贵州省泥堡金矿床矿体类型及其形成机理的新认识

根据贵州省西南部泥堡金矿床深部勘探成果,开展其矿床的矿体类型及其形成机理的综合研究,取得新认识如下:(1)矿区的主矿体不是层控型,而是断控型。断控型矿体的单个矿体规模大,厚度、品位较稳定,而层控型金矿的单个矿体规模小,厚度及矿石品位变化大;(2)虽然矿床的形成受到多种因素控制,但构造、地层及其有利岩性是关键的控制因素,尤其是断裂构造因素。F1逆冲断层既是导矿构造又是容矿构造,本矿床最大的金矿体就赋存于F1断裂破碎带中的减压扩容带,即断层破碎带变宽及断层面变缓部位。这两点新认识对区域找矿具有一定指导意义。     

甘肃玛曲大水金矿田控矿因素及主矿体特征对比分析

大水金矿田由大水、贡北、格尔托3处大、中型金矿床组成,经过30年巨量探矿工程的投入和持续有效的勘查与研究,整体达到了详查程度,累计查明金资源量约130 t,为典型矿床对比研究提供了理想基地。通过大水金矿田赋矿地层岩性、控矿断裂构造、成矿侵入岩等控矿因素的对比分析认为：大水金矿田赋矿地层岩性以中三叠统马热松多组灰岩为主;控矿断裂、成矿容矿脉岩及其所赋存矿体的规模,以大水特大型金矿明显优于贡北、格尔托中型金矿,大水金矿主要以NWW向压扭性主干断裂与近SN向放射状张性断裂的交汇部位控制厚富主矿体,贡北以EW向、格尔托以NNW与NE向断裂的交汇部位控制主矿体的分布;中酸性岩体及其派生的酸性岩脉与金成矿关系密切,容矿花岗闪长岩（斑）岩脉及其蚀变方解石大脉在陡倾断裂破碎带中的集中分布,往往指示厚富金矿体的赋存地段。通过3个矿区主矿体的规模、品位、资源量分布等特征的对比分析可以看出,主矿体的规模、品位以大水较贡北、格尔托为大、为富,大水、贡北、格尔托金矿的主矿体资源量分别占矿区的75. 62%、78. 51%和79. 58%,且由普查到详查,主矿体资源量占比有所变化,如大水金矿由70. 59%增加到75. 63%,贡北金矿则由88. 24%降低为84. 16%。     

西秦岭早子沟金矿控矿断裂形成演化

甘肃早子沟金矿床位于西秦岭地区,其成矿作用与断裂构造活动及中性岩脉的侵位关系密切,但成矿前期构造控矿作用研究相对较为薄弱。开展早子沟金矿的控矿断裂构造特征及其与金矿化的关系研究,可为分析矿床成矿机制、进一步开展地质找矿工作提供指导。早子沟金矿区主要发育4组不同方向的控矿断裂,根据断裂的相互切割关系推测,NW向断裂形成最早,SN向和NE向断裂次之,近EW向断裂形成最晚。矿区金矿体主要赋存于断裂破碎带中,金矿化及其展布特征显示,NE向断裂控制的矿体成矿早,矿体规模最大;受近EW向断裂控制的矿体发育两期矿化,矿化强度高。结合区域大地构造演化及断裂构造活动与金成矿作用关系分析,认为区域性的夏河–合作断裂构造带控制了早子沟金矿床的产出,早子沟矿区内不同方向的次级断裂多期次的活动叠加控制了金矿体的产出;推测早子沟金矿床两阶段的断裂活动控制了两阶段的金矿化作用,从而建立了早子沟金矿控矿构造的形成与演化模式。认为矿区下一步勘查工作重点应放在NE向断裂深部和近EW向断裂控制的缓倾斜矿体,尤其是近EW向断裂与其他控矿断裂交汇部位,是寻找叠加矿化富矿段的有利找矿地段。     

胶东望儿山金矿成矿构造分析和成矿预测

通过井下现场调查、构造编图,提出望儿山金矿区控矿构造型式为压扭性断裂构造系统之菱形结环式构造.矿区构造控矿规律表现为:矿体在剖面上呈特征的"S"型,矿体规模受制于构造规模,在倾向方向上矿体呈平行近等距产出,矿体间距多在60m±;矿化在垂向上具有明显的分段富集规律,共包括3个富集段,大体上矿体富集区间垂直距离180-26...     

