扬子地台北缘锰矿成矿地质特征及找矿方向研究

扬子地台北缘与秦岭褶皱系的南缘,自东向西分布着3个三级构造单元.扬子地台北缘多个拉张盆地及陆内同生盆地,对锰矿的空间分布具有重要的控制作用,形成了巴山锰矿带、南秦岭锰矿带和摩天岭锰矿带.各锰矿带在锰矿成矿地质条件等方面既具有相同之处,又具有各自的特点.文章通过对各成矿带锰矿成矿地质特征和典型矿床调查与分析研究,对锰矿成矿规律提出了一些新的认识,并对该区今后锰矿找矿方向提出了初步认识.     

豫南灵山岩体铀矿化特征

地处豫南的灵山岩体,分布着丰富的矿产资源。笔者以灵山岩体铀矿化分布特征为切入点,阐述灵山岩体铀矿化特征。该岩体铀矿化受构造、裂隙的控制,有利成矿部位在岩体中构造带与脉岩相交复合部位,矿化富集地段多含铁质、锰质和泥质,且热液蚀变发育。铀源来自岩体。具有4种矿化类型。总结其矿化特征,对豫南新县岩体、商城岩体的找矿具有一定指导意义。     

Specific features and composition of the Akkermanov manganese deposit

New data on the Akkermanov deposit characterized by specific structure and composition of primary (carbonate) and secondary (manganese oxide) ores are presented. Distribution of mineralization in host rocks and weathering crusts is considered. It is shown that manganiferous carbonate rocks, which host orebodies, formed in a marine basin with well-aerated bottom waters. Oxide ores are mainly composed of crystalline pyrolusite produced by multiple processes of the oxidation of manganese compounds. In this respect, the Akkermanov deposit differs drastically from all manganese deposits developed in Russia and Ukraine.     

Stable isotope evidence for the origin of diagenetic carbonate minerals from the Lower Jurassic Inmar Formation, southern Israel

The oxygen isotope compositions of diagenetic carbonate minerals from the Lower Jurassic Inmar Formation, southern Israel, have been used to identify porewater types during diagenesis. Changes in porewater composition can be related to major geological events within southern Israel. In particular, saline brines played an important role in late (Pliocene-Pleistocene) dolomitization of these rocks. Diagenetic carbonates included early siderite (δ¹⁸O_SMOW=+24.4 to +26.5‰δ¹³C_PDB=?1.1 to +0.8‰), late dolomite, ferroan dolomite and ankerite (δ¹⁸O_SMOW=+18.4 to +25.8‰; δ¹³C_PDB=?2.1 to +0.2‰), and calcite (δ¹⁸O_SMOW=+21.3 to +32.6‰; δ¹³C_PDB=?4.2 to + 3.2‰). The petrographic and isotopic results suggest that siderite formed early in the diagenetic history at shallow depths. The dolomitic phases formed at greater depths late in diagenesis. Crystallization of secondary calcite spans early to late diagenesis, consistent with its large range in isotopic values. A strong negative correlation exists between burial depth (temperature) and the oxygen isotopic compositions of the dolomitic cements. In addition, the δ¹⁸O values of the dolomitic phases in the northern Negev and Judea Mountains are in isotopic equilibrium with present formation waters. This behaviour suggests that formation of secondary dolomite post-dates the tectonic activity responsible for the present relief of southern Israel (Upper Miocene to Pliocene) and that the dolomite crystallized from present formation waters. Such is not the case in the Central Negev. In that locality, present formation waters have much lower salinities and δ¹⁸O values, indicating invasion of freshwater, and are out of isotopic equilibrium with secondary dolomite. Recharge of the Inmar Formation by meteoric water in the Central Negev occurred in the Pleistocene, and halted formation of dolomite.     

