砷铅铁矾的矿物学特征及其地质环境意义

砷铅铁矾一般产出于含砷硫化物矿床氧化带铁帽中，常见与之共生的矿物有臭葱石、砷铅石、砷铅铁石、乳砷铅铜石等砷酸盐类矿物。该矿物呈菱面体晶体，常呈假立方体状、粒状和球粒状。暗黄绿色。Hm=3．5，Hv=375kg／mm^2，Dm=4。广西平桂矿区产出的砷铅铁矾的化学成份W(B)／％为：PbO31．18，Fe2O3 31．38，As2O5 18．87，SO3 10．84，H2O 8，据此计算的矿物分子式为：Pb0.99Fe2.80(AsO4)1.17(SO4)0．96(OH)6．24。广西德保矿区产出的含铜较高的铜砷铅铁矾(?)的平均化学成份．W(B)／％为：PbO 31．72，Fe2O3 29．21，CuO 7．96，As2O5 14．84，SO3 9．88，H2O 8，据此计算的矿物分子式为：Pb0.99Fe2.61Cu0.69(AsO4)0.89(SO4)0.86o(OH)7.20砷铅铁矾(德保)的粉晶X射线分析主要衍射强线有：5．90(9)，3．65(5)，3．07(10)，2．29(8)，1．976(6)。晶胞参数为：a0=0．732nm，c0=1．702nm，Z=3。三方晶系，空间群为R3m。红外吸收光谱分析显示有波数／cm^-1为3475，3402，3212，1639，993，919，825，763，549，535．428等吸收带。差热分析显示有460C，770C和910C3个明显的吸热谷。     

广西德保铜锡矿床氧化带产出的砷酸盐矿物

广西德保矿区是我国最重要的砷酸盐矿物产区，已发现有17种砷酸盐矿物，其中钡毒铁石，砷铜矾等12种为在国内首次发现，文中提供了其中一些重要新发现矿物较详细的矿物学数据，初步阐述了该类矿物在德保铜锡矿床氧化带的共生组合特性，指出该类矿物是矽卡岩型铜－锡矿床以及铜铅锌等多金属硫化物矿床的重要找矿标志。     

对铅圆柱锡矿的重新认识

铅圆柱锡矿(potosiite)是1981年在玻利维亚的锡矿床中发现的,沃尔夫等人测定了它的化学成份和X射线粉晶衍射数据,作为新矿物列入JCPDS卡片。近年来作者在工作中发现,实际上该矿物旱在1972年就被我国地质工作者在广西大厂的锡石硫化物矿床中采集,由于该矿物的物理性质与辉锑锡铅矿的物理性质极为相似,以及限于当时的实验条件而误定名为辉锑锡铅矿。为便于今后的工作,作者认为育必要对铅圆柱锡矿和辉锑锡铅矿进行重新认识。     

在广西德保发现的砷铜铅石

砷铜铅石(Duftite)在1920年首次发现于西南非,其后在墨西哥、美国等地亦有发现。该矿物在我国仅见有简单的报导。1984年笔者在广西德保矿区发现了该种矿物,并进行了矿物学的研究。 一、产状及其共(伴)生矿物 广西德保矿床属矽卡岩型铜—锡矿床,该矿床的铁帽氧化带比较发育,并且在氧化带中发育有多种砷酸盐矿物。砷铜铅石即产在氧化铜矿石中,与孔雀石、硅孔雀石呈互层的皮壳状产出,或产于臭葱石和砷菱铅矾的集合体的晶洞中。共(伴)生矿物有乳砷铅铜石、砷     

广西德保铜-锡矿床氧化带砷酸盐矿物组合特征及其成因的初步研究

笔者通过对广西德保铜-锡矿床氧化带次生矿物的研究,发现了14种砷酸盐矿物,其中多数为国内首次发现。这些砷酸盐矿物主要是铜的砷酸盐矿物,次为铜和铅的砷酸盐矿物,还有少量铁、铅、钡的砷酸盐矿物。根据这些矿物的共生组合关系,把它们划分为如下组合系列:(1)光线石-橄榄铜矿-墨绿砷铜石-羟砷铜石-德保石-硅砷铜石组合;(2)臭葱石-砷铅铁矿-砷菱铅矾-乳砷铅铜石-砷铜铅石组合;(3)臭葱石-含钡毒铁石-绿砷钡铁石组合。砷酸盐矿物一般形成于温湿多雨的热带—亚热带、pH为6—8,并有大量毒砂和碳酸盐岩存在的硫化物矿床氧化带中。     

在我国南方矽卡岩锡矿床氧化带中新发现十六种砷酸盐矿物

矽卡岩锡矿床往往发育有铜、锌、铅硫化物,並常以含多量的毒砂为特征。华南地处亚热带,温暖潮湿多雨的气候条件有利于硫化物的氧化並形成盐类矿物。过去对硫化矿床氧化带的次生富集矿物及矾类矿物研究较多,对砷酸盐矿物的研究较少,尤其对氧化铜矿石和褐铁矿石中砷的赋存状态研究更少。由于矿石中砷的赋存状态不明而使许多氧化铜矿石和褐铁矿石无法利用。经过几年的努力,我们在矽卡岩锡矿床氧化带共发现十六种砷酸盐矿物,其     

