覆盖区多目标地球化学调查数据应用前景浅析--以江苏省国土生态地球化学调查有关成果为例

多目标地球化学调查是一项基础性、公益性地质调查工作，江苏省的多目标地球化学调查是全国实施此项工程的重要组成部分，可作为覆盖区开展此项工作的一个代表。本文简介了江苏省开展多目标地球化学调查工作的基本情况，用具体实例说明了多目标地球化学调查数据在示踪人类活动对自然土壤环境的影响、研究区域地质背景对土壤环境的制约作用、开展局部土壤生态环境安全预警、指导开发利用局部富Se土壤资源等方面的初步应用效果，对江苏省多目标地球化学调查资料的应用前景及如何进一步利用好多目标地球化学调查数据的相关问题进行了专门探讨，并提出了有关建议。     

内蒙古东乌旗阿尔哈达银铅锌矿区地质、物化探特征及其找矿意义

在内蒙古东乌旗阿尔哈达矿区通过地质、物、化探综合手段进行找矿,取得了良好效果,现已发现3个成矿带,仅在Ⅰ号矿带就发现规模不等的矿体近20个,初步概算银、铅锌资源量已达到中型矿床规模.该矿区的找矿经验对在草原覆盖区开展找矿工作具有指导意义.     

青海省冷湖小赛什腾铜矿岩屑地球化学特征

文章总结了小赛什腾铜矿的地球化学特征,认为闪长岩体本身含铜,岩体内存在着多期多阶段矿化叠加及多种矿化类型,平面上元素分带明显.指出了Cu,Au,Mo异常叠合部位仍是重点找矿地段.     

Comparison of Linear Regression Models for Quantitative Geochemical Analysis: An Example Using X-Ray Fluorescence Spectrometry

This paper presents statistical aspects related to the calibration process and a comparison of different regression approaches of relevance to almost all analytical techniques. The models for ordinary least-squares (OLS), weighted least-squares (WLS), and maximum likelihood fitting (MLF) were evaluated and, as a case study, X-ray fluorescence (XRF) calibration curves for major elements in geochemical reference materials were used. The results showed that WLS and MLF models were statistically more consistent in comparison with the usually applied OLS approach. The use of uncertainty on independent and dependent variables during the calibration process and the calculation of final uncertainty on individual results using error propagation equations are the novel aspects of our work.     

Viscous Energy Dissipation and Strain Partitioning in Partially Molten Rocks

We develop a steady-state fluid-mechanical analysis describingthe effect of strain partitioning on viscous energy dissipation.As observed in experimental studies of shear deformation ofpartially molten rocks, strain partitions when melt segregatesbecause viscosity is reduced in regions of elevated melt fraction.The equations derived here are based on parameters measuredin experiments, describing the evolution of melt distributionand rheological properties. We find that the dissipation dependsstrongly on the configuration of the melt-rich network of shearzones, including the average angle, volume fraction of meltand amplification of strain rate in the melt-rich bands. Minimain energy dissipation as a function of band angle develop, correspondingto configurations of melt networks that minimize the differencein mean stress between the band and the non-band regions. Wepropose that the organization of band networks occurs by theinterplay between strain localization and viscosity variationsassociated with melt segregation. The band networks maintaina steady-state angle during shear by continuously pumping meltthrough the network. The development of strain partitioningin melt-rich networks will modify the energetics of meltingand melt transport by efficiently extracting melt and reducingeffective viscosity. KEY WORDS: melt transport; rheology; self-organization; strain localization; strain partitioning     

Mantle Preconditioning by Melt Extraction during Flow: Theory and Petrogenetic Implications

Mantle preconditioning may be defined as the extraction of smallmelt fractions from mantle asthenosphere during its flow tothe site of magma generation. Equations may be written for mantlepreconditioning, assuming that the mantle comprises enriched‘plums’ in a depleted matrix. The equations takeinto account variations in mass fraction of plums, the relativerate of melting of plums and matrix, the temperature and pressureof melt extraction, the mass fraction of melt extracted, theextent of chemical exchange between plums and matrix, and theefficiency of melt extraction. Monitoring mineralogical changesand variations in partition coefficients along the inferredP–T–t path of the mantle asthenosphere allows theequations to be correctly applied to the conditions under whichmelt extraction takes place. Numerical experiments demonstratethe influence of petrogenetic variables on the shape of meltextraction trajectories and provide new criteria for distinguishingbetween melt extraction and mixing as the cause of regionalgeochemical gradients. Representative examples of arc–back-arcsystems (Scotia), continental break-up (Afar) and plume–ridgeinteraction (Azores) indicate that the compositions of the mantlesources of mid-ocean ridge basalts and island arc basalts maybe determined, at least in part, by the melt extraction historiesof their asthenospheric sources. KEY WORDS: geochemical modelling; mantle flow; isotope ratios; trace elements     

内蒙古东乌旗阿尔哈达银铅锌矿区地质、物化探特征及其找矿意义

在内蒙古东乌旗阿尔哈达矿区通过地质、物、化探综合手段进行找矿，取得了良好效果，现已发现3个成矿带，仅在Ⅰ号矿带就发现规模不等的矿体近20个，初步概算银、铅锌资源量已达到中型矿床规模。该矿区的找矿经验对在草原覆盖区开展找矿工作具有指导意义。     

内蒙古东乌旗达赛脱铅锌矿的控矿构造

通过对东乌旗区域构造及达赛脱铅锌矿区构造带的分析，阐明了NEE向构造为达赛脱铅锌矿区的主要控矿构造。     

浙江省龙游志棠地区硒的地球化学研究

通过对龙游富硒区硒的分布、迁移、富集特征和地质背景进行地球化学调查,确定硒来源自寒武纪荷塘组含煤岩系.同时对区内硒的生态环境效应研究表明,长期摄人适量的硒对人体健康具有重要作用.     

FORMATION OF GOLD-BEARING HYDROFRACTURING BRECCIA BODIES IN TECTONIC LENSES： A CASE STUDY ON SHUANGWANG GOLD DEPOSIT, SHAANXI, CHINA

1 Introduction Hydrofracturing is possibly an important fracture behavior within the whole lithospheric crust, many geologists have noticed and carried out study on hydrofracturing in the fluid-rock systems (e.g., Phillips, 1972; Sibson, 1986; Fyfe, 1987; Svyatoslav and Kirill, 1993; Cox, 1995; Nakashima and Toriumi, 1996; James et al., 2000; Agust et al., 2002). Hydrofracturing phenomena are universally existent in the active structural belts, nonlinear tension vein systems in metamorphi…