角闪石族和辉石族矿物的系统矿物学分类命名

角闪石族和辉石族矿物是链状硅酸盐矿物的重要组成部分,它们中的许多矿物种属于造岩矿物和/或工业矿物,具有重要的成因矿物研究意义和工业应用开发价值。国内学者对它们的分类命名和基本系统认识主要源自于王璞等(1984)编著的《系统矿物学》。随着科学技术发展和矿物学研究的不断深入,原有的矿物基础资料和分类命名都在不断更新与完善,迄今已有专业学术机构和学者在不同年代陆续发表了不同版本对该两类矿物的修订或修改意见,但一直没有统一整合,导致在涉及该两类矿物的应用研究中,在分类命名上与国际标准不统一。根据本课题组在国家公益性行业科研专项项目(新编《系统矿物学》)所承担的研究任务和当前国内外研究进展,本文系统归纳、梳理并综述了角闪石族和辉石族矿物的分类方案和命名原则,使分类命名统一标准、原则和认识并与国际接轨,这有利于该两类矿物的理论研究与开发应用,更好地支撑地质学及相关学科的研究与发展。     

浅谈地质资料管理的几个问题

国务院颁布的《地质资料管理条例》已于2002年7月1日在全国实施，《条例》以法规的形式颁布，显示出新时期地质资料的特点，即地质资料管理由以往单纯强调成果地质资料汇交，向统一汇交、公开利用、权益保护多领域职责转变。在统一汇交方面，《条例》规定了地质资料汇交由国务院和省（自治区、直辖市）人民政府地质矿产主管部门实行两级管理。     

Some mineralogical applications of synchrotron radiation

Synchrotron radiation offers several advantages over the conventional X-ray sources, among which the most important are its high intensity, broad spectral range and natural collimation. Among the numerous techniques which have been recently developed we present a review of the results concerning more specifically mineralogical systems: X-ray absorption spectroscopy concerning high-resolution edge spectra and Extended X-ray absorption fine structure (EXAFS), X-ray diffraction under high P-high T conditions, small-angle scattering, X-ray microanalysis and X-ray topography. For each technique the basic principles are described together with the experimental devices used, before mineralogical examples are given. Two main applications may be pointed out: chemical and structural characterization of disordered systems and kinetic studies (phase transitions and evolution). Many other techniques (photoelectron spectroscopy, X-ray fluorescence analysis ...) which are actually under development as a result of the rapid increase of the use of storage rings are not covered in the present review but will possibly also be used in the near future in Earth Sciences.     

Radioactivity dosage evaluation of Brazilian ornamental granitic rocks based on chemical data, with mineralogical and lithological characterization

One hundred samples of granitic rock were collected from granite traders in Belo Horizonte. Autoradiography, optical microscopy, diffractometry, and chemical analysis (X-ray spectrometry, X-ray fluorescence, neutron activation, gravimetry, and electron probe microanalysis) were used to determine the mineral assemblages and lithotypes. Autoradiographic results for several samples showed the presence of monazite, allanite, and zircon. Chemical analysis revealed uranium concentrations ≤30 ppm and thorium ≤130 ppm. Higher concentrations generally correlated with high concentrations of light rare earths in silica-rich rocks of granitic composition. Calculations were made of radioactive doses for samples, of floor tiles in a standard room, with total concentration of uranium and thorium greater than 60 ppm. On the basis of calculations of ²³² Th, ⁴⁰ K, and ²²⁶ Ra from analysis of Th, K, and U, the doses calculated were between 0.11 and 0.34 mSv/year, which are much lower than the acceptable international exposure standard of 1.0 mSv/year.     

Quantitative mineralogical and chemical assessment of the Nkout iron ore deposit,Southern Cameroon

The Nkout deposit is part of an emerging iron ore province in West and Central Africa. The deposit is an oxide facies iron formation comprising fresh magnetite banded iron formation (BIF) at depth, which weathers and oxidises towards the surface forming caps of high grade hematite/martite–goethite ores. The mineral species, compositions, mineral associations, and liberation have been studied using automated mineralogy (QEMSCAN^®) combined with whole rock geochemistry, mineral chemistry and mineralogical techniques. Drill cores (saprolitic, lateritic, BIF), grab and outcrop samples were studied and divided into 4 main groups based on whole rock Fe content and a weathering index. The groups are; enriched material (EM), weathered magnetite itabirite (WMI), transitional magnetite itabirite (TMI) and magnetite itabirite (MI). The main iron minerals are the iron oxides (magnetite, hematite, and goethite) and chamosite. The iron oxides are closely associated in the high grade cap and liberation of them individually is poor. Liberation increases when they are grouped together as iron oxides. Chamosite significantly lowers the liberation of the iron oxides. Automated mineralogy by QEMSCAN^® (or other similar techniques) can distinguish between Fe oxides if set up and calibrated carefully using the backscattered electron signal. Electron beam techniques have the advantage over other quantitative mineralogy techniques of being able to determine mineral chemical variants of ore and gangue minerals, although reflected light optical microscopy remains the most sensitive method of distinguishing closely related iron oxide minerals. Both optical and electron beam automated mineralogical methods have distinct advantages over quantitative XRD in that they can determine mineral associations, liberation, amorphous phases and trace phases.     

