天津蓟县硼矿床锰方硼石矿物的硼同位素研究

天津蓟县硼矿床是世界上唯一的沉积环境特殊的锰方硼石型硼矿床。矿床呈层状产于震旦系碳酸岩泥灰质岩系中 ,矿石呈鲕粒状或球粒状集合体 ,是成因条件极其特殊的矿床类型。含矿岩系为中元古界高于庄组沉积岩系 ,含矿岩性由下而上依次为含锰白云岩、页岩互层→含锰白云岩、泥硅质岩 ,夹锰方硼石矿层→含锰页岩、白云岩→厚层白云岩→薄层白云岩→厚层白云岩 ,锰方硼石矿体在矿层中呈断续相连的团块状或透镜状分布。硼矿物成分简单 ,只有锰方硼石一种矿物 ,锰方硼石矿体呈透镜状断续成层分布 ,东西延长达 30km。东部矿段以锰方硼石为主 ,向西部渐变为菱锰矿。矿石有块状和斑点状。块状矿石全部由球粒状锰方硼石集合体组成 ,w (B2 O3 ) >2 0 % ,最高可达 4 2 %以上。斑点状矿石中锰方硼石集中呈球粒状集合体分布于泥质白云岩中 ,w (B2 O3 ) <7%。首次研究了该硼矿床锰方硼石的硼同位素组成 ,δ11B值为 +6 7‰～ +14 9‰ ,均为正值 ,并且东部大峪矿段的硼同位素值低于西部柏树沟矿段的硼同位素值 ,表明该硼矿床的成矿元素属于海水来源。由于锰方硼石的微量元素组成难以与蒸发岩比较 ,且富含F、Ba、Sn热液富集的元素和Co、Ni、Cr、Ti基性岩浆岩元素以及与Fe、Mn大洋结核有关的元素组分 ,因此锰方硼石应属于     

辽东裂谷硼铁矿床地质及成矿作用

辽东硼铁矿床是一处类型独特的超大型矿床。文章对该矿床的地质特征、矿石物质组成、矿床稀土元素和稳定同位素特征及矿化时代进行了研究。研究表明,该矿床的成矿作用主要表现为海底热水沉积成矿,区域变质混合岩化作用对矿床进行了强烈的叠加改造,使硼铁进一步富集而形成工业矿床。     

翁泉沟含铀硼铁矿床综合开发利用研究与对策

翁泉沟含铀硼铁矿中硼(B2O3)储量约占我国总储量的一半,矿床经勘探后一直没有很好得到利用。在综合利用资料积累与地质研究基础上,认为影响矿床利用的因素主要为矿石分解状况。研究认为矿床中硼镁铁矿-磁铁矿和硼镁石-磁铁矿两种主要类型矿石中绝大部分为可利用的变质后期热液作用产生的硼镁石-磁铁矿型矿石。这种热液作用形成的矿石是有规律可寻的。为达到综合利用的目的,有必要按不同类型矿石重新圈定矿体,根据不同矿体中硼镁铁矿分解率指标,选择两种不同综合利用方案。     

辽宁翁泉沟含铀硼铁矿床矿石特征及热液分解作用

辽宁翁泉沟含铀硼铁矿中硼（B2O3）储量约占我国总储量的一半,矿床经勘探后一直没有得到很好利用。在综合利用资料积累与地质研究基础上,认为影响矿床利用的因素主要为矿石分解状况。研究认为矿床中硼镁铁矿-磁铁矿和硼镁石-磁铁矿两种主要类型矿石中绝大部分可利用的为变质后期热液作用产生的硼镁石-磁铁矿型矿石。这种热液作用形成的矿石是有规律可寻的。为达到综合利用的目的,有必要按不同类型矿石重新圈定矿体,根据不同矿体中矿物组分,选择不同的综合利用方案。     

