海南岛第四纪玄武岩的红土化作用

我国海南岛北部广泛分布着第四纪玄武岩,其中喷出规模最大、分布面积最广的是早更新世玄武岩(Q₁),其上覆盖着一层较厚的红土风化壳,有的成为可供开采的铝土矿和褐铁矿。晚更新世玄武岩(Q₃)出露范围较小,地表亦多风化成红土,但发育较差。笔者研究的红土风化剖面便发育在早更新世橄榄玄武岩上(图1)。     

再论察尔汗盐湖矿床的构造演化

柴达木盆地察尔汗盐湖的成盐建造可分为:浅部构造层(Q₂—Q₄);中部构造层(R—Q₁);深部构造层(K以前)。其成盐作用可分为:泛湖阶段(Q₁);盐渍阶段(Q₂);盐沼阶段(Q₃);干盐湖阶段(Q₄)。从地层建造、变形特征、继承关系、富盐程度讨论了构造层次的生成关系。由成盐物质侧向补给的盐筛效应、垂向补给的构造膜效应讨论了构造的成盐规律,并确立了盐湖不完全对称地堑式的沉积模式。     

土耳其Nallihan黄土-古土壤岩石磁学特征及其环境意义

黄土广泛分布在东欧和西亚地区,但位于欧亚大陆连接地带的土耳其未见风积黄土的报道,本文对位于土耳其首都安卡拉西北的Nallihan新发现的黄土-古土壤剖面进行系统的环境磁学研究,结合粒度参数和稀土元素指标,讨论土耳其黄土的成因和磁化率变化机制.研究结果显示:土耳其Nallihan S0～L3黄土剖面与典型风积的西伯利亚和中国西峰黄土的粒度特征图形态相似4暗示它们的成因相似性;稀土分配模式与黄土高原黄土基本一致,为上地壳平均值,指示了风积黄土在搬运过程中经过充分混合,整个剖面上下稀土模式分配高度吻合,说明研究区黄土堆积期间物源区相对稳定.热磁和磁滞分析表明样品的主要载磁矿物是亚铁磁性矿物磁铁矿/磁赤铁矿.该剖面磁化率在古土壤获得高值,在黄土层获得低值,磁化率与成土作用和指示细颗粒磁性矿物贡献的xfd％、xARM正相关,说明成土作用生成的细颗粒亚铁磁性矿物是磁化率增强的主导因素,土耳其黄土剖面磁化率总体上低于中国黄土高原地区黄土.该黄土剖面中有一层古土壤层S2,其顶部覆盖一层砾石层,说明在该间冰期发生过洪水作用,将高坡风化的砾石层冲到土层中堆积下来,在该砾石层之下的古土壤层,磁化率降低,可能与该时期土壤层湿度大,形成湿润氧化环境,导致部分强磁性的超顺畅/稳定单畴(SP/SSD)颗粒磁性矿物转化为弱磁性矿物,使得磁化率降低.     

黄土地层中CaCO3含量变化与更新世气候旋迴

深海沉积物剖面中CaCO₃含量变化与气候变迁密切相关,冰期时的高,间冰期时的低。若大陆上黄土地层中CaCO₃含量变化也有类似的性质,就更有利于气候长期变迁的海—陆对比以及探讨气候变迁的原因。本文根据陕西洛川黄土地层剖面中110多块样品的分析资料,用相关分析和方差分析,考察CaCO₃含量与黄土、古土壤形成环境的关系,并用频谱分析初步探讨约70万年来气候变迁的周期以及气候变迁的海—陆对比等问题。     

硅藻蛋白石基多孔材料的制备及对有机污染物吸附和催化性能

<正>硅藻蛋白石是一种由硅藻生物的遗骸(壳体)经沉积、堆积而形成的天然矿物。其主要成分为无定形二氧化硅,在矿物学上属A型蛋白石(Opal-A)。硅藻蛋白石具有以大孔(50 nm)为主的天然大孔/介孔型结构和优异的物化性能,因此已被广泛用作吸附剂和催化剂载体。然而,硅藻蛋白石的比表面积较低,用作吸附剂时其吸附容量有限;另一方面,其表面富含硅羟基,亲水性较强,故对疏水性有机污染物的吸附能力较弱。为此,本研究拟通过制备硅藻蛋白石/MFI型沸石复合材料、硅藻蛋白石基多孔陶瓷/纳米沸     

