刚果（金）HAUTSHABA铜钴矿床地球化学特征及成因分析

HUATSHABA矿床位于著名的中非刚果(金)铜钴矿带上,主要产于罗安群矿山组(R2)地层中;成矿硫元素来源于海水;围岩的形成在新元古代,低温海相环境,并有细菌参与;矿床的形成经历了一个大型而广泛的热液系统;矿床的形成分为早期成岩成矿阶段、成岩期成矿阶段、晚期成矿阶段和造山成矿作用、表生氧化阶段四个成矿阶段;综上,矿床为典型的沉积型铜钴矿床。     

刚果(金)HAUTSHABA铜钴矿床地球化学特征及成因分析

HUATSHABA矿床位于著名的中非刚果(金)铜钴矿带上,主要产于罗安群矿山组(R2)地层中;成矿硫元素来源于海水;围岩的形成在新元古代,低温海相环境,并有细菌参与;矿床的形成经历了一个大型而广泛的热液系统;矿床的形成分为早期成岩成矿阶段、成岩期成矿阶段、晚期成矿阶段和造山成矿作用、表生氧化阶段四个成矿阶段;综上,矿床为典型的沉积型铜钴矿床。     

刚果（金）KOLWEZI铜钴矿床地质特征及成因分析

KOLWEZI铜钴矿位于刚果(金)-赞比亚铜钴矿带,卢菲利弧外部褶皱推覆构造带西北缘,KOLWEZI复式推覆体上。该矿床主要受Mines亚群及卢菲利造山运动D1阶段褶皱、逆冲推覆、断层及层间断裂控制。矿体呈层状,矿石主要为它形粒状结构,层状、浸染状构造,矿石矿物和脉石矿物按生成序次可以分为四个组合。结合毗邻KOLWEZI的类似矿床的地球化学研究及中非铜矿带的研究成果,认为KOLWEZI铜钴矿床的成矿过程经历了三个成矿期次,其中同成岩期成矿是形成KOLWEZI铜钴层状矿体的主要期次,同造山期矿化使先成层状矿体中的硫化物矿物发生活化、再沉淀,同造山构造活动一定程度上塑造了KOLWEZI铜钴矿床如今的产出状态。分析认为,KOLWEZI铜钴矿应属同成岩层状沉积矿床。     

中条山古元古代沉积岩容矿型铜钴矿床钴来源及富集过程

赋存在石墨片岩和大理岩内的山西中条山沉积岩容矿型铜钴矿床,其矿化类型为细脉浸染状和热液脉状,与中非铜矿带的钴矿床非常相似。本文以关键金属钴作为主要研究对象,综述了中条山矿集区钴矿成因研究近年来取得的重要进展。获得以下主要认识：(1)钴富集形成热液脉状矿化发生在造山抬升阶段,时间为～1.82Ga,而不是在沉积成岩阶段直接富集成矿;(2)黄铁矿原位Fe-S同位素揭示硫化有机质页岩是钴成矿的重要矿源层;(3)蒸发岩在造山作用过程中形成的高温、高盐、强氧化性流体是钴释放-迁移的关键介质;(4)热液白云石化导致流体pH升高和石墨片岩“褪色”反应导致流体氧逸度降低促进含钴硫化物的沉淀。基于上述认识,建立沉积-变质两阶段钴富集过程模型解释赋存在变沉积岩内的钴矿成因,它不同于经典的沉积岩容矿型层状铜钴矿床成矿模型。     

刚果（金）加丹加省KABARE铜钴矿床地质特征及成因分析

KABARE铜钴矿区位于刚果(金)加丹加铜矿带大型推覆构造带的北部.该矿床地质工作及研究程度极低,铜钴矿体受地层、后生逆掩挤压及断裂构造复合控制,尤其在逆掩断层带中,罗安群和恩古巴群接触带附近的碎裂岩带,形成蚀变明显的铜钴赋矿岩性组合.通过区域地质背景、矿床地质特征分析,认为该矿床经历了早期成岩成矿阶段,后期多期构造热液叠加富集,晚期次生氧化及表生风化淋滤改造多个阶段,为层状多因复控型氧化矿床,受岩性-构造复合叠加控制明显.     

刚果(金)加丹加鲁苏西铜钴矿床S、C、O、Sr同位素特征及矿床成因

鲁苏西铜钴矿床位于刚果(金)加丹加铜钴矿带,是该区域典型层控铜钴矿床。该矿床的矿石类型依据氧化程度可分为硫化矿和氧化矿。野外地质观察和区域资料分析表明,硫化矿的成矿期可分为成岩早期和造山期,矿石矿物为黄铜矿、斑铜矿、硫铜钴矿和辉铜矿。氧化矿主要为铜钴硫化物在富水表生环境下淋滤而成。矿床的同位素数据分析表明:该矿床成岩期的硫化物为以生物还原作用为主,硫源来自元古宙海水,碳源以海相无机碳为主,放射性锶同位素与基底物质有关;造山期硫化物生成以热化学还原作用为主,成矿流体来自蒸发盐的溶解,硫源来自早期硫化物再活化和蒸发盐溶解,碳氧同位素表明成矿流体与围岩发生了强烈的缓冲反应。综合分析表明,蒸发相的海水为鲁苏西铜钴矿富集和成岩早期成矿提供了有利条件,造山期改造和表生期氧化对矿床品位的富集影响明显。     