砷铝铁石的发现及其初步研究

1986年,在广西德保铜锡矿床氧化带铁帽中发现有砷铝铁石,针柱状晶呈晶簇状产出。鲜红色至褐红色,硬度HM＝3．5,DX＝5．34,折光率大于2。五个颗粒电子探针分析平均化学成分（％）为Fe2O320．77．PbO38．29,As2O5;36．64．CaO0．24．Al2O30．43,SiO20．30,H2O＋末分析（以2．85％计）计算出分子式：Pb1.11Fe1.69Al0.05Ca0.03[（AsO4）2．07（SiO4）0.03]2.10（OH）2.05,粉晶X射线分析主要衍射线（nm）有：0．324（10）（202）,0．295（8）（15）,0.305（7）（40）,0256（7）（242）,0.458（6）（211）,0．418（5）（131）,0．356（5）（311）,0.273（5）（251）,斜方晶系．计算出晶胞参数a＝1．2281nm,b＝1．6657nm,c＝0．7663nm,Z＝8。红外吸收光谱分析显示有波数为3448,3405,1638,1082,864,808,758,459（cm-1）等吸收带。     

个旧土状赤铁矿型锡矿成因的商榷

土状赤铁矿型锡矿,系指个旧矿区内以樱红色土状赤铁矿为主的锡矿床,是解放前、后的主要开采对象.这种矿石致密,镜下只见锡石;高倍镜下也未见到赤铁矿,X射线分析定名为赤铁矿.以往,曾把本区原生锡矿床中的热液型矿床,划分为夕卡岩-硫化物矿床和层间氧化矿床两大类(见表).后者又按其矿物组成划分为含有大量铅矿物的氧化矿床(习惯上称为铅-锡型或锡-铅型矿床)和土状赤铁矿型锡矿两类.夕卡岩-硫化物矿床产于接触带内,含有铁、铜、铅、铋、钼等矿物,无疑属热液型.氧化铅-锡型矿床,虽产于碳酸盐岩     

广西北部矽卡岩锡矿床氧化带中的砷酸盐矿物

过去对硫化矿床氧化带的次生富集矿物及钒类矿物研究较多,对砷酸盐矿物研究较少,尤其对氧化铜矿石和褐铁矿石中的砷赋存状态研究更少。经过几年的努力,我们在住北矽卡岩锡矿床氧化带中共发现16种砷酸盐矿物,其中一种定名为德保石(待审批的新矿物);一种是有疑义的矿物——硅砷铜石(?);其余为:光线石[Cu_3(AsO_4)(OH)_3]、橄榄铜矿[Cu_2(AsO_4)(OH)]、墨绿砷铜石[Cu_5(AsO_4)_2(OH)_4H_2O]、羟砷铜石[Cu_5(AsO_4)_2(OH)_4H_2O]、砷钙铜石[CaCu(AsO_4)     

一个新的铋亚碲酸盐矿物—平谷矿

平谷矿是在北京市平谷县一小型金矿氧化带中发现的一种新矿物。共生和伴生矿物有褐铁矿、孔雀石、磷氯铝矿、泡铋矿、自然金、银金矿、石英、方解石和白钨矿。通常呈粒状集合体出现，单体板柱状，极为细小（0．3～0．6μm），黄绿色，玻璃至金刚光泽。实测密度＝8．44g／cm3，计算密度8．64g／cm3。维氏硬度449～572kg／mm2，相当摩氏硬度5～6。反射率＝13．25％，折射率＞2．0，计算折射率为2．145，电子探针分析结果Bi2O379．56％、TeO220．17％，总和99．73wt％，化学式Bi5。8043Te2。1475O13理想式Bi6Te2O13。X射线粉晶分析主要强线3．146（100）（12）、2．841（80）（200）、2．694（20）（040）、1．695（20）（321）、1．956（10）（240）、1．631（10）（16），斜方品系，a＝0．5689（1），b＝1．0791、c＝0．5308（1）um，晶胞体积V＝0．3258um3，Z＝1。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

NONMETALS DEPOSITS

正20141520 Bo Ying(Key Laboratory of Metallogeny and Mineral Assessment,MLR,Beijing 100037,China);Liu Chenglin Saline Spring Hydrochemical Characteristics and Indicators for Potassium Exploration in Southwestern and Northern Tarim Basin,Xinjiang(Acta Geoscientica Sinica,ISSN1006-3021,CN11-3474/P,34(5),2013,p.594-602,5 illus.,3 tables,28 refs.)     

MATHEMATICAL GEOLOGY

正20141243Chen Ge(Hangzhou Research Institute of Petroleum Geology,PetroChina,Hangzhou 310023,China);Si Chunsong Study on Sedimentary Numerical Simulation Method of Fan Delta Sand Body(Journal of Geology,     

PROSPECTING EXPLORATION

正20142599Chen Sanming(Guangxi Key Laboratory of Concealed Deposits Exploration,Guilin University of Technology,Guilin541004,China);He Yuzhou Block Model and Reserves Estimation of Panzhihua Iron Deposit Based on 3D Geological Modeling(Journal of Guilin University of Technology,ISSN1674-9057,CN45-1375/N,33(4),2013,p.610-615,9illus.,1table,15refs.)     

STRUCTURAL GEOLOGY

正20140594 Bai Daoyuan(Hunan Institute of Geology Survey,Changsha 410016,China);Zhong Xiang Faults in the Jingzhou Basin and Their Tectonic Settings(Geotectonica et Metallogenia,ISSN1001-1552,CN44-1595/P,37(2),2013,p.173-183,6illus.,59refs.)Key words:basin evolution,tectonic setting,South China In the Upper Paleozoic and Jurassic se-     

STRUCTURAL GEOLOGY

正20141912Cao Hui(State Key Laboratory for Continental Tectonics and Dynamics,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)Gravitational Collapse and Folding during Orogenesis:A Comparative Study of FIA Trends and Fold Axial Plane Traces(Geology in China,ISSN1000-3657,CN11-1167/P,40(6),2013,p.1818-1828,9illus.,35refs.,with