内蒙古白云鄂博北部金矿成矿特征及找矿方向

白云鄂博位于华北地台与内蒙地槽接合部,其北部位于华北地台北缘狼山—白云鄂博台缘白云鄂博褶断束,已发现有赛乌素和干斯陶勒盖2个浅成中低温热液型金矿床,主成矿期的成矿温度为200～280℃,成矿压力为3 0×108～5 0×108Pa。微量元素、稀土元素和H、O同位素特征表明,白云鄂博群浅变质岩为矿源岩。区内轴向近EW,轴面N倾,向W侧伏的同斜背斜是控矿构造,由其派生的纵张断裂是主要的容矿构造。近年来,构造蚀变破碎带型、糜棱岩型等新类型金矿体及其深部盲矿体的发现,揭示了该区具有较大的找矿潜力。依据成矿控制条件,结合物化探测量成果,圈定了干斯陶勒盖—敖勒呼地区和赛乌素 号脉群西部及深部2处找矿靶区。     

内蒙古赛乌素金矿床成矿地质特征及找矿预测

赛乌素金矿床位于华北板决北缘、狼山-白云鄂博裂谷带白云鄂博群浅变质岩系内.矿床成因属浅成中低温热液型金矿床,矿石类型以石英脉型为主,尖灭再现、膨大收缩、雁列侧伏特征明显.区内哈拉忽鸡复背斜及EW、NW向断裂为主要控矿构造,具多期性、叠加性特点.根据区域金成矿规律、控矿地质条件、探采对比以及隐伏矿体的发现,证实南北矿带具备中深部和边部找矿潜力.     

内蒙古中部地区中新元古代黑色岩系中的金矿床及找矿远景

内蒙古中部地区中-新元古代黑色岩系发育,形成于渣尔泰白云鄂博裂陷槽内,命名为渣尔泰群和白云鄂博群。目前,仅在白云鄂博群的黑色岩系中发现并勘查了一批原生金矿。矿石主要类型为细脉型和蚀变变质岩型。金矿受层位和构造破碎带控制,金平均品位低,可形成大型或超大型矿床。因此,内蒙古中部中-新元古代黑色岩系中金矿资源潜力大,找矿远景好。     

内蒙古赛乌素金矿床地质地球化学特征

赛乌素金矿床位于华北地台北缘狼山一白云鄂博台缘白云鄂博褶断束,矿石类型主要为含金石英脉型,流体包裹体研究表明,包裹体主要以V-L两相气液包裹体为主,及少量CO2包裹体;均一温度为131℃～311℃,平均213%.流体盐度为0.35%～6.74%(wt%NaCI).矿石黄铁矿、方铅矿的δ34S值为+4.69%o～+11.54%O;石英包体δ18OH2o值为3.6%o～4.1%o,δD值为-114%o～-119%o.反映了成矿流体为中-低温、低盐度热液,其来源可能为变质水和岩浆水的混合流体.矿石与地层微量元素对比及稀土元素地球化学特征反映成矿物质主要来自白云鄂博群尖山组地层.综合分析认为,赛乌素金矿床应为中-低温混合热液石英脉型矿床.     

白云鄂博地区构造格局与古板块构造演化

通过对白云鄂博及周边地区地质和构造形迹的系统调研,综合分析了白云鄂博地区的古板块构造单元、白云鄂博群的沉积构造背景以及白云鄂博地区的构造组合特征。白云鄂博群可以划分为三个沉积组合,它们分别代表中元古代、晚元古代和早古生代白云鄂博地区由陆内裂谷向陆缘裂谷转化到活动大陆边缘裂谷的沉积过程。白云鄂博地区以白银角拉克－宽沟断裂为界,南北两侧存在重大地质差异。断裂南侧的该群岩石不整合覆盖在相当于五台群的巴尔腾山群之上,是在华北陆壳基底上发展起来的陆缘沉积。局部碳酸盐岩和页岩层位在加里东期遭受了强烈的地幔流体改造,形成大规模稀土矿化;在海西期又遭受了强烈的区域变质改造。断裂北侧的白云鄂博群以发育蛇绿混杂岩－叠瓦状况断层－紧闭同斜褶皱为特征,具有古板块俯冲形成的加积杂岩特征。在此基础上,对白云鄂博地区的古板块构造演化动力学过程进行了初步总结。     