湖南省沉积型锰矿地质环境及成矿作用

湖南省沉积型锰成矿时代跨度大,最早由早元古代板溪群马底驿期至早二叠世孤峰期。其中,早南华纪大塘坡期、中奥陶世烟溪期及中二叠世孤峰期为三个最主要成锰集中期,并且大体呈现出朝东南方向成矿时代变新的趋势。成锰沉积盆地是锰矿床就位的重要场所,相应的岩相古地理环境为锰成矿创造了有利条件,即相对缺氧的、滞流的安静环境。这种环境在诸多古地理环境中都可以形成,导致了锰成矿岩相古地理环境的多样性,如浅海陆棚相、次深海棚缘盆地相、次深海台缘斜坡相及陆表次深海海盆相。三个主要成锰期锰成矿作用具有统一性,成矿作用与地壳拉张、海侵事件、缺氧事件等区域性重大地质事件关联密切。     

基于OLI和GF-2数据的锰矿化信息提取分析与对比 —以新疆西昆仑玛尔坎苏锰矿带为例

本文在充分分析锰矿样品的实测波谱典型特征和矿化蚀变信息提取方法的基础上,基于Landsat OLI数据和国产GF-2数据影像,利用主成分分析法（PCA）对新疆西昆仑玛尔坎苏锰矿带进行了锰矿化异常信息提取,并对这两类数据的锰矿化信息提取结果进行了对比分析,进而讨论两类数据在锰矿化信息提取精度上的差异。研究表明：基于OLI和GF-2两类多光谱数据提取的锰矿化信息都取得了良好的效果,将已有的锰矿区与锰矿化点全部提取了出来,同时也提取出了未开采的锰矿化异常信息,验证了所采用信息提取方法的有效性;相比空间分辨率较低的OLI数据,高空间分辨率的国产GF-2遥感数据能够更好地区分锰矿化异常与阴影,更能精确地识别锰矿化异常的分布。因此,高空间分辨率多光谱数据在区分光谱特征差异较小的地物时具有较大优势,可为研究区下一步遥感找矿预测提供有利线索。     

从地洼成矿作用看中国某些优质锰矿的成因与远景

研究发现中国某些优质锰矿,属复成矿床,它们都是地洼成矿作用的产物。福建连城锰矿就是典型实例,类似矿床特别是复成风化锰矿,还见于闽西南-粤东北及湖南。滇东南一些锰矿,例如著名的斗南锰矿与白显锰矿的成因,也可能与地洼成矿作用有一定联系。分析对比了一些优质复成锰矿和一些较贫的复成锰矿的成矿地质条件。从地洼成矿作用可以看出中国某些优质锰矿的成因与远景。提出在中国东南地洼区、南北地洼区南端及云贵地洼区某些地方,寻找优质复成风化锰矿与复成菱锰矿—硫锰矿矿床是较有希望的。     

Copper mineralization in sedimentary cover associated with tectonic elements and volcanism in Israel

Copper mineralization occurs within the thick Cretaceous to Neogene sedimentary cover of central and northern Israel. Two distinct types of copper-rich anomalies are encountered. One form of copper mineralization is characterized by the presence of copper minerals such as malachite, atacamite, paratacamite, chrysocolla, and/or chalcopyrite forming veins and concretions within the sedimentary host rocks. The second type of copper enrichment is found dispersed within iron oxide veins associated with enrichments of other trace metals such as Ni, V, Zn, Co, Mo, and As. Both forms of copper anomalies lie along and are confined to the vicinity of tectonic elements. These features may be the surface expression of the longitudinal faults of the Dead Sea Rift Valley, of the transverse shear zone of southern and central Negev, or of the EW-trending horsts and grabens of central Israel. In many cases the copper anomalies are found near to or at the contact of volcanic bodies of intermediate to basic composition; in others, they are found in the vicinity of thermal springs. The fault zones may have provided conduits along which solutions, in places possibly briny, could have risen and leached subsurface mineralized volcanic or sedimentary bodies.     

