区域土壤环境地球化学研究——异常成因判别·环境质量·污染程度评价的思路与方法

从概念内涵和应用目标出发,认为土壤环境地球化学质量评价应该分为质量现状和污染程度两个方面.在此基础上探讨了区域地球化学资料在土壤环境现状质量评价、异常成因识别、污染元素累积速率和土壤污染程度评价研究的基本思路和方法.     

日光温室低温寡照灾害指标

文章根据1965～2000年河北省日光温室试验观测资料及各地历年低温寡照对蔬菜的影响程度，确定了低温寡照灾害等级指标，分析了低温寡照的时空分布规律，20世纪80年代以后，河北省各市低温寡照发生次数比60、70年代明显增多；随着纬度增高，河北省低温寡照发生次数明显减少，危害程度明显减轻。     

有机质热演化与极低级变质作用

岩石中有机质热演化特征可以灵敏于反映岩石的成岩作用到变质作用之间（即极低级变质作用）的温度、压力变化情况。笔者对有机质热变指标在极低级变质作用界线、变质带划分和变质作用温度、压力和时间演化等方面的应用进行了综述和探讨。     

Grade estimation using fuzzy- set algorithms

This paper presents a new approach for estimating unknown ore grades within a mining deposit in a fuzzy environment using fuzzy c- means clustering and a fuzzy inference system. Based on a collection of cluster centers obtained from fuzzy c- means, a fuzzy rule base and fuzzy search domains are established to compute grades at these cluster centers. These cluter center- grade pairs act as control information in the fuzzy space- grade system in order to infer unknown grades on the basis of fuzzy interpolation, fuzzy extrapolation, and a defuzzification process of fuzzy control.     

The tectono‐metamorphic evolution of the very low‐grade hangingwall constrains two‐stage gneiss dome formation in the Montagne Noire (Southern France)

The Montagne Noire in the southernmost French Massif Central is made of an ENE‐elongated gneiss dome flanked by Palaeozoic sedimentary rocks. The tectonic evolution of the gneiss dome has generated controversy for more than half a century. As a result, a multitude of models have been proposed that invoke various tectonic regimes and exhumation mechanisms. Most of these models are based on data from the gneiss dome itself. Here, new constraints on the dome evolution are provided based on a combination of very low‐grade petrology, K–Ar geochronology, field mapping and structural analysis of the Palaeozoic western Mont Peyroux and Faugères units, which constitute part of the southern hangingwall of the dome. It is shown that southward‐directed Variscan nappe‐thrusting (D₁) and a related medium‐P metamorphism (M₁) are only preserved in the area furthest away from the gneiss dome. The regionally dominant pervasive tectono‐metamorphic event D₂/M₂ largely transposes D₁ structures, comprises a higher metamorphic thermal gradient than M₁ (transition low‐P and medium‐P metamorphic facies series) and affected the rocks between c. 309 and 300 Ma, post‐dating D₁/M₁ by more than 20 Ma. D₂‐related fabrics are refolded by D₃, which in its turn, is followed by dextral‐normal shearing along the basal shear zone of both units at c. 297 Ma. In the western Mont Peyroux and Faugères units, D₂/M₂ is largely synchronous with shearing along the southern dome margin between c. 311 and 303 Ma, facilitating the emplacement of the gneiss dome into the upper crust. D₂/M₂ also overlaps in time with granitic magmatism and migmatization in the Zone Axiale between c. 314 and 306 Ma, and a related low‐P/high‐T metamorphism at c. 308 Ma. The shearing that accompanied the exhumation of the dome therefore was synchronous with a peak in temperature expressed by migmatization and intrusion of melts within the dome, and also with the peak of metamorphism in the hangingwall. Both, the intensity of D₂ fabrics and the M₂ metamorphic grade within the hangingwall, decrease away from the gneiss dome, with grades ranging from the anchizone–epizone boundary to the diagenetic zone. The related zonation of the pre‐D₃ metamorphic field gradients paralleled the dome. These observations indicate that D₂/M₂ is controlled by the exhumation of the Zone Axiale, and suggest a coherent kinematic between the different crustal levels at some time during D₂/M₂. Based on integration of these findings with regional geological constraints, a two‐stage exhumation of the gneiss dome is proposed: during a first stage between c. 316 and 300 Ma dome emplacement into the upper crust was controlled by dextral shear zones arranged in a pull‐apart‐like geometry. The second stage from 300 Ma onwards was characterized by northeast to northward extension, with exhumation accommodated by north‐dipping detachments and hangingwall basin formation along the northeastern dome margin.     

