甲基卡式锂矿田控矿作用与深部找矿方向

锂是我国重要的战略性新兴关键矿产。位于青藏高原东缘的甲基卡锂矿是全球最大的硬岩型锂矿田,同时也伴生大量铍、铌、钽、铷及铯等稀有金属。隐伏花岗岩体的形态,花岗岩与伟晶岩关系,以及细晶岩型和伟晶岩型锂矿体(脉)的空间分布是认识锂成矿控矿作用的关键。本文以甲基卡锂矿田为研究对象,通过高精度重力测量,建立了隐伏花岗岩穹丘的三维模型,推断了花岗岩体的形态及延伸;同时还利用大地电磁测深和钻探验证,揭示了X03、309、134等超大型、大型锂等矿脉与二云母花岗岩的关系。提出了复式(多中心)花岗岩浆底辟穹隆、不混溶Li-F花岗质岩浆脉动式充填-交代以及半开放的剪张裂隙控制大(矿)脉的认识,探讨了以花岗岩细晶岩型锂矿为主体,并与伟晶岩型锂矿共存的成因。这对第四系覆盖程度高的地区的找矿具有重要指导意义。隐伏花岗岩株(枝)形成的多中心小穹窿周缘是找矿有利部位。对隐伏花岗岩体向北北西倾伏的推断、岩石组合特征(是否只有二云母花岗岩单一岩石类型)等的认识还需在矿田北部加强探深科学验证;对于甲基卡式稀有金属超常富集过程的问题还需要继续探索研究,以期深部锂矿找矿突破。     

四川甲基卡锂矿区二长花岗岩的地球化学、氢氧同位素组成及其地质意义

四川甲基卡锂矿床为超大型锂矿床,矿区南部呈岩株状产出的二云母花岗岩与稀有金属伟晶岩在时间、空间及成因上具有密切关系。通过对该岩体元素地球化学特征和氢氧同位素组成的研究,探讨了其在稀有金属成矿过程中的作用。研究结果表明,甲基卡二云母花岗岩为富硅、高钾、钙碱性、强过铝质S型花岗岩,其稀土总量较低,岩浆来源为三叠系西康群砂泥岩为代表的地壳物质的部分熔融,流体来源可能是岩浆水和变质水的混合水。岩体微量元素R型聚类分析显示,与稀有金属成矿最密切的元素为Li、Rb、Ti、W、Mn,而岩体稀有元素含量的变化规律指示岩体北侧成矿效率高于南侧,是下一步找矿工作的重点。综合地球化学、氢氧同位素及前人研究,认为花岗岩浆在底辟侵入过程中可能发生了不混溶作用,由此分离出的伟晶岩浆在运移过程中稀有金属得到不断富集,最终形成伟晶岩型稀有金属矿床。     

四川甲基卡地区花岗岩型稀有金属矿找矿规律及标志

四川甲基卡地区位于青藏高原东部扬子板块西缘巴颜喀拉地块,是我国重要的花岗岩型稀有金属矿成矿远景区,分布其中的甲基卡伟晶岩型稀有金属矿床是我国规模最大的固体锂矿床,形成了Li-Be-Nb-Ta等成矿系列。通过对甲基卡伟晶岩型稀有金属矿床成矿条件、含稀有金属伟晶岩脉分类、稀有元素矿物期次划分及产出特征、稀有元素品位变化规律及富集规律、矿床成因及找矿标志的分析研究,探讨了该区锂矿的成矿规律,总结出了寻找甲基卡式锂矿的一系列重要找矿标志,对矿床外围及区域其他相似地质条件地区找矿工作具有一定的指导意义。     

川西甲基卡伟晶岩型锂矿科学钻探(JSD- 1)岩芯Li- B- Fe- Nd同位素对稀有金属成矿作用的指示意义

甲基卡伟晶岩型锂矿位于青藏高原东部松潘-甘孜地体东南部,是我国最大的硬岩型锂矿,其成岩成矿机制至今仍有争议。为了深入认识甲基卡伟晶岩型锂矿床稀有金属超常富集的关键岩浆热液过程,研究团队基于甲基卡一号钻孔(JSD-1)岩芯开展全孔Li-B-Fe-Nd同位素地球化学研究。伟晶岩和二云母花岗岩较低的Nb/Ta、Zr/Hf值以及Li-Nd同位素表明甲基卡伟晶岩可能来源于马颈子二云母花岗岩深成岩体的岩浆结晶分异。JSD-1岩芯花岗岩和伟晶岩中电气石的硼同位素(δ¹¹B)在-9.5‰～-7.1‰之间,与世界上90%的花岗岩和伟晶岩中δ¹¹B变化范围一致。JSD-1岩芯电气石δ¹¹B与全岩Li含量的实验和模型模拟结果表明花岗质岩浆演化过程遵循平衡结晶模型,花岗质岩浆极端结晶分异不能达到熔体中锂辉石过饱和。JSD-1岩芯全岩的Fe同位素(δ⁵⁶Fe)变化范围为-0.12‰～0.38‰。δ⁵⁶Fe的显著变化反映了黑云母分离结晶、热液蚀变(电气石化)以及石榴子石堆晶等多阶段岩浆-热液过程的共同结果...     

