Precambrian amphibolites and basic granulites of the south coast of Western Australia

Field relations and chemical variation trends suggest that amphibolite and basic granulite bands occurring throughout the Precambrian gneissic terrain of the south coast of Western Australia were derived from basic igneous rocks. It is not known whether the original rocks were mainly intrusive, extrusive, or pyroclastic, but occasional discordant contacts indicate that intrusive types are certainly represented.

The chemical affinities of the original magmas are not entirely clear. Present compositions suggest dominantly subalkaline affinities, although a significant proportion of the analised samples show some alkaline characteristics. Data for supposedly immobile elements (Ti, P, Zr, Nb, Y) show possible similarities to recent island‐arc and ocean‐floor basalts, but these are not sufficiently strong to permit any firm conclusions regarding the original tectonic environment of eruption or intrusion. This absence of clear chemical similarities of the amphibolites and basic granulites to basalts of any particular modern tectonic environment may suggest chemical modification during possible low‐temperature alteration (e.g. ocean‐floor or burial meta‐morphism) or subsequent high‐grade regional metamorphism and anatexis, or the inapplicability of currently recognised tectonomagmatic principles to the Precambrian.     

软弱砂岩骨料碾压混凝土的配制及其特性研究

在东南亚和我国西南地区由于缺乏合适的原材料,必须采用软弱骨料配制混凝土。以东南亚某工程现场的软弱砂岩为原材料,开展碾压混凝土配制和性能试验工作,探讨了该骨料配制碾压混凝土的可行性。采用软化系数为0.71的软弱砂岩,配制强度等级分别为C18020的二级配碾压混凝土和C1807.5的三级配碾压混凝土。结果表明,采用该砂岩骨料可以配制出满足强度要求的碾压混凝土,其用水量比常规骨料高15~20 kg/m3,拌和物密度和抗压弹模较低。其中,二级配碾压混凝土采用50%粉煤灰掺量、0.55水胶比;三级配碾压混凝土采用60%粉煤灰掺量、0.65水胶比。骨料抗碾压破碎模拟试验表明该骨料在碾压过程中破坏程度很低,说明采用该软弱骨料配制碾压混凝土具有可行性。     

鸡西盆地张新地区浅成侵入体对围岩有机质成熟度及变质程度的影响

利用鸡西盆地张新地区西风井揭示的连续剖面,采用镜质体反射率、伊利石结晶度分析测试方法对西风井浅成岩侵入后的上盘围岩有机质成熟度( Ro) 、变质程度进行研究,发现上盘围岩的镜质体反射率随远离辉绿玢岩体的距离增加而减少( 由2. 31%到0. 79%) ; 侵入体对上盘围岩有机质影响最大距离为129. 06 m,是岩体厚度的1. 2 倍; 伊利石结晶度数据显示围岩处于极低级变质程度,围岩的温度随远离辉绿玢岩体的距离增加而降低; 计算得出西风井城子河组地层最大埋藏温度为 259. 24℃,持续时间117. 7 a。最高温度及其持续时间决定围岩的变质程度,是围岩接触变质程度较低的原因。     

Grade-Tonnage, Ore Value-Tonnage, and Enrichment Ratio-Tonnage Models for Resource Assessment

I' Grade-tonnage diagrams are one of the most useful tools inthe resource assessment (e. g. St'nger, 1993). One' grade-tonnage diagram is well known as Laskys (1950) e\-7ation, whichdemonstrates the linear relation between average grade (x) andlOgarithms of cumulative ore tonnage (ac above a given gradex(0相似文献   

试论砂金矿勘探中小于可采宽度的矿体处理方法

本文以青海省某大型河谷型砂金矿特征为例,并结合其他已勘查过的河谷型砂金矿矿床特征分析,主张在砂金勘探中对小于可采宽度的矿体,除在施工中及时加密工程验证外,在储量计算时可用“边界米克值”衡量代替以“工业米克值”进行勘探线的矿与非矿判定,同时再配以“镶边”法处理较为合理。     

The Schmidt hammer in rock material characterization

The Schmidt hammer provides a quick and inexpensive measure of surface hardness that is widely used for estimating the mechanical properties of rock material. However, a number of issues such as hammer type, normalization of rebound values, specimen dimensions, surface smoothness, weathering and moisture content, and testing, data reduction and analysis procedures continue to influence the consistency and reliability of the Schmidt hammer test results. This paper presents: a) a critical review of these basic issues; and b) the results of tests conducted on granitic rocks of various weathering grades in the light of the conclusions of this review. It was found that a very good correlation exists between L and N hammer rebound values and that both hammers are fairly sensitive to the physical properties, particularly to dry density though less so to effective and total porosities. The N hammer, producing a lesser scatter in the data, proved to be more efficient than the L hammer in predicting uniaxial compressive strength and Young's modulus. The exponential form of the correlation curves was found to reflect microstructural changes during the course of weathering and the differences in the probing scales or mechanisms in the means of measuring these mechanical properties, and could be generalized to other crystalline igneous rocks. The possibility of predicting weathering grades from rebound values was also explored. The changes in the rebound values during multiple impacts at a given point produced a better indication of the weathering grade than a single impact value. It was concluded that increasing the impact energy and plunger tip diameter should significantly reduce the scatter in coarse-grained weathered rocks and hence improve the reliability of the Schmidt hammer as a rock material characterization tool.     

北京市生态农业地质及其前景

论述了北京市土壤元素含量和农作物优质高产与土壤环境中化学元素有密切的关系。提出了生态农业地质研究的目的、内容、方法、管理及其前景。     

GIS的空间分析技术在长春市大气环境功能分区中的应用

综合定量地进行了城市大气环境功能分区，运用地理信息系统中空间分析技术，将城市社会功能，气象特征以及环境现状叠加来定量划分城市大气环境功能区。提出了地理信息系统支持下的分区方法及其步骤。结果表明该方法能够定量划分城市大气环境的功能区。     

试论市场经济条件下圈定矿体的4项品位指标

阐述了在我国市场经济条件下，圈定矿体和划分不同储量／资源量的方法。提出了圈定矿体的4项品位指标的概念和确定方法。这4项品位指标依次为边界品位、边际品位、经济品位和矿床平均品位。利用前3项品位指标可以分别圈定矿体边界、次边际的资源量、边际经济的储量、经济储量。利用矿床平均品位可以衡量矿床是否具有投资价值。     

浅变质岩区非整体变形和滑动构造初探

在分析了陕西旬北浅变质沉积岩区、甘肃白银厂浅变质火山-沉积岩区的构造变形特征的基础上,得出了构造变形非整体性的认识,进而提出构造变形单元体的概念和划分依据,探讨了与非整体构造变形紧密相关的滑动构造的野外特征和鉴别方法.