白云鄂博金矿、乌拉山金矿的发现及启迪

白云鄂博金矿、乌拉山金矿,是内蒙古近年来发现的两个中—大型金矿床。 白云鄂博金矿,地处白云鄂博铁矿东北5公里,位于白云鄂博铁矿北矿范围内,地质构造则为白云鄂博台缘坳陷带。川井—白云鄂博深大断裂在矿区通过。区内褶皱、断裂构造发育。在强烈构造活动过程中,伴随区域变质和岩浆活动,具有铁、铌、稀土、金的良好成矿条件。     

白云鄂博矿床成矿构造环境分析

白云鄂博矿床是世界著名的超大型铁铌稀土矿床,但因为其成因和形成时代的证据复杂多样,其成因、形成时代及其形成的大地构造环境均有多种不同认识。笔者等曾对赋矿白云岩成因、成矿时代及赋矿地层白云鄂博群的年代这两个关键问题进行了系统的地质、地球化学研究,获得了一系列关键证据,并对前人资料进行了系统地梳理,论证了白云鄂博矿床赋矿白云岩为一大型微晶丘,而微晶丘是热水沉积形成;确定其成矿时代及白云鄂博群的年代均为早古生代。本文进一步报道了在与白云鄂博群下部相当的腮林忽洞群中发现了宏体化石海绵和腹足类,在白云鄂博群中发现了与腮林忽洞群中相同的振动液化脉和振动液化角砾岩。从而笔者等认为,白云鄂博矿床成矿和白云鄂博群的沉积环境是早古生代被动大陆边缘。     

白云鄂博矿区深边部铁矿床勘查突破及启示

围绕白云鄂博矿山寻找铁矿接替资源的急迫需求,聚焦构造对深部矿体控制作用,开展复杂地形及强干扰地区重力-磁法-电法-高精度反射地震综合勘查示范研究.通过一系列专题地质填图和综合研究,笔者构建了白云鄂博矿床成矿模式和新的勘查模型,提出矿区近东西向逆-平移断层(F2)导致了主矿、东矿深部矿体向东平移的新认识,明确指出深部存在...     

内蒙古赛乌素金矿稳定同位素组成特征及成因意义

内蒙古赛乌素金矿位于内蒙古中部,是一个产于中-新元古代白云鄂博群变质碎屑岩中的中型石英脉型金矿.本文通过对氢、氧、硫、铅稳定同位素地球化学特征研究后认为,成矿热液主要来自岩浆水(图1),硫同位素具有花岗岩的特征,铅同位素特征表明铅来自地幔(图2),因此推断成矿物质主要来自于岩浆活动.     

内蒙古白云鄂博超大型稀土-铌-铁矿床控矿构造特征及深部找矿方向

对白云鄂博超大型稀土-铌-铁矿田内褶皱及断层构造特征进行了剖析和总结,认为矿区内构造活动演化具有多期性,中元古代—海西期至少发育4期构造活动,包括近东西向控岩断层(F1)、近东西向逆-平移断层(F2)、近东西向褶皱和韧性剪切构造、北东向左行走滑正断层(F3),并将其对成岩成矿的影响及控制作用作了详细分析。认为:①沿白云石碳酸岩与顶底板围岩界线分布的近东西向断层控制了白云石碳酸岩的产出和矿体的形成;②白云石碳酸岩侵位之后,近东西向逆-平移断层对矿体进行了第一次破坏,导致主矿、东矿的深部矿体向东平移,钻孔WK14-01的深部矿体应为主矿深部的矿体平移所致;③成矿期后发育一期近南北向的挤压变形事件对矿体进行了第二次破坏,导致矿区白云鄂博群紧闭褶皱的形成和矿体发生透镜体化;④主矿、东矿之间的北东向左行走滑正断层对矿体进行了第三次破坏,导致主、东矿位置的错动。这些认识将对矿区深部及外围找矿工作具有重要的指导意义。     

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.     

Définition d'une limite multicritère ; stratigraphie du passage Campanien–Maastrichtien du site géologique de Tercis (Landes,SW France)Definition of a multi-criteria boundary; stratigraphy of the Campanian–Maastrichtian interval of the geological site at Tercis (Landes,SW France)

Lithostratigraphy, physicochemical stratigraphy, biostratigraphy, and geochronology of the 77–70 Ma old series bracketing the Campanian–Maastrichtian boundary have been investigated by 70 experts. For the first time, direct relationships between macro- and microfossils have been established, as well as direct and indirect relationships between chemo-physical and biostratigraphical tools. A combination of criteria for selecting the boundary level, duration estimates, uncertainties on durations and on the location of biohorizons have been considered; new chronostratigraphic units are proposed. The geological site at Tercis is accepted by the Commission on Stratigraphy as the international reference for the stratigraphy of the studied interval. To cite this article: G.S. Odin, C. R. Geoscience 334 (2002) 409–414.     