A model of Earth’s deep interior basedon mineralogical data

Summary ?We describe here a model of formation of the core and the early history of Earth based on recent experimental mineralogical data. In a nebular setting, where differentiated planetesimals with their iron cores were plentiful, hot condensing solids mixed with the planetesimal irons and formed the solid proto-core (Fe-Ni-S-C). FeO from unmixing in magnesiowustite and from a dissociation of perovskite in the newly accreted mantle concentrated at the core-mantle interface and reacted with the nascent core. The interface grew to form the liquid core (Fe-Ni-O-S-C) at the expense of the solid proto-core and the formation of much of the outer core was complete within the first 500 million years. The model is consistent with geochemical data and has important implications for the dynamics of the inner core.

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Zusammenfassung ?Das Innere der Erde: Ein Modell basierend auf mineralogischen Daten Wir pr?sentieren ein Modell zur Bildung des Erdkerns und der frühen Geschichte der Erde, das auf neuen experimentellen mineralogischen Daten basiert. In einem nebularen System, in dem differenzierte Planetesimals mit Eisenkernen sehr h?ufig waren, mischten sich kondensierte Festk?rper mit dem Eisen der Planetesimals, um einen festen Protokern (Fe-Ni-S-C) zu formen. FeO, das aus Magnesiowüstit entmischte und durch Dissoziation aus Perovskit im Mantel entstand, konzentrierte sich in der Kern – Mantel – Grenzzone und reagierte mit dem neugebildeten Kern. Diese Grenzzone wuchs und es entstand ein flüssiger (Fe-Mi-O-S-C) Kern auf Kosten des festen Protokerns. Die Bildung des ?u?eren Kerns war innerhalb der ersten 500 Millionen Jahre abgeschlossen. Dieses Modell ist mit geochemischen Daten konsistent und hat wichtige Auswirkungen auf die Dynamik des inneren Kerns.

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Received February 9, 1999;/revised version accepted April 9, 1999     

Comparison of color, chemical and mineralogical compositions of mine drainage sediments to pigment

 Forty-three untreated and actively and passively (wetland) treated coal mine drainage sediments and five yellow-red pigments were characterized using X-ray fluorescence, fusion-inductively coupled plasma atomic emission spectroscopy, X-ray diffraction, and tristimulus colorimeter. Primary crystalline iron-bearing phases were goethite and lepidocrocite, and iron phases converted to hematite upon heating. Quartz was nearly ubiquitous except for synthetic pigments. Gypsum, bassinite, calcite, and ettringite were found in active treatment sediments. Iron concentrations from highest to lowest were synthetic pigment>wetland sediment>natural pigment>active treatment (untreated sediments varied more widely), and manganese was highest in actively treated sediments. Loss on ignition was highest for passively treated sediments. No clear trends were observed between quantified color parameters (L*, a*, b*, and Redness Index) and chemical compositions. Because sediments from passive treatment are similar in chemistry, mineralogy, and color to natural pigments, the mine drainage sediments may be an untapped resource for pigment. Received: 29 December 1997 · Accepted: 11 May 1998     

Lack of relationship between Al ages of chondrules and their mineralogical and chemical compositions

Previous studies have suggested the existence of a correlation between ²⁶Al relative crystallisation ages and mineralogical and bulk chemical compositions of ferromagnesian chondrules from the Bishunpur and Semarkona unequilibrated ordinary (0120 and 0150). However, because the precision in ²⁶Al ages was moderate, these correlations are questionable. Here, we report mineralogical and chemical compositions of 14 ferromagnesian chondrules from Semarkona for which precise ²⁶Al ages were previously obtained (Villeneuve et al., 2009). We find global correlation of ²⁶Al ages neither with bulk chemical composition of chondrules, nor with the different types of ferromagnesian chondrules, i.e. PO, POP and PP. This indicates that if some kind of correlations between chemical compositions of chondrules and their ages of formation exists, they do not exist at timescales that can be measured with the ²⁶Al-²⁶Mg systematics but presumably at much shorter timescales.     