再论锰的“内源外生”成矿说

锰矿地质研究一直受到中外地质学界的重视。锰质来源研究,事关锰矿勘查活动的部署依据和找矿预测的成败。1996年,我们率先提出锰的“内源外生”成矿说。一直到20世纪末,中外锰矿地质学界的主流学说认为,形成锰矿床的锰质主要来自于大陆风化。最近,业界有学者新建锰矿“内生外成”模式,这一模式尚需经历科学与实践的检验。     

Oxidation and Mineralization of Mn2+ Ions Mediated by Pseudomonas putida: Insights from an Experimental Study

The formation of manganese oxides in nature is commonly mediated by microorganisms.In this study,the mineralization of biogenic manganese oxidation mediated by Pseudomanas putida has been experimentally investigated by employing various characterization techniques,including SEM,FESEM,TEM,XRD,and STXM-NEXAFS.The results indicate that Mn~(2+) ions can be oxidized into Mn(Ⅳ) minerals(birnessite and pyrolusite) and Mn(Ⅲ) minerals(hausmannite and feitknechtite),successively.The primary products(birnessite and pyrolusite) further transformed into hausmannite and feitknechtite under Mn~(2+) ion-enriched conditions.However,birnessite and pyrolusite are the endproducts of the continuous microbial oxidation processes.These biogenic Mn oxides are poorly crystallized,which provides them with a high potential for usage in environmental restoration of contaminated soils and waters contaminated with heavy metals.The approaches employed in this study will also enrich genesis research of biological oxidation of Mn(Ⅱ) species in nature.     

Sources and formation conditions of ferromanganese mineralization of the Bureya and Khanka massifs,Russian Far East

The geochemical features of typical representatives of ferromanganese deposits are studied in the eastern Bureya and Khanka massifs (Russian Far East). Based on the major-, trace-, and rare-earth element distribution, the hydrothermal–sedimentary (with hydrogenic component) nature of their mineralization is established and the geodynamic setting and depth of ore formation are estimated. The differences in the depth and redox conditions of ore formation resulted in the metallogenic zonation of the Khingan block (Bureya Massif), which is expressed in a westward change in ore composition from the magnetite ores of the Kosten’ga–Kimkan zone to the hematite–magnetite and iron–manganese ores of the South Khingan zone. The conclusions about the participation of hydrothermal sources in the formation of ore mineralization of the studied deposits and the specifics of their localization require revision of the strategy of exploration and evaluation of ferromanganese ores in the southern Far East.     

Characteristics of Gold Mineralization at the Ciurug Vein, Pongkor Gold-Silver Deposit, West Java, Indonesia

Abstract. The Pongkor Gold‐Silver Mine, Bogor district, West Java, is approximately 80 km southwest of Jakarta. The gold and silver mineralization in the area is present in a deposit consisting of an epithermal vein‐system named individually as the Pasir Jawa, Gudang Handak, Ciguha, Pamoyanan, Kubang Cicau, and Ciurug veins. In the area studied, rocks of basaltic‐andesitic composition are dominated by volcanic breccia and lapilli tuff, with andesite lava and siltstone present locally. The hydrothermal alteration minerals in the Ciurug area are typical of those formed from acid to near‐neutral pH thermal waters, where the acid alteration is distributed from the surface to shallow depth, while the near‐neutral pH alteration becomes dominant at depths. The Ciurug vein shows four main mineralization stages where each discrete stage is characterized by a specific facies; these are, from early to late: carbonate‐quartz, manganese carbonate‐quartz, banded‐massive quartz and gray sulfide‐quartz facies. The major metallic minerals are pyrite, sphalerite, chalcopyrite and galena; they occur in almost each mineralization stage. Bornite was observed only in the southern part of the Ciurug vein at a depth of 515 m, and the occurrence of this mineral is reported here for the first time. Electrum and silver sulfides (mostly acanthite) are minor, whereas silver sulfosalts, stromeyerite and mckinstryite, and covellite are in trace amounts. The silver sulfosalts have compositional ranges of pearceite, antimon‐pearceite and polybasite. Most of the electrum occurs coexisting with other sulfide minerals, as inclusions in pyrite grains, with very little as inclusions in chalcopyrite or sphalerite. Gold grades within the Ciurug vein vary from 1.2 to hundreds of ppm, where the highest gold grade occurs in the latest mineralization stage in a thin sulfide band in vein quartz. Fluid inclusion microthermometry of calcite and quartz indicates deposition throughout the mineralized veins in the range from 170 to 230d?C and from low salinity fluids (predominantly lower than 0.2 wt% NaCl equiv.). Fluid inclusions occur with features of boiling.     