The effect of water on accessory phase solubility in subaluminous and peralkaline granitic melts

The solubilities of columbite, tantalite, wolframite, rutile, zircon and hafnon were determined as a function of the water contents in peralkaline and subaluminous granite melts. All experiments were conducted at 1035 °C and 2 kbar and the water contents of the melts ranged from nominally dry to approximately 6 wt.% H₂O. Accessory phase solubilities are not affected by the water content of the peralkaline melt. By contrast, solubilities are affected by the water content of the subaluminous melt, where the solubilities of all the accessory phases examined increase with the water content of the melt, up to 2 wt.% H₂O. At higher water contents, solubilities are nearly constant. It can be concluded that water is not an important control of accessory phase solubility, although the water content will affect diffusivities of components in the melt, thus whether or not accessory phases will be present as restite material. The solubility behaviour in the subaluminous and peralkaline melts supports previous spectroscopic studies, which have observed differences in the coordination of high field strength elements in dry vs. wet subaluminous granitic glasses, but not for peralkaline granitic glasses. Lastly, the fact that wolframite solubility increases with increasing water content in the subaluminous melt suggests that tungsten dissolved as a hexavalent species.     

Late Wuchiapingian (Late Dzhulfian,early Late Permian) limestone olistolites within the Tertiary flysch of Glypia Unit (Mount Parnon,central–eastern Peloponnesus,Greece)

Some olistolites reworked in a Tertiary flysch of Mount Parnon (Peloponnesus, Greece) exhibit a Late Permian assemblage, dominated by Paradunbarula (Shindella) shindensis, Hemigordiopsis cf. luquensis and Colaniella aff. minima. This association corresponds to the Late Wuchiapingian (=Late Dzhulfian), a substage whose algae and foraminifera are generally little known. Contemporaneous limestones crop out in the middle part of the Episkopi Formation in Hydra, but they are rather commonly reworked in Mesozoic and Cainozoic sequences. The palaeobiogeographical affinities shared by the foraminiferal markers of Greece, southeastern Pamir, and southern China, are very strong (up to the specific level), and are congruent with the Pangea B reconstructions. To cite this article: E. Skourtsos et al., C. R. Geoscience 334 (2002) 925–931.     

PALEONTOLOGY

正20141596 Liu Yunhuan(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China);Shao Tiequan Early Cambrian Quadrapyrgites Fossils of Xixiang Boita in Southern Shaanxi Province(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,35(3),2013,p.39-43,3 illus.,20 refs.)     

GEOCHEMICAL EXPLORATION

正20141719 Chen Zhijun(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China);Chen Jianguo Automated Batch Mapping Solution for Serial Maps:A Case Study of Exploration Geochemistry Maps(Journal of Geology,ISSN1674-3636,CN32-1796/P,37(3),2013,p.456-464,2 illus.,2 tables,10 refs.)     

MICROPALAEONTOLOGY

正20140962 Chen Fenning(Xi’an Institute of Geology and Mineral Resources,Xi’an710054,China);Chen Ruiming Late Miocene-Early Pleistocene Ostracoda Fauna of Gyirong Basin,Southern Tibet(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,87(6),2013,p.872-886,6illus.,56refs.)     

PETROLOGY

正1.IGNEOUS PETROLOGY20142008Cai Jinhui(Wuhan Center,China Geological Survey,Wuhan 430205,China);Liu Wei Zircon U-Pb Geochronology and Mineralization Significance of Granodiorites from Fuzichong Pb-Zn Deposit,Guangxi,South China(Geology and Mineral Resources of South China,ISSN1007-3701,CN42-1417/P,29(4),2013,p.271-281,7illus.,     

ENVIRONMENTAL GEOLOGY

正20141205Cheng Weiming(State Key Laboratory of Resources and Environmental Information System,Institute of Geographic Sciences and Natural Resources Research,CAS,Beijing 100101,China);Xia Yao Regional Hazard Assessment of Disaster Environment for Debris Flows:Taking Jundu Mountain,Beijing as an     

PROSPECTING EXPLORATION

正20141266Fan Chaoyan(Guangdong Provincial Key Laboratory of Mineral Resources and Geological Processes,Guangzhou 510275,China);Wang Zhenghai On Error Analysis and Correction Method of Measured Strata Section with Wire Projection Method(Journal of