A preliminary study on mineralogical and chemical compositions of some chondrites falling in China

Samples are available from 37 stony meteorites falling in China. Twenty-two chondrites are examined in terms of chemical and mineral compositions, cosmogenic nuclides, formation and exposure ages, impact effect and chondrule textures. On the basis of chemical-petrologic features these chondrites are classified asE ₄ (Qingzhen),H ₅ (Jilin, Changde, Shuangyang, Anlong, Xinyi and Yangjang),L ₆ (Renqiu, Junan, Heze, Rugao and Nei Monggol) andLL ₆ (Dongtai). E ₄ is characterized by high iron and sulfur, with the former occurring mainly as Fe^o and FeS. FromH ₅ throughH ₆ toLL ₆, iron and nickel decrease gradually while FeO and the ratio of Fe silicate to total iron increase gradually. indicating a general increase in the orderE-H-L-LL in the degree of oxidation at the time of formation. E ₄ consists mainly of enstatite and, to much less extent, free SiO₂ but olivine is hardly to be found. The olivine proportions amount to 29.07, 41.98 and 51.36 percent inH ₅,L ₆ andLL ₆ respectively, with Fa increasing from 17 to 27 percent. Recrystallization has been noticed to different degrees inH ₄,H ₅,L ₆ andLL ₆ chondrites. The extent to which the original structure disappears and the boundaries of chondrules become indistinct decreases from type 6 through type 5 to type 4, reflecting different degrees of thermal metamorphism. Major minerals in the meteorites all exhibit signs of low to medium shock metamorphism. Specific activity, depth effect and orbit effect are also measured on some chondrites that have fallen in recent years and some new information has been obtained with respect to the orbit and source region for meteorite parent bodies in space. This results show that the environment of formation ofE group may be nearer to Mars than that ofO group. Each chemical group of chondrites has its own evolutionary history, and chondritets of different chemical groups may have originated from parent bodies of different compositions. Or owing to the differentiation caused by thermal melamorphism, various kinds of meteorites may be derived from a common parent body. From this argument it is suggested that five stages may be recognized during the formation process of chondrites.     

日喀则蛇绿岩研究中的几个问题

日喀则蛇绿岩是中国最著名的蛇绿岩,但是,许多问题存在争论,许多现象没有搞清楚。文中讨论了日喀则蛇绿岩中一些重要的现象以及对目前发现的许多矛盾如何考虑的问题。例如,(1)日喀则蛇绿岩中是否存在席状岩墙群?是否存在席状岩床群?本文认为,席状岩墙群应当是存在的,因为有不对称冷凝边出现。而席状岩床群可能是有问题的,岩床作为侵入体可以出现在许多地方,但是,蛇绿岩中不可能出现席状岩床群,尤其还把它作为蛇绿岩岩石组合的一个单元。笔者认为,所谓的席状岩床群可能是席状岩流群,它不是一个独立的单元,是玄武岩单元下部的成员。(2)日喀则蛇绿岩是否统统是蛇绿岩是一个需要考虑的问题,雅鲁藏布江东西两段出现的岩石组合及其产出背景与日喀则地区的蛇绿岩明显不同,其中有些可能未必是蛇绿岩。(3)自1972年彭罗斯会议以来,蛇绿岩研究发展到现在,可能已经进入了一个关键时期。文中回顾了蛇绿岩的定义及其构造意义,指出1972年彭罗斯会议关于蛇绿岩的定义仍然是适用的。蛇绿岩可以概括为洋壳+地幔,这个洋壳来自板块扩张脊,是年轻的;这个地幔是大洋岩石圈地幔,也可能保留有古老岩石圈地幔的印记。蛇绿岩产于板块扩张脊,这是蛇绿岩构造含义的唯一解,蛇绿岩不存在多解性。(4)日喀则蛇绿岩的许多基本观点主要是法国学者提出来的,如关于岩床群的见解,慢速扩张的见解等。但是,上述见解是否都是对的是需要思考的。日喀则蛇绿岩具有得天独厚的条件,我们应当很好利用这个条件,努力把我们的研究做好,为全球蛇绿岩研究贡献我们的一份力量。     

Some problems with the cumulus theory

There are a number of features in layered intrusions which do not appear to be consistent with the cumulus theory. The most important of these are: (1) Rhythmic layering in plagioclase-pyroxene cumulates from some intrusions (e.g. Jimberlana and Stillwater) may be inverted with the light plagioclase-rich cumulates at the base of the layer and heavy pyroxene-rich cumulates at the top. (2) Hydraulic sorting in rhythmically layered cumulates is often poor, suggesting that chemical and not mechanical processes control the distribution of minerals in this type of layered sequence. (3) The textures of cumulates from the steeply dipping marginal zone of Jimberlana, which cannot have formed by gravity settling, are indistinguishable from those found in the flatly dipping central layers of the intrusion. Similarly, it is difficult to explain the cumulate textures in the ‘overturned’ marginal layered series of Jimberlana. (4) Igneous layering, including cross-bedding, graded bedding and trough banding, has been described in layered sequences with near-vertical primary dips. (5) Calculations and experiments with a centrifuge furnace suggest that plagioclase cannot sink in Fe-rich tholeiitic liquids. (6) The settling of crystals as individual grains assumes that nucleation is homogeneous. This is unlikely.