Temporal stability of soil moisture in an oasis of northwestern China

Temporal stability of soil moisture has been widely used in hydrological monitoring since it emerged. However, the spatial analysis of temporal stability at the landscape scale is often limited because of insufficient sampling numbers. This work made an effort to investigate the spatial variations of temporal stability of soil moisture in an oasis landscape. The specific objectives of the study were to explore the spatial patterns of temporal stability and to determine the controlling factors of temporal stability in the desert oasis. A time series of soil moisture measurements were gathered on 23 occasions at 118 locations over 3 years in a rectangular transect of approximately 100 km². The nonparametric Spearman's rank correlation coefficient, standard deviation of relative difference (SDRD), and mean absolute bias error (MABE) were used to quantify the temporal stability of soil moisture. Results showed that the temporal stability of soil moisture was depth dependent and season dependent. The spatial pattern of soil moisture in a deep soil layer and between two same seasons generally had a high temporal stability. SDRD and MABE were spatially autocorrelated and exhibited strong spatial structures in the geographic space. The concept of temporal stability can be extended to describe the time‐stable areas of soil moisture with geostatistics. There were great differences between SDRD and MABE in describing the temporal stability of soil moisture and in identifying the controlling factors of temporal stability. In this case, MABE was a better alternative to estimate the areal mean soil moisture using representative locations than SDRD. Land use type, soil moisture condition, and soil particle composition were the dominant controls of temporal stability in the oasis. These insights could help to better understand the essence of temporal stability of soil moisture in arid regions.     

架子台沟低品位铅锌矿原生晕地球化学特征及深部矿产预测

对架子台沟一带1:50 000化探异常检查中,地表发现有铅锌矿化显示,经对激电测深异常深部钻探验证发现有低品位锌矿(化)体。通过系统采集0号勘探线上的2个钻孔中岩石、矿石样品,进行原生晕特征研究分析表明:矿体近矿元素为Ag、Pb、Zn、Cd,尾矿元素为W、Sn、Bi;轴向分带序列由上至下为:Pb-Au-Ag-Mo-Bi-Sn-Cu-Cd-W-Zn。对成矿元素与相关金属元素进行聚类分析、因子分析,并结合激电测深结果,认为在矿体的侧部、深部仍可能有盲矿体。     

聚龙小镇DZK1地热勘查孔钻探施工技术

地热勘查孔（探采结合孔）是在矿山钻探施工工艺的基础上进行的探索性施工。着重介绍了福建省泉州市聚龙小镇DZK1地热勘查孔在钻探施工过程中遇到的施工难题以及新技术、新工艺的应用。如大口径单管取心、空压机洗井和活塞洗井相结合的洗井方法、套管的隔级使用、深孔测试钻杆密闭性、深孔磨钻头、在涌水量大的地层钻进等。     

序贯高斯模拟在矿石品位估计中的应用研究

随机模拟是地质统计方法的重要内容。在矿石品位估计方法中克里格方法作为一种无偏估计方法,常被用于矿石品位的估计。但克里格法估值存在平滑效应。作者在分析序贯高斯模拟和普通克里格法基本原理的基础上,运用序贯高斯模拟方法和普通克里格方法对某铁矿体内全铁(TFe)品位进行估计,给出了品位估计结果模型。研究从勘探线方向、垂直勘探线方向和竖直方向分别计算变差函数,对球状模型、指数模型、高斯模型的变差函数拟合效果进行了优选,结果表明球型模型拟合效果最好。针对序贯模拟和克里格品位估值效果进行了分析,结果显示:序贯高斯模拟结果在品位分布形态上更接近样品品位分布形态,其平滑效应更小;克里格方法估计与序贯高斯模拟方法相比仅在品位均值方面更接近样本品位均值。因此,认为序贯高斯模拟方法可以更好地刻画矿体内品位分布状态。