铜陵凤凰山铜多金属矿磁铁矿单矿物稀土元素特征研究

通过对铜陵凤凰山铜多金属矿不同部位的磁铁矿单矿物的稀土元素配分分析,发现从矿体的底板经过中部到顶板,磁铁矿中稀土元素总量平均值不断升高,依次为11.30×10-6,29.34×10-6和86.15×10-6,δ(Eu)平均值依次为0.62,1.23和2.04.与超覆于矿体之上的花岗闪长岩体和矿体下伏的围岩(灰岩)的稀土...     

河南窑场和辽宁思山岭铁矿磁铁矿矿物学和氧同位素特征对比——对BIF型铁矿成因与形成环境的启示

河南窑场铁矿和辽宁思山岭分别位于华北陆块的南缘和东北缘。通过对其主要矿石矿物磁铁矿单矿物的化学成分、热电性及氧同位素的分析发现,磁铁矿均具高Ni低Co的特征,暗示成矿来源与深部物质有关。它们均相对富集轻稀土元素,显示Eu正异常和无明显Ce负异常,其中辽宁思山岭铁矿磁铁矿Eu异常较为强烈。此外,窑场和思山岭磁铁矿的δ¹⁸O、热电系数平均值分别为7.1‰、-59.05 μV/℃和2.3‰、-57.18 μV/℃。化学成分显示两者均应属火山沉积变质成因,其中思山岭磁铁矿类质同像程度较低,结构较为均匀。对华北陆块产出的主要铁建造岩群的磁铁矿δ¹⁸O值和稀土元素组成的对比分析结果显示,贫富矿石中磁铁矿氧同位素组成具有规律性,与富化机制有密切联系;不同岩群中贫矿石磁铁矿δ¹⁸O值高低与变质程度具有一定联系。根据中太古代-古元古代BIFs的Ce、Eu异常程度的综合分析结果,推测华北陆块BIFs形成时的古海洋整体上处于缺氧或少氧环境,但伴随华北陆块演化,还原环境影响趋弱,不利于条带状铁建造的形成。     

辽宁省下峪铁矿床地质特征及找矿标志

下峪铁矿床为沉积变质型铁矿。矿区岩浆活动较强,太古界鞍山群地层呈残留体形式分布在变质深成侵入体中,磁铁矿体赋存于鞍山群地层中,为斜长角闪岩中的夹层—磁铁石英岩。区内共圈出8条磁铁矿体,其中有7条出露地表。矿体普遍具绿泥石化、绢云母化、黄铁矿化及黄铜矿化。文章在详细研究矿床地质特征及地球物理特征的基础上,总结了该矿床的主要控矿因素及找矿标志,为进一步在该区找矿指明了方向。     

会东县菜园子磁铁矿床地质特征及成因

菜园子磁铁矿位于扬子地台西缘康滇地轴中段东缘,江舟—米市断陷盆地带南段,川滇黔相邻成矿区之会理—会东前寒武纪铁铜铅锌银成矿远景区内。通过对该矿床地质特征、物探异常特征与见矿效果的验证、矿体地质特征、围岩蚀变的分析,认为菜园子磁铁矿床为与晋宁期中基性次火山作用有关的"火山喷溢(发)—变质热液型"(赤)磁铁矿床。     

中国超贫磁铁矿资源的特征、利用现状及勘查开发建议——以河北和辽宁的超贫磁铁矿资源为例

近年来铁矿石价格的一涨再涨对中国的铁矿资源产生了重大影响：一方面,矿山的开采品位降低,一些原来不具经济意义的已查明的铁矿资源变得可以开采利用;另一方面,一些过去不认为是铁矿的含磁铁矿岩石成了可以开发利用的超贫磁铁矿资源。在调查研究的基础上,以河北和辽宁的超贫磁铁矿资源为例,对其类型、特征及开发利用现状进行了总结,并提出了勘查开发建议。     

Cosmic microspheres in the Carboniferous deposits of the Usolka section (Urals foredeep)

Magnetite microspheres from the Carboniferous deposits of the Usolka reference section were studied by probe microanalysis, with comparison of the distributions of chemical elements and microspheres. The presence of microspheres in sedimentary strata is considered to be an additional factor for stratigraphic correlation between sedimentary sections. The microspheres are shown to be of cosmic nature. The Late Paleozoic paleoclimatic changes (extreme cooling) and biotic crises were caused by the periodical Solar System motion in the Galaxy, cosmic-dust fallout, and meteorite bombardments of the Earth.     