利用硅藻土自身固体酸性及孔性制备载银多孔炭

<正>硅藻土是由硅藻生物遗骸沉积堆积而成的一种矿物集合体。其主要成分(即硅藻壳体)为无定形二氧化硅,在矿物学上属A型蛋白石。硅藻壳体的一个显著特性是:具有不同于沸石、粘土矿物等微孔型多孔矿物的天然大孔(孔径50     

锡铁山石的化学式再定义

利用电子探针能谱仪检查新矿物——锡铁山石的成分时,发现有相当含量的氯。因此,原来的化学式Fe³⁺(SO₄)(OH)·7H₂O应修改为Fe³⁺(SO₄)Cl·6H₂O。     

莱河矿(Fe0.52+Fe1.03+SiO4)的超结构

莱河矿于1976年在中国辽宁省的磁铁矿床中首次被发现,许多人对它进行过研究。该矿物为黑色、不透明,化学式为Fe_0.58²⁺Fe_1.0³⁺Mg_0.03Si_0.96O₄,虽然它的晶体结构近似于橄榄石,但已确定为单斜晶系,空间群为P2₁/b。本文作者利用X射线、电子探针、高分解能透过电子显微镜对该矿物进行了系统的研究,发现它具有假双晶、超结构和显微条纹结构。     

由BaSO4直接热分解制备用于同位素分析的SO2

硫同位素地质研究工作中,经常遇到的研究对象是硫酸盐矿物。如何把这些硫酸盐矿物转化为适于质谱测定硫同位素组成的SO₂气体,是我国硫同位素地质研究中急待建立的实验手段之一。 经典的方法中,可溶于水的硫酸盐,通常是先把它沉淀为BaSO₄,然后通过一系列的化学反应转化为SO₂。 七十年代初期,B.D.Holt等人提出直接加热分解BaSO₄制备SO₂的方法。     

白云鄂博的氟碳钡铈矿

氟碳钡铈矿(Cordylite)BaCe₂(CO₃)₃ F₂本世纪初首先发现于格陵兰纳尔萨尔苏克(Narssarssuk)的碱性正长伟晶岩脉中,与霓石、氟碳铈钙矿、柱星叶石和碳锶铈矿共生。1965年该矿物又发现于我国白云鄂博西矿区热液交代的元古代白云岩中。1975年,加拿大魁北克省圣赫莱山(Mont st. Hilaire,Quebec)的霞石正长岩中的伟晶岩脉中也发现了这一矿物,它与方沸石、霓石和钠闪石共生。     

东太平洋海盆内多金属结核中的铁矿物

东太平洋海盆内多金属结核中的铁矿物萧绪琦郭立鹤（中国地质科学院矿床地质研究所，北京１０００３７）１前言早在五十年代人们就已注意到，大洋多金属结核含铁量较高，由于结核中矿物颗粒细小，结晶程度低，使得铁矿物的确定很困难，通常称之为铁的氧化物和氢氧化物。在...     

大别山区石英质玉宝石矿物学特征研究

大别山区石英质玉属新近发现的一种石英质玉（简称＂大别山玉＂）,具色彩绚丽、质地细腻温润等特点。利用偏光显微镜、扫描电子显微镜、X射线粉末衍射、化学分析、红外光谱分析等方法,重点对＂大别山玉＂的矿物组成、化学成分、物理光学性质、微结构、红外吸收光谱等特征进行研究。结果表明,＂大别山玉＂具较典型的微粒-细粒结构,主要矿物为石英,含少量的绢云母、绿泥石、萤石、黄铁矿及其它粘土矿物等次要矿物,实属石英质玉;其化学成分相对较纯,主成分为SiO2,含少量的Al2O3,CaO,MgO,Fe2O3,FeO,K2O等;其红外反射光谱以Si—O非对称伸缩振动致特征的1177,1104 cm-1谱带、Si—O—Si对称伸缩振动致800,781cm-1分裂谱带以及由Si—O弯曲振动致492 cm-1较强谱带和542 cm-1弱谱带为特征。同时,还对＂大别山玉＂的结晶度及水的赋存状态一并给予了探讨。     