智利卡门铁矿床磁铁矿元素地球化学特征及矿床成因意义

卡门铁矿床位于智利著名的中生代铁-铜-金成矿带内,本文根据矿石组构和矿物共生特征将卡门铁矿床成矿期次划分为硅化阶段、磁铁矿阶段、黄铜矿阶段和晚期热液脉阶段4个阶段。卡门铁矿床磁铁矿有两种类型:含硫化物块状磁铁矿、与阳起石共生磁铁矿,以含硫化物块状磁铁矿为主。电子探针研究表明,该矿床与阳起石共生磁铁矿的Fe O_T含量略高于含硫化物块状磁铁矿;整体上来看,磁铁矿的Fe O_T与Si O_2、Al_2O_3、Mg O呈负相关关系。激光剥蚀电感耦合等离子体质谱(LA-ICP-MS)微量元素成分分析表明,卡门磁铁矿轻稀土元素亏损,重稀土元素富集且分馏程度相对较大;Co、Ni元素含量高,与夕卡岩型磁铁矿较为接近,但Ni/Co比值变化较大,与夕卡岩型有明显差异,说明卡门磁铁矿与典型夕卡岩成因的磁铁矿存在一定差别,同时较高的Ni/Co比值反映了其成因与深源物质有关。卡门铁矿床磁铁矿Ti O_2-Al_2O_3-(Mg O+Mn O)三角图表明该矿床具有热液交代特征,与夕卡岩相关;(Ca+Al+Mn)-(Ti+V)成因判别图也显示该矿床有夕卡岩型铁矿特征,但同时也与IOCG型矿床有一定的相似性,这进一步证明卡门铁矿床可能并非典型的夕卡岩矿床,其成矿可能与铁氧化物铜金(IOCG)型成矿过程岩浆热液活动密切相关,这与卡门铁矿床处于智利IOCG成矿带的地质事实一致。     

黔北地区浣溪铝土矿床地球化学特征及指示意义

黔北地区浣溪铝土矿床探明资源量超过2000万吨,达到大型矿床规模。研究表明:浣溪铝土矿床为产于黄龙组灰岩古侵蚀风化面或韩家店组黏土岩、砂页岩等侵蚀间断面之上的沉积型大型铝土矿床。矿石以一水硬铝石为主,黏土矿物、铁矿物、钛矿物次之。矿石主要化学成分为Al_2O_3、SiO_2、Fe_2O_3、TiO_2、LOI(烧失量)、S,此6种组分占矿石总组分的95%～98%。矿体中Sr、Cu、B、Ga、Sr、Ba、V、Cr、Ni、C等元素变化规律及其Sr/Cu、B/Ga、Sr/Ba、V/Cr和Ni/Co比值特征显示,矿床主要形成于炎热潮湿的古气候条件,矿床沉积的古地理环境兼具海相、海陆过渡相和陆相沉积特征,相对开放的氧化沉积环境利于成矿。     

西藏当雄错盐湖卤水中硼的来源研究

当雄错盐湖为大型硼矿床。大气降水、地表径流和地下径流以及蚀源区岩石是当雄错盐湖卤水中硼等稀有、稀散元素的三个来源途径。本文通过国标法(GB/T8538-2008)、电感耦合等离子光谱法(ICP-AES)、电感耦合等离子质谱法(ICP-MS)对当雄错硼的这三个来源分别进行元素地球化学研究,发现:1大气降水对当雄错B_2O_3的年估算输入量约为0.05×10~(-3)t~1.5×10~(-3)t,与地表径流和地下径流893t相比可以忽略不计;2河流对当雄错B_2O_3的贡献量最大,其中湖南岸的3条河流B_2O_3的年估算输入量达10个水源的95%,这3条河流的地球化学特征与热泉马尔作相同,B同位素δ~(11)B值也与热泉马尔作相同。说明当雄错地表径流和地下径流中的B_2O_3主要来自热水;3当雄错湖周蚀源区岩石主要为二叠纪,白垩纪岩石与第四纪碳酸盐粘土与钙华。其中二叠纪与白垩纪岩层中B_2O_3的含量较中国东部同类岩石低,不是当雄错B_2O_3的主要来源。第四纪碳酸盐粘土与钙华B_2O_3含量较高,高于世界碳酸盐岩与中国东部富泥碳酸盐岩。碳酸盐粘土稀土元素分布模式与已报道的热水湖相沉积的白云岩相同,都是中稀土富集,Dy的正异常,说明碳酸盐粘土是主要受热水影响。当雄错碳酸盐粘土是热水湖相沉积的一个典型实例。综上可知,热水是当雄错硼的主要来源。这一研究不仅为探索盐湖硼的成因提供重要依据,也为扩大寻找硼酸盐矿床指明方向。     