It is probable that heterogeneous and self-nucleation are the dominant nucleation mechanisms during the formation of cumulates. This gives rise to two possibilities. Firstly, that most grains nucleate against pre-existing settling crystals to form composite grains which gravitate to the floor of the chamber. Secondly, that the cumulus grains nucleate in situ at the temporary floor of the magma chamber.     

叶碲铋矿研究中存在问题分析

叶碲铋矿最初定名为wehrlite，结构式为Bi2 xTe3-x，后于1982年改名为pilsenite，结构式相应改为Bi4Te3。楚碲铋矿(BiTe)的成分介于原叶碲铋矿的成分范围之内。有些研究者仍用原成分确定叶碲铋矿或把楚碲铋矿当作叶碲铋矿，本文旨在提醒研究者注意，避免误用。     

埃达克岩研究的几个问题

在简略分析中国埃达克岩研究情况的基础上,讨论了新近在有关埃达克岩研究方面取得的主要进展,探讨了先前埃达克岩研究中很少或者没有注意到的特殊的地球动力学意义。强调O型埃达克岩的出现标志着大洋萎缩消减的开始,C型埃达克岩的出现则暗示地壳在此之前就已经加厚,同时认为要解决埃达克岩研究中存在的一些问题,在很大程度上还有赖于青藏高原的埃达克岩研究。     

Some problems of slope development

Slopes are the fundamental unit of the physiographic landscape. Yet the reasons for variations in their morphology and inferred mode of development are not well understood. The problem is complex, but the slope budget, which results primarily from the interplay of climatically induced factors and structure is significant: where the erosion of the upper slope elements surpasses that on the lower, parallel retreat prevails, but when the reverse is the case, slope decline is dominant. Complications are introduced by such factors as climatic change and fluctuations of baselevel, both local and general. But structural factors can and do override all others.

A knowledge of geomorphic history, and of processes and their effectiveness under various circumstances, in advance of that usually at our disposal at present is necessary before slopes can satisfactorily be analysed. It appears unlikely that there is a universal law of slope development..     

开合构造研究中的几个问题

开合构造是中国学者提出来的一种大地构造观点,强调开裂运动和聚合运动是统一地球动力体系中的2种基本运动形式。开合构造是从开与合相互对立、相互依存、相互转化来研究区域地质特征和大地构造演化的。本文简介了开合构造中的几个问题:开合构造是一种新的大地构造观点;开合运动是地质运动的高级形式;开合类型是固定论和活动论的对立统一;开、合、剪之间是辩证关系;开合构造要冲出国门走向世界。     

工程地质学面临的几个困难

本文就岩土体的不连续性问题,岩体变形破坏的微观机制问题及时空问题,岩体的大变形与小变形问题,进行了讨论。     

The physical, chemical and mineralogical properties of three cemented layers within sulfide-bearing mine tailings

The oxidation and subsequent dissolution of sulfide minerals within mine tailings impoundments releases H⁺, Fe(II), SO₄ and trace elements to the tailings pore water. Subsequent pH-buffering and hydrolysis reactions result in the precipitation of secondary phases such as gypsum, goethite and jarosite. In areas of intense precipitation, cemented layers or “hardpans” often form within the shallow tailings. Three cemented layers within pyrrhotite-bearing mine tailings at the Fault Lake, Nickel Rim and East Mine impoundments located near Sudbury, Canada, were examined. The location of the three cemented layers within the tailings stratigraphy varies as does their location relative to the water table. The morphology, mineralogy and chemical composition of the cemented layers also vary between sites. The bulk density within the three cemented layers all showed an increase relative to the surrounding uncemented tailings ranging from 9% to 29%. The porosity of each cemented layer decreased relative to the surrounding uncemented tailings ranging from an 8% to 18% decrease. The cemented layers also showed relative enrichment of total sulfur, carbon and trace elements relative to the surrounding uncemented tailings. Arsenic concentrations showed an enrichment in the cemented layers of up to 132%, Cd up to 99%, Co up to 84%, Cu up to 144%, Ni up to 693% and Zn up to 145% relative to the surrounding uncemented tailings. All the cemented layers studied show an evolution of the secondary phases with time from a gypsum–jarosite-based cement to a goethite-rich cement. The formation of these layers could potentially have a significant effect on the environmental impacts of sulfide-bearing mine waste.