辽东硼矿床矿石的稀土元素特征及其地质意义

辽东硼矿床赋存于辽东古元古代的镁质火山-沉积地层中.矿石与含矿岩系具密切的交代继承关系：（1）矿石与含矿镁质岩石具交代继承的矿物组成、结构构造;（2）矿石的稀土元素特征主要受含矿岩系岩石的控制,在混合岩化弱的含矿岩系中,矿石的稀土元素特征与含矿镁质岩石相似,而在混合岩化强的含矿岩系中的矿石与混合岩的稀土元素特征相近;（3）辽东的硼矿床的形成是在混合岩作用过程中形成的含硼成矿流体交代镁质岩石的结果.     

辽东—吉南地区下元古界硼矿床成因的商榷——兼论容矿大理岩及硼矿矿床的成因

辽东—吉南地区下元古界产有丰富的硼矿资源,半个多世纪以来几乎所有硼矿地质勘查报告及有关论文、专著等无不涉及矿床成因。关于硼矿床成因主要有沉积变质成矿、沉积变质再造成矿、超变质热液成矿等3种观点(称传统观点,下同),传统观点认为硼的成矿物质来源于下元古界地层,经混合岩化或超变质热液将地层中分散的硼活化、迁移至镁质大理岩富集成矿。在编纂《中国矿产地质志·硼矿卷》过程中,对辽吉硼矿进行了新一轮研究,认为传统观点硼矿床成因值得商榷,并提出碳酸岩岩浆期后含硼热液交代早期喷溢的碳酸岩成矿的论说。     

辽东地区硼矿体赋存特征及成矿预测

辽东地区硼矿床受控于华北地台东北部大石桥-凤城-宽甸古隆起构造带.元古宇辽河群下部里尔峪组含硼岩系呈W-E、NE向、长约350 km、宽60 km的长条带状展布.硼矿体发育于里尔峪组蛇纹石化镁橄岩或蛇纹石化富镁大理岩中,具有明显的层控和岩控特征.虎皮峪-红石砬子-清河近东西向线状紧密的复式背、向斜间多期次次级的背、向斜发育,表现出明显的塑性变形.硼矿体在走向和倾向上具尖灭膨缩现象.围岩蚀变强烈.大量的电气石化使围岩中硼元素的含量偏高;蛇纹石化镁橄岩或蛇纹石化富镁大理岩的Ca/Mg比值波动极大,表明其与成矿关系十分密切;含硼岩系的厚度与矿体的关系呈正相关性,当厚度超过35 m时就有可能成矿,且厚度越大,矿体的规模和矿石质量越好.在部分地区,赋矿的褶皱构造完全倒转,有里尔峪组的层序倒转,混合岩段反转至上部,且混合岩化明显增强,形成混合岩化花岗岩,而其下部250~600 m是含硼岩系,发育优质隐伏硼矿.据辽东地区硼矿体的这些特征,推测了4个成矿远景区.     

辽东某硼矿山主要地质灾害特征及防治对策探讨

辽宁省某硼矿山已有35年的开采历史,现状地质灾害有巷道坍塌、采空区地面塌陷、矿坑突水,对矿山安全生产构成了一定的威胁．针对矿山的地质灾害特征提出了剥离堆积一定要先筑坝后堆放等8条防治对策。     

辽东—吉南地区硼矿床地质特征及成矿规律

辽东—吉南地区硼矿床产于早元古代辽东裂谷中,有硼镁石、含磁铁矿-硼镁石和磁铁矿-硼镁石3种矿床类型,分别赋存于下元古界宽甸群砖庙组下段、老营沟组中段和高小岭组下段,形成3个含硼原始沉积旋回,具严格的层控特点。裂谷阶段沉积的矿源层硼组分,溶于吕粱运动的区域变质和混合岩化的变质热液中,并在该时期的东西向褶皱层间剪切作用控制下,顺层侵位于褶皱翼部低压空间和轴部虚脱部位。成矿后构造对矿床具一定的改造作用,从而形成多成因多期次的沉积变质再造硼矿床。     

辽东硼矿的成矿机制及成矿模式

为了解辽东硼矿的成矿机制及建立成矿模式, 分析了含硼岩系、镁质容矿岩石、区域变质作用及混合岩化作用、构造等四大控矿因素, 发现含硼岩系具富硼特征, 容矿岩石具富镁特点并可成为硼质的沉淀剂, 含硼岩系中硼在区域变质和混合岩化过程中得到进一步活化形成含硼热液, 含硼热液在有利的构造空间交代镁质岩石即可形成镁硼酸盐型硼矿.含硼岩系、镁质容矿岩石是硼矿形成的物质基础, 区域变质及混合岩化作用、构造活动是硼矿形成的必要条件.辽东硼矿成矿模式为原始火山-沉积初始富集和部分熔融含硼热液交代镁质岩石.      