湘东北万古地区金矿床成矿构造特征的初步研究

万古地区金矿床的成矿作用受到区域构造成矿的控制,矿区的断裂构造已经成为燕山中晚期金矿的定位构造.矿区北西西向断裂大部分是控矿、容矿构造,北东向断裂构造对矿脉的破坏作用有一定的影响,属成矿期后断裂构造.勘探线剖面图揭示了万古地区金矿床构造成矿具有金矿体侧伏特征、金矿体等距产出特征、金矿构造成矿作用多期性特征.冷家溪群是金的矿源层,万古金矿区的构造成矿作用是主要成矿作用,金矿化是剪切带长期活动的结果.从万古金矿、鲁源洞金矿、大洞金矿矿脉在走向和倾向的产出形态可以看出,富矿体都产出在构造张性扩容空间内.控矿层间破碎带中不同类型构造重叠部位是最有利的赋矿构造.     

山东省焦家矿区深部超大型金矿床及其对“焦家式”金矿的启示

通过三年的地质勘查研究,发现了山东焦家矿区深部105吨特大型金矿床,圈定了89个矿体,归并为4个矿体群,其中Ⅰ-1号主矿体沿焦家断裂主裂面分布。焦家矿区共探获金矿资源储量230多吨,成为世界级超大规模金矿床。通过焦家深部金矿床和浅部金矿床对比研究,揭示了新的金矿成矿规律:浅部金矿床和深部金矿床之间为无矿间隔或弱矿化带;金矿床矿体厚大部位在剖面上产于焦家断裂由陡变缓转折点下部;焦家带金矿床构成了沿"一条构造带、二段矿化富集带、三层矿化蚀变带"产出的矿床模式。通过同位素年龄测定,焦家断裂断层泥的K-Ar年龄为131.05～123.53Ma和48.57～41.18Ma,早期指示断裂构造的主要形成期与金矿的主成矿期同步;晚期金矿的同位素年龄略晚于郭家岭花岗岩年龄,略早于崂山花岗岩年龄,位于伟德山花岗岩年龄值高峰段内,说明伟德山花岗岩岩浆活动是导致"焦家式"金矿成矿的直接因素。     

胶东地区前孙家-洼孙家断裂南段构造控矿规律及找矿研究

胶东西北部是我国重要的金矿聚集区,矿床主要受断裂构造控制。前孙家-洼孙家断裂是研究区内主要控矿断裂。依据该构造南段前孙家、金华山两个金矿的岩石、构造、矿体分布、矿化蚀变等特征,对两矿区的构造控矿型式、构造控矿规律进行了探讨,认为该区成矿热液活动具有多期性。成矿预测表明前孙家矿区4号脉的深部可能存在盲矿体,2号脉在深部有一定的延伸;金华山矿区1号脉的下盘可能存在与1号脉平行的雁列脉矿体;1号脉、2号脉在深部应有交汇,可作为重点找矿位置。     

河南公峪金矿区断裂控矿作用分析

公峪金矿区以构造蚀变岩型金矿为主,已发现金矿脉２０余条,预测远景储量５０ｔ以上,找矿前景良好。根据构造控矿的观点,从区域构造应力场转换入手,分析了区域构造演化与成矿作用的关系,对矿区内空矿作用进行了论述,找出正是由于控矿断裂的规律性活动导致了工业矿体具有等间距性、侧列性及侧状性等分布规律,控矿断裂的规模及演化控制了矿体的规模及演化;阐述了构造活动与矿体定位的关系。     

大坪金矿床主矿体控矿构造与矿化富集规律

大坪金矿床位于哀牢山金矿带南部,为研究其规模最大的V1-2-3号矿体的控矿构造和矿化富集规律,本文研究总结了矿体地质特征,对矿体的多级控矿构造及力学性质进行剖析,采用矿体垂直纵投影图对厚度、品位及其剩余值、趋势值等值线图进行分析。研究结果表明:金矿主要受三级断裂构造控制:红河-哀牢山深大断裂控制整个金矿成矿带;小新街断裂为导矿构造;小新街断裂的次级断裂带为容矿构造。在构造应力机制发生转换的大规模成矿时期,矿区受到由顺时针旋转变为逆时针旋转的构造应力场作用,控矿断裂性质由左行压扭性转变为张性。构造应力场严格控制了矿体的空间位置、规模、形态、矿体厚度与品位变化特征。成矿流体运移方向为北西-南东方向,在多期、多阶段成矿作用下,形成层状分布矿化富集带。研究厘定了V1-2-3号矿体共有3个矿化富集带,包括7个矿化富集中心,其侧伏方向为北西-南东方向。矿化富集中心大多形成于构造引张的部位,形成透镜状富厚矿体;在构造闭合的地方,矿脉变薄、品位降低,形成贫化带或无矿段。     

