福建寿山石“月尾紫”的矿物学特征研究

针对采自福建寿山地区的寿山石“月尾紫”品种进行了光学显微镜、X射线粉末衍射、拉曼光谱和扫描电子显微镜等仪器的系统分析测试。结果显示,“月尾紫”呈显微微晶结构,主要矿物组成为地开石,基质中可见大量的紫红色矿物赤铁矿。赤铁矿呈浸染状分布,是致使“月尾紫”整体呈现紫色的原因。由于赤铁矿本身色调和富集程度不同,导致“月尾紫”的紫色调有深有浅,同时由于赤铁矿浸染分布于地开石颗粒间,使得“月尾紫”呈现不透明状。扫描电子显微镜下可见地开石颗粒主要呈假六方板状,棱角清晰,厚度均匀,呈叠瓦状、书册状排列,能谱测试结果显示扫描电子显微镜下微米级球状矿物颗粒为二氧化硅。     

氧化铁矿物对五氯苯酚表面吸附实验及其反应模式

批量法实验研究表明,五氯苯酚 (PCP)在合成的针铁矿、纤铁矿和赤铁矿表面吸附的浓度等温线为饱和型特征,可用 Langmuir公式拟合,而 pH吸附等温线为峰型曲线,峰值在 pH≈ 5. 矿物表面化合态和 PCP溶液离子化合态分析与计算表明, PCP在氧化铁矿物表面存在两种吸附反应模式,即表面静电吸附反应和表面络合吸附反应,表面静电吸附反应常数比表面络合吸附反应常数高 1～ 2个数量级.并进一步从反应机制上证明了憎水型可离解有机化合物 (HIOCs)在矿物表面吸附的模式与趋向性.     

国外铁氧化物铜-金矿床的特征及其研究现状

铁氧化物铜-金矿床是一类具许多共同特征但成因联系不太密切的矿床类型，近来已成为国外铜-金勘探的主要矿床类型之一。该类矿床以矿石中含有大量的铁氧化物（磁铁矿或赤铁矿）且伴有很强的区域性钠（-钙）质蚀变为特征，可以产于元古代克拉通内或新生代大陆边缘岛弧环境，其周围具火成岩或含蒸发盐层，时空上与之有关的侵入岩为磁铁矿系列花岗岩，矿化主要产于近区域主断裂的羽状次级断裂中。部分该类矿床的形成与一定的主岩类型有关，而多数矿床可能由高盐度 H₂O-CO₂-盐混合流体的不混溶作用形成，且矿化通常与钾化有关。对成矿流体是主要来自岩浆还是受围岩控制尚有争论，成矿模式有蒸发盐来源模式、外来流体加热模式和岩浆-热液流体模式。但对部分该类矿床详细的流体包裹体和稳定同位素研究表明成矿流体主要源于岩浆。对该类矿床进行地球物理勘探需要考虑磁铁矿、硫化物和Cu-Au矿化之间的相互关系。在我国开展对该类矿床的研究将有益于发现新的铜资源基地。     

The hematite–goethite enhancement model of loess and an ‘irregular’ case from Paks,Hungary

On the basis of a key model of the appearance of hematite and goethite in some Chinese and European loess successions, paleosols generally contain higher proportions of hematite formed by pedogenic processes during warm and humid interglacials, while loess contains sedimentary goethite deposited during colder, glacial periods. Rock magnetic measurements were conducted on samples from Paks (Hungary) loess, revealing an anomalous case. Sediments were found to contain higher amounts of hematite and/or goethite, while the well‐developed paleosols were found to be lacking in hematite but had significant amounts of magnetite and maghemite. This observation demonstrates that the character of pedogenic magnetic mineral alteration and neoformation differs from the hematite/goethite model; the model is therefore not applicable to the Paks succession, possibly due to differences in the regional paleoclimate and pedogenic environment. The results indicate the existence of a further model, in which hematite formation is not significant in the course of pedogenesis.     

赤铁矿和氧化镁对养殖粪污厌氧发酵气体中H_2S的抑制

集约化畜禽养殖场厌氧发酵过程中产生的大量H2S具有潜在的危害。本文以某畜禽养殖场的新鲜猪粪为研究对象,通过添加不同比例的赤铁矿和氧化镁,模拟猪粪厌氧发酵过程中对H2S产生和释放的影响。在18 d的持续实验中,对发酵液中pH和发酵气体中H2S浓度变化进行全程监控,结果表明：添加赤铁矿对发酵体系的pH无明显影响,而添加氧化镁可显著提高发酵体系的pH值;添加2种矿物越多,气体中H2S含量越低。推测2种矿物对H2S产生的抑制在机制上有所不同。赤铁矿主要通过还原分解消耗H＋和沉淀消耗S2-的方式抑制H2S的产生;氧化镁则主要通过提高体系pH值,抑制SRB的活性以及降低H2S在气相中的分配。     

纳米比亚西北部朝斯组铁矿成因及有利区段选择

纳米比亚西北部Kunene（库内内）省新元古界铁矿层分布广泛。经普查,在EPL4432及EPL4533矿权区铁矿规模均构成大型矿床。铁矿床赋存于新元古界Damara(达马拉)层序的Chuos（朝斯）组上段与下段层位中（分别简称为“上矿层”和“下矿层”）。EPL4432下层矿中主要矿物为磁铁矿,EPL4533下层矿主要矿物为赤铁矿,同一层位出现不同的矿物类型,据分析这主要是赤铁矿受热液改造成磁铁矿造成的。经综合分析,纳米比亚西北部Chuos组铁矿的成矿类型为沉积-热液改造型,Chuos组下矿层分布地段为有利的成矿地段     