辽东南中生代构造演化及其与金矿形成的关系

辽东南地区中生代受到三期构造运动的影响且各具特色:①三叠纪的印支运动以形成东西向构造线及较多的"S"型花岗岩为特征;②侏罗纪的早燕山运动以近东西向挤压为主,在辽南地区以形成线理走向为北西西向的推覆构造为特征;③晚侏罗世晚期到早白垩世的晚燕山运动产生大量北东、北北东向断裂,同时发生了强烈的左行走滑。上述三期构造运动对金矿的形成均有一定的影响,三个时期均有一定规模的金矿化作用,金矿化的主要时期是在晚侏罗世晚期到早白垩世。     

辽东硼矿区层状混合岩的地质地球化学 特征及其成因探讨

辽东硼矿区层状混合岩为含硼岩系的一个重要组成部分,与各种变粒岩和浅粒岩呈整合接触而呈层状展布,在岩性上有过度现象。岩石中交代结构发育;与变质围岩相比,混合岩的SiO2、K2O、Na2O等组分均明显增加,而Fe2O3+FeO、CaO、MgO、MnO等组分明显减少,K2O/Na2O变化较复杂,岩石化学成分的变化与交代作用有关;微量元素具有与围岩相似的特征,稀土元素含量高于围岩,稀土元素配分模式与变粒岩一致,具有典型的重熔特征。这些特征表明层状混合岩是变质围岩经选择重熔交代而形成的。     

辽东-吉南硼矿的控矿因素及成矿作用研究

文章从区域成矿理论出发,分析了含硼岩系、镁质容矿岩石、区域变质及混合岩化热液交代作用、构造控制和改造等4大控矿因素在成矿过程中的作用。研究表明,含硼岩系、镁质容矿岩石是硼矿形成的物质基础,区域变质及混合岩化作用、构造改造活动是硼矿形成的必要条件;辽东-吉南硼矿的成矿作用为原始火山-沉积初始富集和部分熔融含硼热液交代镁质岩石的成矿作用过程。     

辽东－吉南地区早元古代硼镁石型硼矿床地质特征及矿床成因

通过对辽东－吉南硼矿床地质特征、矿床地球化学及Ｏ、Ｃ、Ｂ同位素特征的研究，结合数学地质方法分析认为辽东－吉南地区早元古代硼矿的成矿作用可分为沉积成岩成矿和变质－混合岩化改造成矿这两个主要成矿期。矿床成因类型为沉积变质改造型     

On the relationship between auriferous talc deposits hosted in volcanic rocks and massive sulphide deposits in Egypt