四川甲基卡锂矿床花岗岩体Li同位素组成及其对稀有金属成矿的制约

四川康定甲基卡超大型锂矿是我国最大的硬岩型锂矿床之一,矿区中南部呈岩株状出露的二云母花岗岩常被认为是成矿伟晶岩的"矿源岩",对其开展Li同位素地球化学研究,对探讨矿区稀有金属的来源与演化具有重要意义.研究工作基于详细的野外地质调查,采用MC-ICP-MS方法对岩体锂同位素组成开展了研究.研究结果显示,岩体Li含量介于192×10-6~470×10-6,均值为309×10-6,δ7Li值介于-1.56‰~+0.90‰,均值为-0.24‰,与平均上地壳值基本一致,具有高Li低δ7Li的特征.δ7Li与Li、Rb、Ga、SiO₂及ε_Nd（t）不存在明显的相关性,岩体锂同位素组成反映了其形成时的源区特征,未受岩浆结晶分异作用和蚀变作用的影响.岩体岩石地球化学、同位素地球化学资料表明,岩浆来源以三叠系西康群砂泥岩的部分熔融为主,可能有部分深源物质的加入.此外,岩体Li同位素的变化规律表明伟晶岩的成矿流体来源于二云母花岗岩.岩体Li含量与Li同位素组合不仅可用来划分锂矿床类型,而且对稀有金属找矿具有一定的指导意义.      

甲基卡式稀有金属矿床的地质特征与成矿规律

甲基卡是中国硬岩型锂矿最集中的产地之一,近年来又发现了X03号(新三号脉)超大型矿脉,使得甲基卡矿田锂的储量有可能超过澳大利亚格林布什而位居世界前列。文章通过对甲基卡矿床的地质特征、成矿期次、矿石组构、矿石成分等资料的总结,对其典型矿脉、典型钻孔的系统研究,以及与典型硬岩型锂多金属矿床的对比研究,总结出甲基卡的矿床式特点。甲基卡式矿床以形成于印支晚期—燕山早期、定位于欧亚大陆与印度板块之间的穹窿构造隆起区、围绕成矿母岩发育区域性分带,但单一矿脉的分带性较差、含矿伟晶岩既可以顺层产出也可以近垂直切层产出(类似于"五层楼+地下室")、锂辉石等稀有金属矿物既有伟晶状又有细粒状产出的特点,是中国乃至于世界上最重要的固体锂矿床类型之一,具有极大的找矿潜力,无论是新三号脉本身还是甲基卡外围其他地区都是值得工作的区域。甲基卡矿床式稀有金属矿床的成矿规律可指导热穹隆伟晶岩田的矿产勘查工作,川西地区除了甲基卡矿田之外,也适用于石渠、马尔康、九龙等地的伟晶岩田,同时,对于整个青藏高原的东部及北缘印支运动后期与燕山期之初岩浆-构造-热穹隆发育地区寻找伟晶岩型稀有金属矿床具有参考意义。     

华南花岗岩型锂矿地质背景与成矿条件

华南是我国花岗岩型铌钽锂等稀有稀土金属矿产的重要产地,以花岗岩型、蚀变花岗岩型矿床类型为主,也有少量伟晶岩型矿床,主要分布在武夷、南岭和江南等地区.锂矿多呈弥散状产出,和钨锡铌钽铍铯等稀有金属矿共生.在前人工作的基础,本文对华南锂等稀有金属矿产资源的地质背景和成矿条件进行了分析和总结.研究表明,锂矿带的分布受大地构造的制约.华南锂等稀有元素成矿物质的堆积与富集发生在具有古老基底的成熟陆壳区,经历了多期构造-岩浆作用的改造与物质循环过程,致使锂矿等稀有金属矿产不断富集.高成熟度的地壳、高分异高演化的花岗岩、富含挥发分流体的交代蚀变是锂矿物质迁移富集和成矿的三大因素,锂矿床多产在造山带中的背斜轴部和两组大断裂的交汇处,锂矿体多赋存在复式岩体的晚期岩株和蚀变花岗岩以及伟晶岩脉中,出现在晚期岩体的顶部和边部.成矿集中在新元古代、晚奥陶世—早泥盆世、中—晚三叠世和晚侏罗世—早白垩世4个时期,尤以晚侏罗世—早白垩世时期的锂矿类型最多,规模最大,矿质最好.华南具有花岗岩型铌钽锂稀有金属成矿的良好条件,具有很好的找矿前景.     