中钢澳大利亚 Carpentaria 锰矿矿权区 ASTEＲ数据蚀变信息提取研究

应用 ASTEＲ 多光谱卫星遥感数据,根据与锰矿相关的蚀变矿物光谱特征,采用主成份分析算法,提取了中钢集团所属的澳大利亚 Carpentaria 锰矿矿权区铁染、羟基、碳酸盐化、锰和硅化的蚀变信息。ASTEＲ 数据在锰矿化蚀变信息提取中能更好的识别不同类型含羟基蚀变矿物,能更好的提取含三价 Fe 离子的蚀变信息及锰矿物蚀变信息。对这些蚀变信息进行深入分析将有助于矿权区锰矿地质研究和勘查目标的确定。     

Plio–Pleistocene Hydrothermal Activity Related to Gold Mineralization in the Seta Area, Northeastern Hokkaido, Japan

Abstract: Plio–Pleistocene hydrothermal activity resulted in high grade low sulfidation epithermal gold mineralization in the Seta area, the southern end of the Monbetsu-Kamishihoro Graben of northeastern Hokkaido, Japan. Hydrothermal activity and accompanying hydrothermal eruptions began at approximately 2 Ma along NNW-SSE trending faults, the Tohbu-ko fault I and II. This activity resulted in two main zones of gold mineralization, the west quartz-adularia veins(QAV) and east stock-work zone(STZ), formed between 1. 8 and 1. 2 Ma. A smectite-chlorite alteration zone is observed at deeper levels, while kaolinite and kaolinite-smectite zones occur at shallower levels with an acid-leached zone present near the surface. The kaoli-nite and kaolinite-smectite zones are also distributed along faults and the STZ, to depths of several hundred meters. δ³⁴S values of pyrite and alunite from the kaolinite and silicified zones indicate alunite formed by the oxidation of sulfide, either H₂S(vapor) or mineral.
Formation of the STZ and the southern part of the QAV took place during lacustrine sedimentation, while formation of the northern part of the QAV took place after eruption of andesitic lava; the latter being associated with widespread alteration formed under neutral-pH conditions. δ¹⁸O values of quartz veins and silicified rocks indicate that the paleo-hydrothermal waters have a large meteoric component, increasing with decreasing depth in the STZ. Acid hydrothermal waters, resulting from near surface oxidation of H₂S were responsible for acid-leaching and kaolinization of surrounding rocks. Between 1. 4 and 0. 3 Ma, the acid hot waters drained back along the STZ to depths of at least 500m, as a result of a fall in the paleo-water table level.     