新疆北山金窝子金矿田断裂构造控矿作用及控矿构造格架

金窝子金矿田位于新甘交界的哈密地区,是北山地区最为重要的金矿田之一,其大地构造背景处于哈萨克斯坦—准噶尔板块与塔里木板块交汇部位东北缘的北山裂谷;断裂构造是矿田内最为重要的控矿因素.文章对矿田内主要的控矿断裂构造特征和断裂构造控矿规律特征进行了研究,F210韧脆性剪切断裂带为矿田内的主干断裂,该断裂的逆冲破碎带为210金矿床的直接控矿构造,控制了蚀变岩型金矿化的发育,由逆冲剪切产生的叠瓦式逆断层不含矿,而近SN向缓倾斜构造控制了210金矿床石英脉型矿化的发育:由F210韧脆性剪切断裂逆冲作用在金窝子岩体内形成的近SN向高角度追踪张性断裂控制了金窝子金矿床石英脉型矿体的形态、产状及成矿元素的分布;在对构造控矿作用研究的基础上,建立了矿区的控矿构造格架.     

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.     

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.     

Quaternary stresses revealed by calcite twinning inversion: insights from observations in the Savonnières underground quarry (eastern France)

Calcite samples were extracted both from the rock matrix and the superficial coating of a karstified fault plane of an underground quarry, located in the eastern border of the Paris basin. The karstification is dated as Quaternary. Analysis of mechanical calcite twinning reveals that only the calcite matrix has also undergone a compression trending WNW that can be attributed to the Mio-Pliocene alpine collision. Both coating and matrix have undergone a strike-slip regime with σ₁ roughly trending north–south, that could correspond to the regional present-day state of stress, a strike-slip compression rather trending NNW, modified by local phenomena. To cite this article: M. Rocher et al., C. R. Geoscience 335 (2003).     

HYDROGEOLOGY

正20141756 Chen Ruige(Mathematical College,China University of Geosciences,Beijing100083,China);Zhou Xun Numerical Simulation of Groundwater Level Fluctuation in a Coastal Confined Aquifer with Sloping Initial Groundwater Level Induced by the Tide(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(7),2013,p.1099-1104,6 illus.,16 refs.) Key words:confined water,groundwater level     

METAMORPHIC PETROLOGY

正20141408 Cai Jia(Institute of Geology,Chinese Academy of Geological Sciences,Beijing100037,China);Liu Fulai Petrogenesis and Metamorphic P-T Conditions of Garnet-Spinel-Biotitebearing Paragneiss in Danangou Area,Daqingshan-Wulashan Metamorphic Complex Belt(Acta Petrologica Sinica,ISSN1000-0569,CN11-1922/P,29(7),     

SERIALS

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GEOPHYSICAL EXPLORATION

正20142386An Guoying(China Aero Geophysical Survey and Remote Sensing Center for Land and Resources,Beijing 100083,China)Application of Satellite Remote Sensing in Regional Hydrogeological Investigation:Taking Cenozoic Strata in Wenquan Sheet(1∶250 000)of Karakoram Range as an Example(Geosci-     

QUATERNARY GEOLOGY & GEOMORPHOLOGY

正20141016An Chengbang(Key Laboratory of Western China’s Environmental Systems,Ministry of Education,Lanzhou University,Lanzhou 730000,China);Zhao Yongtao Lake Records during the Last Glacial Maximum from Xinjiang,NW China and Their Climatic Impli-     

PETROLEUM GEOLOGY

正20141538 Cao Qing(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China);Zhao Jingzhou Characteristics and Significance of Fluid Inclusions from Majiagou Formation,Yichuan Huangling Area,Ordos Basin(Advances in Earth Science,ISSN1001-8166,CN62-1091/P,28(7),2013,p.819-828,7 illus.,3 tables,43 refs.)     

GEOCHEMISTRY

正20142002 Wei Hualing(Institute of Geophysical and Geochemical Exploration,Chinese Academy of Geological Sciences,Langfang065000,China);Zhou Guohua Element Content and Mineral Compositions in Different Sizes of Soil in Tongling Area,Anhui Province(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,32(11),2013,p.1861