吉林老岭大横路式热水沉积叠加改造型钴矿床

大横路式钴矿床位于辽吉元古宙裂谷带中部的老岭金、多金属成矿带中 ,是国内近年来发现和查明的新类型钴矿床。该类矿床产于古元古代老岭群富硼、碳千枚岩夹石英岩 (硅质岩 )建造之中 ;矿体由含碳绢云千枚岩、含电气石绢云千枚岩、石英岩、电英岩组成 ,呈层状、鞍状产出 ,产状与围岩一致 ;矿石中钴呈独立矿物硫钴镍矿、辉钴矿、方钴矿和含钴黄铁矿等产出。通过对矿床层控特征、矿体产状与矿石组合、矿石沉积组构、容矿岩石地球化学、热水沉积岩、稀土元素及同位素组成等几方面的研究 ,证明该矿床具有明显的海底热水沉积成因特征 ,矿床受后期热液改造叠加强烈。从而提出大横路式钴矿床为海底热水沉积 -热液叠加改造型矿床     

硼矿床的成因类型、分布、应用及找矿远景

【研究目的】硼是重要的非金属关键性矿产资源，也是新技术产业重要的工业原材料。中国硼矿资源储量2400万t，位列世界第五，中国既是硼矿生产大国，也是硼矿进口大国，82%的硼矿来自国外。研究硼矿床的成因、分布及其找矿远景，是解决中国硼资源大量依赖进口的有效途径，有利于保障国民经济的持续发展。【研究方法】本文通过搜集公开资料，对硼矿的成因类型、分布及应用等进行了归纳总结。【研究结果】硼矿按成因可划分为火山沉积型、沉积变质型、矽卡岩型、现代盐湖型、地下卤水型、海相蒸发沉积型等六类；主要分布于环太平洋沿岸及地中海沿岸，如土耳其的凯斯特莱克、埃梅特、比加迪奇等矿床，美国的克拉默矿床，玻利维亚的乌尤尼盐湖等，储量占全球储量的90%左右。【结论】其中火山沉积型硼矿床占全球总量的75%左右，品位最低可达25%(B₂O₃)，是全球重要的矿床类型；现代盐湖型硼矿床约占20%，品位8%～30%(B₂O₃)不等；沉积变质型硼矿床是中国重要的硼工业矿床，矿石品位11%(B₂O₃)。根...     

中条山地区铜矿峪斑岩铜钼矿床电气石硼同位素特征

硼同位素由于其稳定性,可以作为很好的源区示踪工具。本次采用LA-MC-ICP-MS方法对铜矿峪变斑岩型铜钼矿床绢英岩化带中的电气石硼同位素进行了原位测试。获得δ11 B值为-21.1‰~1.1‰,数据分布显示为相对富轻硼的(-16‰~-14‰)和相对富重硼的(-1.5‰~1.5‰)两个峰值。结合前人硼同位素储库比对分析,铜矿峪铜钼矿床显示了大陆热液系统的硼同位素组成特征。铜矿峪铜钼矿床富轻硼的峰值特征很可能由火山岩围岩提供。相对富重硼峰值很可能是铜矿峪成矿花岗闪长斑岩和花岗闪长岩提供。铜矿峪铜钼矿床的电气石硼同位素特征相对于其他斑岩型铜矿床及IOCG矿床明显更富集轻硼,显示了该矿床成矿中有大量陆壳的硼加入。     

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