Geochemical Characterization of Magnetite and Geological Setting of the Iron Oxide ± Iron Silicate ± Iron Carbonate Rich Pb–Zn Sulfides from the La Unión and Mazarrón Stratabound Deposits (SE Spain)

From a mineralogical point of view the La Unión ore field (SE Spain) can be regarded as an oddity as some of its hydrothermal, stratabound type deposits display an extremely unusual paragenesis comprising magnetite ± greenalite ± minnesotaite ± siderite and galena ± sphalerite (IOSC – LZS). Recent mineralogical studies have shown that this paragenesis is also present at the neighboring Mazarrón ore field. These ore fields share a similar geologic setting, involving metamorphic and sedimentary rocks (Paleozoic s.l. to Permian) hosting late Miocene high‐K calc‐alkaline volcanic and subvolcanic rocks. The latter have andesitic to dacitic composition, and triggered hydrothermal activity and ore deposition. This study discusses the detailed mineral chemistry of magnetite samples from Mazarrón and La Unión and provides some hints for the origin of the IOSC – LZS paragenesis. We performed electron microprobe (EPMA) analyses in magnetite samples from La Unión and Mazarrón to determine the contents of minor and trace elements (Zn, Ni, Mn, Cr, V, K, Ca, Ti, Al, Si, Mg). Given that some results fell below the detection limit for the EPMA instrumental conditions we used robust regression on order statistics (robust ROS), with the NADA package in R to deal with these data sets. The Ca + Al + Mn contents in magnetites from San Cristóbal and Emilia are equivalent to the mean contents of those of IOCG, Kiruna, BIF, Cu porphyry, skarn, VMS, hydrothermal and clastic Pb–Zn deposits, but they are low in Ti + V and Ni + Cr. The principal components analysis indicates that Zn, Ni, Cr, V, K, Ca, Ti, and Mg are roughly collinear, therefore correlated, being also independent from Fe. Besides, the function discriminant analysis of data shows that the magnetites from Emilia and San Cristóbal cluster in differentiated groups, thus probably reflecting some differences related to the distance to the magmatic source that triggered the hydrothermal system: proximal in the case of San Cristóbal and distal in Emilia.     

关于镜铁矿综合回收利用的试验研究

为了充分利用矿区内大量的镜铁矿资源,在原有工艺和试验研究的基础上,采用弱磁-强磁（两段）-摇床-分级工艺流程,在最终磨矿细度为-0.075 mm为95.10%的条件下,可得到产率29.46%、品位68.19%、回收率58.98%的综合铁精矿,及产率12.73%、品位68.89%、回收率25.75%的云母氧化铁产品,获得了良好的技术指标.     

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     

Chemistry of magnetite-apatite from albitite and carbonate-hosted Bhukia Gold Deposit,Rajasthan, western India – An IOCG-IOA analogue from Paleoproterozoic Aravalli Supergroup: Evidence from petrographic,LA-ICP-MS and EPMA studies

The Bhukia gold (+copper) deposit hosted by albitite and carbonates that occur within the Paleoproterozoic Aravalli-Delhi Fold Belt (ADFB) in western India consists of magnetite, graphite, apatite and tourmaline along with sulfide mineralization. Ubiquitous presence of magnetite and apatite in gold-sulfide association, alteration patterns and shear controlled mineralization suggest it to be IOCG (Iron-oxide copper gold) type deposits. The detailed mineral chemistry of magnetite and apatite are generated and interpreted in terms of their genetic significance, hydrothermal and magmatic origin vis-à-vis their affiliation with IOCG deposition. The data suggest that the magnetite has hydrothermal affiliation. The Ni/Cr ratio is greater than 1, which is explained by differences in solubility and mobility of Ni and Cr in hydrothermal fluids and is corroborated with other key evidences including that of wide ranging Mg concentration further supports a strong hydrothermal input that is envisaged for the deposition of magnetite. Concentration of vanadium in magnetite is generally <1000 ppm in case of barren hydrothermal occurrences while in the study area, it is relatively higher as it is attributed to the gold-sulfide-Cu mineralization. Ti vs Ni/Cr, Ni/(Cr+Mn) vs Ti+V, Ca+Al+Mn vs Ti+V and Al+Mn vs Ti+V variations are interpreted in terms of magnetite genesis. EPMA data suggests that apatite present in Bhukia is of fluorapatite variety with F content >1 wt% and F/Cl >1. Higher concentration of F and moderate Mn along with lower concentration of Cl attests their magmatic hydrothermal character and its derivation from meta-volcano sedimentary source. REE patterns obtained from LA-ICP-MS analysis suggest enrichment of LREE relative to MREE and HREE with negative Eu anomaly. Y/∑REE, La/Sm, Ce/Th and Eu/Eu¹ vs Ce/Ce¹ values of apatite is indicative of their origin in a highly oxidized environment. Presence of magnetite along with apatite is a common feature in IOCG-IOA (Iron-Oxide Apatite) association. Bhukia Gold Deposit has many similarities with Kiruna type Iron-Oxide Apatite (IOA) deposits particularly with respect to their similar tectonic setting, alteration patterns, mineral assemblages such as abundance of magnetite, apatite and presence of late stage sulfides based on EPMA and Laser ablation ICP-MS (LA-ICP-MS) studies. Lithological, petro-mineralogical and geochemical signatures of magnetite and apatite infer that the Bhukia is a possible IOCG-IOA type gold deposit typically associated with sulfides and graphite which may be used as petrogenetic indicators and pathfinders for exploration.