由层序地层学角度分析大塘坡式锰矿沉积过程——以湘西北民乐锰矿为例

以湘西北民乐锰矿为例,基于矿区内钻孔信息对成矿期（大塘坡组下段）进行地层对比,由新分层信息及厚度变化分析沉积特征并建立三级、四级层序格架,由三级、四级层序尺度的古地貌变化分析成矿期沉积演变特征。主要认识有:1）民乐锰矿含矿层（大塘坡组下段）可根据岩性细分为下亚段1段（致密块状、密集条带状矿体夹黑色炭质页岩）、下亚段2段（黑色页岩夹薄层锰矿条带）、上亚段（黑色炭质页岩夹黄铁矿）。2）民乐锰矿的三级层序凝缩层体系域可划分为四个四级层序,其中第二、三层序菱锰矿发育较厚,形态以块状和密集条带状为主;第一、四层序菱锰矿发育薄,形态多为条带状。3）民乐锰矿沉积过程可以通过三级层序和四级层序两个研究尺度共同解释,三级层序尺度解释锰矿沉积过程,而四级层序尺度则揭示了多期不同形态、厚度锰矿的沉积过程。     

Genesis for Rare Earth Elements Enrichment in the Permian Manganese Deposits in Zunyi,Guizhou Province,SW China

The Zunyi manganese deposits, which formed during the Middle to Late Permian period and are located in northern Guizhou and adjacent areas, are the core area of a series of large-medium scale manganese enrichment minerogenesis in the southern margin and interior of the Yangtze platform, Southern China. This study reports the universal enrichment of rare earth elements(REEs) in Zunyi manganese deposits and examines the enrichment characteristics, metallogenic environment and genesis of REEs. The manganese ore bodies present stratiform or stratoid in shape, hosted in the silicon–mud–limestones of the Late Permian Maokou Formation. The manganese ores generally present lamellar, massive, banded and brecciated structures, and mainly consist of rhodochrosite, ropperite, tetalite, capillitite, as well as contains paragenetic gangue minerals including pyrite, chalcopyrite, rutile, barite, tuffaceous clay rock, etc. The manganese ores have higher ΣREE contents range from 158 to 1138.9 ppm(average 509.54 ppm). In addition, the ΣREE contents of tuffaceous clay rock in ore beds vary from 1032.2 to 1824.5 ppm(average 1396.42 ppm). The REEs from manganese deposits are characterized by La, Ce, Nd and Y enriched, and existing in the form of independent minerals(e.g., monazite and xenotime), indicating Zunyi manganese deposits enriched in light rare earth elements(LREE). The Ce_(anom) ratios(average-0.13) and lithofacies and paleogeography characteristics indicate that Zunyi manganese deposits were formed in a weak oxidation-reduction environment. The(La/Yb)_(ch), Y/Ho,(La/Nd)_N,(Dy/Yb)_N, Ce/Ce* and Eu/Eu* values of samples from the Zunyi manganese deposits are 5.53–56.92, 18–39, 1.42–3.15, 0.55–2.20, 0.21–1.76 and 0.48–0.86, respectively, indicating a hydrothermal origin for the manganese mineralization and REEs enrichment. The δ~(13) C_(V-PDB)(-0.54 to-18.1‰) and δ~(18) O_(SMOW)(21.6 to 26.0‰) characteristics of manganese ores reveal a mixed source of magmatic and organic matter. Moreover, the manganese ore, tuffaceous clay rock and Emeishan basalt have extremely similar REE fractionation characteristic, suggesting REEs enrichment and manganese mineralization have been mainly origin from hydrothermal fluids.     

Manganese mineralization in Archean greenstone belt,Joda–Noamundi sector,Noamundi basin,East Indian Shield

A Mesoarchean greenstone belt (3.5–3.0 Ga) in the western part of the East Indian Shield comprising the Iron Ore Group of the Noamundi basin contains economic resources of both iron and manganese ores in the NNE plunging regional synclinorium. Manganese mineralization in the central and eastern parts of this synclinorium, particularly in Joda–Noamundi sector, has taken place in multiple cycles starting from syngenetic sedimentary and exhalative type through mobilization and remobilization in different stages of tectonism, deformation and hydrothermal activities to latest lateritic or supergene type. A relatively high temperature metamorphic jacobsite–hausmannite–bixbyite–braunite assemblage, low temperature hydrothermal pyrolusite–psilomelane–hollandite assemblage and supergene pyrolusite–manganomelane–groutite–polianite assemblage are present and were formed by recycling of manganese in different stages of mineralization. A detailed structural study of the manganese ore bodies as well as their ore petrographic and mineralogical characteristics with mineral chemistry has revealed systematic mineralization and their relation to deformational phases. Such recycling of manganese and its structural control of mineralization in different phases is unique of its kind in comparison with other Archean manganese deposits in the world.     