贵州松桃下寒武统九门冲组钼钒矿的赋存状态初步研究

研究工作主要以显微镜下光薄片研究鉴定为主,配合进行化学分析浸取试验以及电子探针定性、定量分析二次电子像、成分像以及特征X射线像等测试工作,初步查明钼以胶状硫钼矿集合体产出,钒则主要以类质同像形式存在于粘土矿物水云母中。     

沉积火山角砾岩中的绿泥间蛭石及其形成条件

在松辽盆地白垩系含油地层中,首次发现了火山角砾岩沉积体,其粘土胶结物由单一的绿泥间蛭石组成。本文报道了对该矿物的X射线衍射、红外光谱、扫描电镜、化学组成及阳离子交换量的分析结果。分析了它的形成机制和具体条件,认为它是在成岩过程中,在富Mg和富Fe的条件下,由蒙脱石转化而来。     

陕西镇安丘岭,二台子金矿床富砷矿石中金的赋存状态

对丘岭、二台子微细浸染型金矿床中－高含金样品的光学、背散射电子、二次离子和高分辨透射电镜图象分析表明，金与砷具有显微尺度的强相关性。金和砷主要赋存于含砷黄铁矿增生体、毒砂和砷黝铜矿之中。已发现金一般呈微米级小圆球存在于含砷硫化物中。次显微金在高异常区的沉淀作用是如此之迅速，其以微细自然金颗粒存在于砷的硫化物中。     

Iron–bentonite interactions in the Kawasaki bentonite deposit,Zao area,Japan

Greenish veins occurring in brecciated bentonite were found in the Kawasaki bentonite deposit of the Zao region in Miyagi Prefecture, Japan. Their occurrence possibly indicates the interaction of bentonite with Fe-rich hydrothermal solutions. In order to prove the hypothesis and understand the long-term mineralogical and petrographic evolution of bentonite during such interactions, the greenish veins and the surrounding altered bentonite were analyzed using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe micro-analysis (EPMA), scanning transmission electron microscopy with energy dispersed spectroscopy (STEM-EDS) and micro X-ray absorption near-edge structure (XANES). The greenish veins resulting from hydrothermal solution are composed of mixed-layer minerals consisting of smectite and glauconite (glaucony), pyrite and opal. The occurrences indicate that glaucony and pyrite formed almost simultaneously from hydrothermal solution prior to opal precipitation. The mineral assemblages of the greenish veins and their surroundings indicate that the hydrothermal activity had most likely taken place at a temperature of less than 100 °C and that the pH and Eh conditions of the reacted solution were neutral to alkaline pH and reducing. The unaltered bentonite is composed mainly of Al smectite and opal. These minerals coexist as a mixture within the resolution level of the microprobe analyses. On the other hand, the bentonite in contact with the greenish veins consists of discrete opal grains and dioctahedral Al smectite containing Fe and was altered mineralogically and petrographically by the hydrothermal activity. Both the clay minerals and the opal were formed by dissolution and subsequent precipitation from the interaction of the original bentonite with the hydrothermal solution.     