The volcanic-hosted massive sulphide (VHMS) deposits in the Eastern Desert of Egypt (e.g., Um Saki deposit) are associated with Precambrian coarse acid pyroclastic rocks. The upper contacts of the massive sulphide body are sharp and well-defined; while the keel zone to the mineralization is always associated with pervasive alteration, characterized by the presence of septechlorite and talc, associated with variable amounts of carbonate and tremolite. On the other hand, the economic talc deposits in Egypt are hosted intensively altered volcanic rocks. Besides talc, chlorite, carbonates and tremolite that occur in variable amounts in these deposits, anomalously high concentrations of gold are also present.The present study showed that alterations in the talc deposits of Darhib, El Atshan, Abu Gurdi, Egat, Um Selimat and Nikhira are similar to those occurring in the keel zone underlying the VHMS of Um Samuki and that the chemical modifications due to alteration processes (additions of Mg, Fe, Mn and Ca coupled with depletions in silica, alkalies, alumina and titanium) are comparable, even the host rocks are different, thus reflecting a genetic relationship. It is suggested that, the examined localities of talc deposits are hosted in the intensively altered volcanics in the keel zones of volcanogenic massive sulphide deposits. Recently, detailed geophysical prospecting program, including electric (resistivity, self-potential and induced polarization), electromagnetic and magnetic methods, was carried out at Darhib, Abu Gurdi and Um Selimat talc deposits. The quantitative interpretation of these geophysical measurements revealed the presence of subsurface bodies of sulphides. The present distribution of talc and allied minerals in Darhib, El Atshan, Abu Gurdi, Egat, Um Selimat and Nikhira could be explained by a tectonic process in which the coarse acid pyroclastic rocks with massive sulphides have tilted in such way that the footwall rock alterations (talc and allied minerals) are exposed on the present-day surface at these localities. Structural studies are currently under way in an attempt to explain the deformation regime that led to the present situation of talc deposits.Two distinct spatial and mineralogical associations of gold mineralization could be identified in the volcanogenic massive sulphide deposits and their footwall alterations (the keel zone) in the Eastern Desert of Egypt. These are (1) gold–silver–zinc association, and (2) gold–copper association. In the former, gold grades are very low and silver is anomalous. This association occurs typically in the upper levels of the VHMS deposit where low-temperature sulphides are abundant. Gold was deposited because of the mixing between the ascending hot solutions and the sulphate-rich seawater. The upper levels of Um Samuki sulphide body represent this association. Gold–copper association, on the other hand, typically occurs in the footwall altered rocks (the keel zone) and the lowest parts of the massive sulphide body. Gold grades reach up to 5.54 ppm, but the average is 1 ppm. Silver is very low, usually in the range of 4–10 ppm. Lead usually, but not always, accompanies gold in this association. Deposition of gold probably took place due to decreasing of temperature and/or increasing pH of the ascending hot brines. The keel zones at Darhib, Abu Gurdi, El Atshan, Um Selimat, Nikhira and Egat talc mines better represent this association.     

中国斑岩铜矿与埃达克(质)岩关系探讨

对比研究了中国26个主要斑岩铜矿的地球化学特征和年代学,结果表明其中25个矿床与埃达克(质)岩有成因联系,且多数与玄武质下地壳熔融形成的埃达克岩(C型)有关,现有数据表明土屋-延东和普朗斑岩铜矿可能与俯冲板片熔融形成的埃达克岩(O型)有关。容矿斑岩的初始锶值为0.7034～0.7090,均大于洋中脊玄武岩和亏损地幔的初始锶值,多数与EMI的初始锶值接近,推测其源区或源岩主要为玄武质下地壳,少数为洋中脊玄武岩,并受到中、上地壳不同程度的混染,这与两类埃达克岩的源区基本一致。虽然埃达克质岩浆具有形成斑岩铜矿的巨大潜力,但并非所有埃达克岩都能成矿,不同岩体需具体分析。     

Correlation between compositions of ore and host rocks in volcanogenic massive sulfide deposits of the Southern Urals

The geology and typification of volcanogenic massive sulfide (VMS) deposits of the Southern Urals are considered. The mineralogical-geochemical types of these deposits correlate with the composition of the underlying igneous rocks: Ni-Co-Cu deposits correlatedwith serpentinites (Ivanovka type); (Co)-Cu deposits, with basalts (Dombarovka type); Cu-Zn deposits, with basalt-rhyolite and basalt-andesite-rhyolite complexes (Ural type); and Au-Ba-Pb-Zn-Cu deposits, with basalt-andesite-rhyolite complexes with predominance of andesitic and felsic volcanics (Baimak type). The Ural-type deposits are subdivided into three subtypes: I, underlain by basalts (Zn-Cu deposits); II, hosted in felsic volcanic rocks of bimodal complexes (Cu-Zn deposits); and III, hosted in felsic volcanic rocks of continuously differentiated complexes (Zn-Cu deposits with Ba, Pb, and As). The above types and subtypes bearing local names are compared with global types of VMS deposits (MAR, Cyprus, Noranda, and Kuroko), to which they are close but not identical.     

蚀源区地质体铀浸出率与砂岩铀矿成矿关系

通过吐哈盆地南缘觉罗塔格山系和准噶尔盆地周缘（不包括准盆南缘北天山山脉）不同岩石浸出试验发现，同属中晚古生代的侵入岩、火山岩及变质岩，在相同条件下其铀浸出率有明显差异，即吐哈盆地南缘各类岩石的总浸出率在14.30%，而准噶尔盆地周缘（不包括准盆南缘北天山山脉）岩石的总浸出率仅为1.81%，这也许正是吐哈盆地南缘形成万吨级砂岩铀矿，而准盆北部（顶山地区）砂岩铀矿成矿前景欠佳，目前只有个别工业铀矿孔及部分矿化孔，而不具工业意义的原因之一。     

