同点激发电位法在铀矿普查中的运用

本文介绍了同点激发电位法在不同地区、不同地质条件下的铀矿化点上的野外工作实例。试验结果表明:其找矿效果良好。在野外相同条件下,与其他方法对比的结果,同点激发电位法具有探测深度大,异常显示较清晰,可以区分真假异常,能够较准确地定量解释二次激发电位(V_2)异常,仪器设备较轻便等优点。     

氡气异常解释方法的初步探讨

在铀矿勘探中,根据氡气异常计算矿体埋深的工作是十分重要的。本文从运用测氡及其子体的方法寻找深部铀矿的事实出发,探讨了氡气运移的方式及其可能分布的模式,并对M.M.索科洛夫的实验结果进行了初步的理论讨论。同时,对根据氡气异常计算矿体埋深的解释问题进行了探索性的研究。本文所提出的方法,在一定的地质条件下,原则上适用于各种放射性测量异常的解释方法。实践表明,本法在矿床勘探工作中能提供关于矿体的某些参数(埋深和产状),有一定的实用价值。     

Decoupled Erosion of Authigenic and Detrital Components in Soil

In the study of surface processes, it is generally assumed that erosion occurs equally throughout the soil profile so that chemical depletion of the topsoil can represent the intensity of chemical weathering and the duration of surface exposure to cosmogenic radiation can reflects the soil residence time, and then the rate of erosion can be calculated. In comparison with fresh bedrock, the depletion of soluble elements in soil mainly comes from fine-grained secondary clay components, while the depletion degree of detrital minerals is weak. The preferential erosion of fine-grained secondary clay will lead to the underestimation of weathering intensity, and the retention time of detrital mineral will be longer than the total retention time of soil， and thus the soil erosion rate will be underestimated. Based on the uranium isotope comminution ages of soil in the Lesotho Highlands, we found that erosion operates differentially between the detrital and authigenic components of the soil. Uranium isotope comminution ages show a soil residence time of (543±32) ka for the detrital particles. In contrast, soil residence time of the authigenic phases is constrained to be (22±11) ka according to the accumulation of recoiled ²³⁴U from the absorbed ²³⁸U to river water. The residence time of secondary clay matches with the regional erosion rate 24-33 t/(km²·a) calculated from weathering flux, indicating that secondary clay is the main component of soil erosion. The results indicate that the decoupled erosion of different components in soil may be common. This finding implies that the intensity of weathering based on bulk soil erosion and the rate of soil erosion determined by exposure dating of coarse soil grains may be invalidated due to the preferential erosion of authigenic particles. As a result, a lower estimate of weathering flux may be made, and therefore the role of chemical weathering in the global carbon cycle could be underestimated.     

放射性－遥感技术在鞍本地区铀成矿环境分析及远景预测中的应用

作者运用放射性－遥感（即光－能谱）集成技术对鞍本地区区域地质构造格架及铀成矿环境进行了研究，提出辽阳晚太古代花岗质穹窿构造和两条古深大断裂对该区构造格架、岩浆活动及铀成矿起重要的控制作用；在花岗质岩石的物源和成因方面得出了某些新的认识，并据此总结出铀成矿机理“三要点”，预测了铀成矿远景区，指出弓长岭南部与连山关花岗岩体西部之间是最有利的成矿远景区。同时，运用该技术对燕山期花岗岩岩体进行了等级体制填图的探索，结果表明，这是一种快速、准确、高效的新方法。     

山东胶莱盆地——一个地洼盆地结构与金矿形成关系研究

山东胶莱盆地结构由前地槽及地槽、地台及地洼构造层组成 ,实为一地洼盆地。盆地所有金矿均为地洼活动的产物。在地洼活动初期 ,形成胶莱盆地并沉积下白垩统莱阳群一段含碳岩系矿源层 ;中期 ,地洼活动加强 ,盆地沉积大量粗碎屑岩 ,有机质成矿作用形成顺层展布的金矿体 ;晚期 ,地洼活动进一步发展 ,叠置在先期金矿带上的新聚矿体系形成 ,成矿热液除改造原有金矿床外还形成新的金矿床。最终定位形成胶莱盆地金矿全貌     

古地温方法在热液金属矿床研究中的应用

充足的热源是形成热液矿床必备条件之一，古地热条件的恢复是热液矿床研究的重要环节。在归纳常见的古地温方法的基础上，以热液铀矿床古地温场的有限单元模拟为例，说明古地温方法在热液金属矿床研究中的应用。     

苏红图－乌后旗中、新生代砂岩盆地铀成矿条件分析

本文依据前苏联水成铀矿床成矿条件的主要评价准则［１］，分析、研究了内蒙古中部的苏红圈－乌后旗中、新生代砂岩盆地内层间氧化带型铀矿的成矿条件。研究表明，该盆地的形成始于早、中侏罗世，进入新生代后演化成为一个以渗入水动力体制为主的自流盆地。盆地具备比较有利的铀成矿条件，是一个值得进一步探索的地区。     

铀矿石及含铀岩石中四价铀和六价铀分析方法的研究

本文介绍的是测定铀矿石及含铀岩石中铀（Ⅳ）和铀（Ⅵ）的新方法。本分析方法设计了独特的样品分解体系和溶解、分离程序。从矿样在低温下（４０℃±５℃）分解、四氟化铀沉淀的形成、铀（Ⅵ）及部分干扰离子溶解进入溶液，到固、液两相的分离，整个过程在２ｍｉｎ内完成。本方法确保了样品处理过程中铀的价态不变，并使铀（Ⅵ）完全溶出，铀（Ⅳ）快速沉淀以及两者定量分离，是测定铀矿石及含铀岩石中铀（Ⅳ）和铀（Ⅵ）的简便、快速的分析方法，其准确度和精密度可满足地质科研的需要。     

Raw materials activities of the manhattan project on the colorado plateau

The Manhattan Project was a highly secret project during World War II to develop the atomic bomb, and included the acquisition of raw materials. It was carried out by the Army’s Corps of Engineers Manhattan Engineer District. In the United States, 2,698,000 pounds of uranium oxide were acquired at various vanadium mills on the Colorado Plateau, mainly from the treatment of tailings. Geologic investigations conducted by a contractor, Union Mines Development Corporation, laid the ground work for the exploration activities of the Atomic Energy Commission which succeeded the Manhattan Engineer District in 1947     

U–salinity relationships in the Mediterranean: Implications for Th:U particle flux studies

Knowledge of the ²³⁸U concentration in seawater is important for ²³⁴Th:²³⁸U disequilibrium studies of particle fluxes. However, these concentration data are normally obtained through a standard relationship between ²³⁸U and salinity, which has been determined for the open ocean. This study examines ²³⁸U data from both the open Mediterranean and the coastal Thermaikos Gulf, Greece, and compares it to the open ocean. No deviation from the open ocean ²³⁸U–salinity relationship was found for the Thermaikos Gulf, but some enhancement was noted close to Thessaloniki in the vicinity of a phosphate fertiliser plant. The open Mediterranean data showed a small enhancement relative to the open ocean. Although an analytical bias could not be ruled out, a review of ²³⁸U and salinity data in the literature shows that the standard relationship may not be as robust as is often assumed and the 1% uncertainty typically used is not justified at the present time. Nevertheless, salinity-based derivations continue to be the most appropriate means of determining ²³⁸U concentrations for routine applications. We propose a new relationship that accounts for the uncertainties observed, i.e. ²³⁸U (dpm l^− 1) = (0.0713 ± 0.0012) × salinity.