湘西北地区民乐式锰矿成矿地质特征及矿床成因

在野外考察和室内综合研究基础上,从地层岩性、岩相古地理、地质构造等成矿地质条件的分析入手,结合稳定同位素测试数据分析,以古丈锰矿田中的野竹锰矿为例,对湘西北民乐式锰矿床的成矿地质特征及成矿机制进行了探讨,认为区内成矿物质（锰）是多来源的,但主要来源于海底火山活动。在成矿作用过程中,堆集在火山喷口附近的沉积物被烘热的海水淋滤改造,从中析出锰质,由热海水体所挟带,随海流迁移,成矿物质在裂陷槽中沉积下来富集形成锰矿床。民乐式锰矿床属离火山喷发中心较远的海底火山喷发-沉积锰矿床。     

湘西北民乐锰矿成矿后变化分析

大塘坡式锰矿成矿后变化程度可从地层抬升程度、氧化程度、构造条件、裂隙与岩溶发育程度、顶底板隔水性、地表及气候等方面进行分析评价。民乐锰矿成矿后受到近地表因素、地下水的以及断层发育的影响,其成矿后变化程度可从地层抬升程度、断裂发育程度以及含锰岩系隔水性三方面进行评价。选取含矿层埋深、距断层距离、矿体上覆及下伏黑色页岩段厚度对三个评价因素进行定量表征,制作单因素等值线图并量化评分,运用层次分析法确定各因素权重,将各单因素加权叠加绘制成矿后变化程度系数等值线图,将成矿后变化程度分区与锰矿形态（品位）、厚度范围叠加,定量分析成矿后变化对找矿的指示意义。研究发现,断裂发育程度对于民乐矿区成矿后变化程度最为重要,地层抬升程度次之,含锰岩系隔水性影响较少;民乐矿区成矿后变化程度具有“两侧高、中心低”的特征,呈现从盆地中心至边缘带递增的趋势,西侧更多受地层抬升影响,东侧则以断裂影响为主;成矿后变化程度较低的区域更有利于找矿,但对于不同形态（品位）的矿体指示性并不明显;对各类地质演化过程的恢复和定量表征应成为今后大塘坡式锰矿成矿后保存改造研究的主要方向。     

Gibbsite mineralization and its genetic implication for the Um Bogma manganese deposit,southwestern Sinai

Gibbsite mineralization is found in the Um Bogma region, southwestern Sinai, predominantly in the Um Bogma Formation, and to a lesser extent also in the Abu Thora Formation, at the base of a carboniferous sequence. This region is well known for the manganese ore lenses which occur in the dolomite beds at the base of the Um Bogma Formation. The gibbsite generally occurs in discordant veins and pockets within the dolomite. Most of the gibbsite bodies are associated with N-NW Tertiary faults or joints, and with dyke contacts and planes of weakness. The common associated minerals are clays, predominantly kaolinite, gypsum, halite, manganese and iron oxides. In the gibbsite, Pb, Zn and Cu are anomalously high, as is the fluoride content identified in the clay fraction. From stratigraphic, tectonic, petrographic and geochemical evidence it is concluded that the gibbsite mineralization took place during the Tertiary and is of hypogene origin. This hypogene activity also caused intensive leaching and alteration of the Um Bogma dolomites and remobilization of Mn + Fe ore bodies. This interpretation is reinforced by the geochemical similarities of the hot springs and trapped formation waters in the Nubian Sandstones along the Gulf of Suez.