The nature and origin of pigments in black opal from Lightning Ridge,New South Wales,Australia

Abstract

Black opal (opal-AG) owes its dark coloration to a fine-grained pigment commonly inferred to be mainly carbon, yet chemical compositions for black opals suggest there may be additional components. Here we search for such components in pigment concentrates prepared by dissolving black opal nodules (nobbies) from Lightning Ridge (NSW) in hydrofluoric acid, using electron microscopy (scanning electron microscopy, transmission electron microscopy), X-ray diffraction and laser-ablation ICP-MS. The results demonstrate the presence of sulfides—predominantly pyrite and chalcopyrite, with minor galena and Ti-oxide phases, as additional components of the pigment. ATR-FTIR analysis indicates the presence of C=O and C–H groups, consistent with an organic origin. Transmission electron microscopy images of pigment show variously deformed, originally spherical ～100?nm particles rich in sulfide and carbon, which are interpreted as thin coatings of pigment on now dissolved opaline silica spheres. Laser-ablation ICP-MS analysis identifies remnant silica in pigment concentrates, which may be interpreted as opaline silica surviving HF treatment protected as inclusions in sulfides. When examined within the context of petrographic observations from more than 1000 opal nodules (nobbies) at Lightning Ridge, these new results suggest that pigment carbon and sulfides in the nodules formed microbially under initially anoxic groundwater conditions, within pre-existing cavities concurrently being filled with silica sol ultimately derived from chemical weathering of feldspar-rich volcaniclastic sediment. Intensely black pigment layers observed at the floor of many nodules indicate settling of dark, high-density (sulfide–Ti-oxide-rich) pigment within cavities, with the implication that sulfate-reducing bacterial (SRB) activity commences early during the silica sol-gel ripening process. Microbial activity may persist until after the cavity has completely filled with the silica sol, as illustrated by abundant black opals with uniformly distributed pigment. Pigment formed at this stage may no longer be able to settle out within the ripening and increasingly viscous silica gel, thus forming pigmentation throughout the opal cavity. The existence of ‘amber’, pigment-poor opal with intensely black basal pigment layers is interpreted as signalling a lack of sulfate to sustain further SRB activity, or a change to more oxidising conditions, possibly related to interaction with surface waters within a downward-penetrating weathering front. A change in redox conditions would shut off activity of SRB and thus sulfide pigment production and allow development of aerobic microbial activity as described by others.     

Fractured surface of opal

Fine parallel lines were found on fractured surface of opal under reflection optical microscope. Study of replication electron microscopy of fractured surface with fine lines revealed three distinctive patterns. These were (1) lamellae with voids and without voids, (2) lamellae with two kinds of voids, and (3) lamellae without voids.     

云南个旧矿区斜方辉铅铋矿、硫锑铜银矿和含锌、银锑黝铜矿矿物学初步研究

作者在云南个旧矿区发现了斜方辉铅铋矿、硫锑铜银矿和含锌、银锑黝铜矿，并对矿物进行了显微鉴定，显微性质测定，电子探针分析以及线、面电子探针扫描分析等初步研究。     

安徽省笔架山绿松石矿床矿石矿物特征及矿床成因

安徽省马鞍山市境内分布一条典型的绿松石矿成矿带,其矿床成因一直存在争议。本次研究选取了该成矿带内笔架山绿松石矿床开展了详细的野外地质考察和室内观察,对绿松石矿石采用偏光显微镜、电子探针、扫描电镜（SEM）和ICP-MS等测试手段进行矿物学、岩石化学方面的分析与测试,并对与绿松石共生的黄铁矿进行了微量元素和δ³⁴S同位素测试。研究表明：绿松石矿床中矿石矿物为绿松石,并含少量石英、黄铁矿、高岭石、叶蜡石、褐铁矿和黄铁钾钒等矿物;绿松石为隐晶质集合体矿物,具变胶结构,SEM显示微晶集合体呈板片状平行或交错生长;与绿松石共生的黄铁矿具中低温热液成因的立方体、五角十二面体及其聚形晶形特征;在w（Ni）-w（Co）关系图中黄铁矿微量元素Co、Ni质量分数分布在岩浆和热液区;δ³⁴S_VCDT同位素（8.3‰~11.9‰）指示硫成矿物质来源于深部岩浆硫和沉积硫,成矿流体由大气降水和深部岩浆水混合而成。结合绿松石矿物组合、矿物生成顺序及共生黄铁矿成矿物质与成矿流体来源综合分析判断,该矿床为火山喷气活动形成的中低温热液蚀变交代（充填）型矿床。