重庆桃花赤铁矿地质特征与成矿规律分析

桃花赤铁矿位于川东褶皱带与川湘凹陷的过渡带,矿区出露一套以砂岩、泥岩、灰岩为主的沉积层。上泥盆统黄家蹬组(D3h)为桃花赤铁矿的赋矿地层,矿体呈层状、似层状、透镜状分布于黄家蹬组上部,矿体与顶底板围岩界线清楚。黄家蹬组含Fe1和Fe2两层矿体,其中Fe1矿体无工业价值,Fe2矿体为矿区主矿体(层厚1.07m～5.89m)。矿区矿石为高磷、低杂质、较低品位酸性鲕状赤铁矿矿石,矿石因含泥质不同而呈紫红色或暗紫色,发育条带状构造和块状构造。依据矿床地质特征分析,桃花赤铁矿的分布主要受岩相古地理影响,矿体产出形态受褶皱构造控制。桃花赤铁矿属渝东鄂西"宁乡式"铁矿成矿区的西延部分,矿区泥盆系中统云台观组(D2y)和泥盆系上统黄家蹬(D3h)为一套海进过程中形成的滨海相沉积序列,矿体分布于细砂岩、粉砂岩、粉砂质页岩向页岩或碳酸盐岩过渡的层位。湿热气候和邻近海盆是形成赤铁矿矿的有利古环境,古海盆周围的古陆风化碎屑物是成矿的物质来源。矿区及其外围上泥盆统地层分布区是宁乡式赤铁矿的找矿远景区,褶皱是良好的构造找矿标志。     

An Experimental Study of Fe-Al Solubility in the System Corundum-Hematite up to 40 kbar and 1300{degrees}C

The mutual solubility in the system corundum–hematite[-(Al, Fe³⁺)₂O₃] was investigated experimentally using bothsynthetic and natural materials. Mixtures of -Al₂O₃ and -Fe₂O₃(weight ratios of 8:2 and 10:1) were used as starting materialsfor synthesis experiments in air at 800–1300°C withrun times of 7–34 days. Experiments at 8–40 kbarand 490–1100°C were performed in a piston-cylinderapparatus (run times of 0·8–7·4 days) usinga natural diasporite consisting of 60–70 vol. % diasporeand 20–30 vol. % Ti-hematite. During the diasporite–corunditetransformation, the FeTiO₃ component (12–18 mol %) ofTi-hematite only slightly increased, implying that oxygen fugacitywas maintained at high values. Run products were studied byelectron microprobe and X-ray diffraction (Rietveld) techniques.An essentially linear volume of mixing exists in the solid solutionwith a slight positive deviation at the hematite side. Up to1000°C, corundum contains <4 mol % Fe₂O₃ and hematite<10 mol % Al₂O₃; at 1200°C these amounts increase to9·3 and 17·0 mol %, respectively. At 1300°Chematite was no longer stable and coexists with the orthorhombic phase . The present results agree with corundum (solvus) compositions obtained inprevious studies but indicate a larger solubility of Al in hematite.The miscibility gap in the solution can be modelled with anasymmetric Margules equation with interaction parameters (2uncertainties): ; ; ; . Application of the corundum–hematite solution as a solvus geothermometer is limited because of thescarcity of suitable rock compositions. KEY WORDS: corundum; hematite; corundum–hematite miscibility gap; experimental study; Margules model; metabauxite     

The Hydrothermal Na—Ca Alteration at the Marginal Part of the Florina Granite and the Associated Magnetite—Hematite Bands With Thorium and Uranium Mineralization

The Oxia mineralized granite is the product of differentiation in the external parts of the Florina magmatic mass. Acidic hydrothermal solutions either of magmatic or of meteoric origin reacted with the upper tectonically fractured parts of the Florina granite and became enriched in iron, thorium, uranium, zircon and rare-earth elements. The most abundant alteration minerals are sericite and quartz, while the minerals of the mineralization bands include magnetite, hematite, thorite, monazite and zircon. The outer parts of the Oxia granite made it easy the percolation of hydrothermal solutions from the deeper heater to the upper cooler parts of the granite which acted as a hot spot.     

Anomalies of Thermomagnetic Characteristics of Lower Cretaceous Red-Beds in the Tadjik Depression (Southern Tien-Shan)

The paper features data on thermomagnetic characteristics of the red-bed sediments of the Lower Cretaceous of the Tadjik depression which turned out to be somewhat anomalous. The thermomagnetic characteristics of monolithic samples are stable under long-term heating (2–3 hours) at high temperature (600°–700°C). At the same time, the thermomagnetic characteristics of the powders, obtained from heated monolithic samples, display instability under even lesser temperatures. During heating at 600°–700°C, part of the hematite, dispersed in the rock, turns into stable maghemite. Disintegration of the monoliths changes the properties of the secondary maghemite - it becomes unstable to heating and at temperatures of 550°-600°C irreversibly changes into hematite.