三轴的累积变形试验结果乘以土体分别在有、无主应力轴旋转下变形的比值,来预估实际地铁荷载下软黏土的累积变形,初步研究得到该比值与土体的最大有效主应力比之间存在幂函数关系。