The geochemical features of terrigenous host rocks at massive sulfide deposits in the eastern Caucasus

Based on a great body of factual data, geochemical peculiarities in the distribution of rare, noble, radioactive, and other trace components in the Lower-Middle Jurassic terrigenous ore-enclosing (hereafter, host) rocks at massive sulfide deposits in the Vostochnyi (eastern) segment of the Greater Caucasus are high-lighted. Study of the Filizchai base metal massive sulfide deposit made it possible to define general regularities of element distribution in the ore body and altered wall rocks that reflect the general geochemical zonality. Concentrations of most components depend on the lithology and wall-rock alteration, distribution of rocks in the section, proximity of the contacting ore, and its mineral composition. Contents of typical elements in host rocks are closely associated with their concentrations in the ore bodies.     

Indium in cassiterite and ores of tin deposits

The results obtained with LA-ICP-MS by less abundant lighter ¹¹³In isotope and EPMA show that in cassiterite of cassiterite–quartz veins the indium contents do not exceed 160 ppm, while cassiterite from Sn–sulfide veins is characterized by higher indium contents from 40 to 485 ppm; sulfides of Sn–sulfide veins unlike sulfides of cassiterite–quartz veins also have the highest indium contents: Fe-sphalerite (100–25,000 ppm), chalcopyrite (up to 1000 ppm), and stannite (up to 60,000 ppm). Indium contents in the Sn–sulfide ore of the Tigrinoe and Pravourmiiskoe deposits obtained using SR-XRF, ICP-MS and atomic absorption methods range from 10 to 433 ppm with average values of 56–65 ppm. Indium-rich Sn–sulfide mineralization in five large Sn–Ag ore districts of the Far East Russia (Khingansky, Badzhalsky, Komsomolsky, Arminsky, Kavalerovsky) provides the impetus for further exploration of deposits with Sn–sulfide mineralization as the most promising indium resources in Russia. Empirical observations from geology and geochronology of cassiterite–quartz and Sn–sulfide mineralization show that the combined contribution from granite and alkaline–subalkaline mafic sources and multistage ore-forming processes doubled indium resources of deposits being the main factors in the formation of high grade indium mineralization.     

The sulfur isotopic composition of sulfides from ores and host rocks of the Upper Kolyma region,Magadan Oblast

More than 200 analyses of the sulfur isotopic composition of sulfides from various terrigenous and intrusive host rocks, metasomatically altered wall rocks, and gold lodes of the Upper Kolyma region are presented. In accessory pyrite of the metaterrigenous rocks, δ³⁴S varies from ?23.1 to +5.7‰ δ³⁴S of pyrite and arsenopyrite from gold-quartz mineralization is within the range ?10.6 to ?0.4‰ and is close to the average δ³⁴S of pyrite from the metaterrigenous rocks (?4.4‰). In the intrusive rocks, δ³⁴S of pyrite varies from ?3.8 to +2.6‰ (+0.7‰, on average) and drastically differs from δ³⁴S of arsenopyrite from postmagmatic gold-rare-metal mineralization (?7.9 to ?2.7‰; ?5.2‰, on average). The comparison of the δ³⁴S of accessory sulfides from the host rocks with δ³⁴S of sulfides from the gold deposits suggests that sulfur mobilized from the terrigenous sequences participated in the hydrothermal process. The results obtained are consistent with the metamorphic model of the formation of gold-quartz deposits in the Upper Kolyma region.     

东疆沙泉子铜和铜铁矿床岩（矿）石地球化学研究与地质找矿前景

沙泉子铜铁矿床安山岩类和闪长岩属偏碱性的钙碱性系列。（玄武）安山岩中含SiO2在49．2％．59．97％，多数样品含铝在16．66％以上，具有高铝玄武安山岩特点，含Na2O为2．19％～5．1％，K2O为0．61％．3．2％，（Na2O＋K2O）为5．32％-7．03％，Na2O／K2O值在1．07-8．36。本区安山岩类和闪长斑岩具有明显的Rb、Th-U-K、La-Ce、Pb和P正异常，富集大离子亲石元素（LILE）和轻稀土元素（LREE），具有明显的Ta．Nb、Sr负异常、中等Eu和Ti负异常，地球化学特征表明它们可能形成在活动大陆边缘上的陆缘岛弧构造背景中。这对于形成大型-超大型斑岩-夕卡岩型铜和铜铁矿床十分有利，深部隐伏矿床的找矿勘查是今后主攻方向。