湖南仁里稀有金属矿田地质特征、成矿时代 及其找矿意义

仁里稀有金属矿田位于幕阜山岩体西南缘,是华南地区重要的稀有金属矿产地之一。文章旨在通过对区域成矿条件、矿田地质特征、地球化学特征、成岩成矿时代与稀有金属成矿作用的综合分析,为矿田勘查设计乃至华南地区稀有金属找矿与研究提供理论依据。在矿田范围内对燕山期、武陵期花岗岩及每个矿区代表性伟晶岩进行了系统采样,开展了岩石化学成分分析,同时对矿田内二云母二长花岗岩及锂辉石伟晶岩分别进行了锆石U-Pb、白云母Ar-Ar同位素定年。研究表明:①多期造山与燕山期陆内活化是成矿的有利地质背景,多阶段伸展作用导致幕阜山地区多期大规模的多金属成矿作用发生;②矿田构造主要以NE(或NNE)向构造为主,复合改造NW向及近EW向构造,NE(或NNE)向和NW(或近EW)向构造呈现立交桥式的构造格局,控制了花岗岩和伟晶岩分布;③矿田内伟晶岩属极高分异、富硅、过铝质花岗质岩石,燕山期花岗岩属陆壳改造"S型"花岗岩;④幕阜山岩体由岩体内接触带往岩体外接触带(10 km),由黑云母伟晶岩→二云母伟晶岩→白云母伟晶岩→锂云母伟晶岩→锂辉石白云母伟晶岩过渡,形成了较完整的稀有金属演化序列:无矿化→Be→Be+Nb+Ta→Be+Nb+Ta+Li→Be+Nb+Ta+Li+Cs;⑤稀有金属成矿与构造岩浆时空演化、构造组合、特别是岩浆的分异程度密切相关,矿田内燕山期花岗岩年龄139.3～146.2 Ma,稀有金属成矿年龄为130.5～130.8 Ma。     

川西甲基卡伟晶岩型锂矿的“多层次穹状花岗岩席”控矿新理论——记“川西甲基卡锂矿科学钻探”创新成果

川西甲基卡伟晶岩型锂矿是中国大陆最大的硬岩型锂矿床。以揭示伟晶岩型锂矿深部结构和成因机制为目的的甲基卡伟晶岩型锂矿科学钻探工程(JSD)实施了一口3211.21 m(JSD-1)和两口各1000 m(JSD-2和JSD-3)的科学钻探,取得如下的创新性研究成果：(1)首次发现JSD-1中0～900 m深度的晚三叠世浊积岩经历中低压-高温巴罗-巴肯式叠加变质作用和穹状构造特征;(2)揭示JSD-1的100 m深度范围的含锂辉石伟晶岩存在,以及估算了在3211 m深度伟晶岩中的稀有金属丰度及成矿潜力;(3)利用锡石、铌钽矿和独居石的精确定年,确定JSD-1深部伟晶岩形成的两期岩浆-热液事件(210～204 Ma和193～192 Ma);(4)流体包裹体的碱性元素(Li、Na、K、Rb、Cs)和挥发性元素(B、As)的富集指示富锂伟晶岩高度结晶分异。利用JSD-1岩芯Li-B-Fe-Nd同位素示踪了岩浆的演化、流体出熔过程及成矿机制,揭示甲基卡伟晶岩型锂矿床的花岗岩岩浆演化过程中,岩浆结晶分异促进大量流体的出熔,从而在浅部形成钠长石锂辉石伟晶岩为主的矿体。这些结果不支持含锂伟晶岩是地壳深熔作...     

川西甲基卡和可尔因矿田稀有金属成矿特征差异性及成因探讨

四川西部是我国松潘—甘孜造山带的主体,区域内中—上三叠统分布极其广泛,其中陆陆碰撞壳源改造型花岗岩类不均匀集中侵入于该套地层中,并衍生出以锂为主的稀有金属花岗伟晶岩,最有代表性的是甲基卡和可尔因花岗伟晶岩型稀有金属矿田,目前在二者中均勘察出超大型锂矿床。矿化伟晶岩脉主要由富锂辉石的白云母-钠长石-钾长石型花岗伟晶岩脉构成,它们分布在离母岩-二云母花岗岩外围热接触变质的蚀变中—上三叠统沉积岩系中,和围岩侵入关系清楚,并对围岩均有不同程度的接触交代蚀变作用。鉴于这些共同点,长期以来,人们对这两个矿田成矿作用的认识和找矿思路统一用甲基卡矿田成矿模式来看待。但随着研究工作的不断深入,发现它们既有相似处,但也存在较大的差异。比如:两个矿田形成时的构造-岩浆环境、花岗伟晶岩产出的围岩岩性和蚀变作用、矿化伟晶岩脉的结构-构造、成矿矿物的多样性等方面各有其不同的特征,本文在分别概述各自特征基础上,对产生差异的原因做了初步分析,为提升川西花岗伟晶岩成岩成矿理论和开辟新的找矿方向提供新依据。     

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