刚果(金)加丹加省堪苏祁铜-钴矿床地质特征及成因探讨

堪苏祁铜钴矿区位于刚果（金）加丹加省南部的沙巴型铜钴矿亚带北西延部分的转折端。该矿床地质工作及研究程度极低，铜钴矿体受罗安群地层、韧脆性剪切及断裂构造控制，特别是钴明显受韧脆性剪切强变形带控制。罗安群上岩性段以富钴为主，同时也富铜，钴、铜兼有，下岩性段则富铜贫钴，矿体呈似层状或透镜状产出。根据矿床地质特征，初步认为该矿床经历了早期沉积成岩成矿阶段-后期多期热液构造叠加富集-晚期次生氧化改造多个阶段，为复合成因的层控改造矿床，矿区内铜矿早期是受沉积型砂页岩地层的控制，然而，钴矿的形成主要是受后期构造的控制。     

“石碌式”铁氧化物_铜(金)_钴矿床成矿模式初探

石碌铁矿是中国著名的以富赤铁矿为主的大型矿集区,除铁矿外,还共生或伴生铜、钴、镍、银、铅、锌等金属矿产和白云岩、石英岩、重晶石、石膏、硫等非金属矿产。文章通过对石碌铁矿的成矿地质条件和控矿因素的再认识,结合成矿时代的探讨和矿床地球化学资料,认为该矿床严格受层位(主要为青白口纪石碌群第6层)、岩性(钙镁质矽卡岩等)、构造(复式向斜、层间滑脱带、片理和劈理)和/或岩性界面等控制;并强调石碌铁矿所经历的成岩成矿作用与海西期-印支期花岗岩侵位所导致的伸展构造(变质核杂岩构造?)密切相关,而岩浆热扰动则是导致深部含矿热卤水形成、上升并渗滤、交代矿源层的重要因素。最后,作者将该矿床称之为"石碌式"热液铁氧化物-铜-(金)-钴矿床,初步将其归属为IOCG(即热液铁氧化物-铜-金-钴)型层控式钙镁质矽卡岩矿床,并初步构建了该类型矿床的成岩成矿模式。     

刚果（金）Kimin铜钴矿床地质特征与成矿模式

Kimin铜钴矿床位于刚果（金）加丹加铜钴多金属成矿带北西部,是该带内代表性超大型矿床。文章在剖析Kimin矿床成矿地质背景、矿体特征、控矿因素及找矿标志的基础上,探讨和厘定了矿床成因类型,建立了矿床成矿模式。结果表明,Kimin矿床铜钴矿体呈层状、板状及薄膜状产出,总体呈EW—近EW向展布,明显受控于地层岩性、近EW向层间断裂、氧化淋滤等作用;Kimin矿床由浅部至深部矿物由铜、钴次生氧化物逐渐转变过渡为原生硫化物;其成矿作用主要经历了原始沉积铜钴矿化、热液改造铜钴叠加富集及表生氧化淋滤富集等三个阶段,矿床成因类型为“沉积-热液改造型铜钴矿床”。     

非洲中南部卢弗里安地区Cu-Co矿床研究进展

对非洲中南部卢弗里安地区Cu-Co矿床的大量研究成果进行了总结,概括了典型矿床的区域地质背景、岩石地层划分,较为系统地分析了成矿带中矿床的地质特征和矿床成因。得到①罗安群成岩年龄为765~735Ma,这也是同生沉积层状铜钴矿的形成年龄;②后期多阶段改造的主要成矿年龄为510~500Ma,主要受到卢弗里安时期复杂的逆冲推覆断裂和褶皱控制。     

全国地层委员会召开三届四次常委扩大会议

20 0 2年 7月 2 3日至 2 5日在北京香山饭店召开了全国地层委员会三届四次常委扩大会议 ,主要内容有 :1)关于 2 0 0 1年度全国地层委员会工作情况的汇报 (王泽九副主任 ) ;2 )“中国主要断代地层建阶研究”项目各课题组汇报研究进展情况及下步工作计划安排 ;3)审查修改已完成的《中国区域年代 (地质年代 )表》说明书 (初稿 ) ;4 )审查已编制完成的《中国地层典》(中文电子版 )。此次会议的会议纪要将在下期另行刊出。全国地层委员会召开三届四次常委扩大会议@边步     

U.S.G.5. II Revisited*

Based on the most recent compilation of analytical data, a new set of “usable values” is calculated for six of the best known silicate rock reference samples produced by the U.S. Geological Survey. The latest version of the “best laboratories” method is described and results are compared with other recently published values.     

Deinocephalians of the U.S.S.R.

The deinocephalian pelvic girdle, of general pelycosaurian structure, is useful in systematic diagnosis. In primitive Russian deinocephalians, two contrasting pelvic patterns are recognized, one light, thin-walled, narrow, and of V-shaped cross-section, and the other massive, thick-walled, wide, and of U-shaped cross-section. The former is characteristic of two families of lightly- built, mobile land carnivores, the Eotitanosuchidae and the Brithopodidae. The Eotitanosuchidae are more primitive and pelycosaur-like, while the Brithopodidae show more variation, and specializations of large size, shallower acetabulum (related to mobility?), and re-enforcement of a weak pubic symphysis by additional processes. The massive type of pelvis characterizes large, heavily built herbivorous animals of the family Estemmenosuchidae. In general pelvic structure, the Estemmenosuchidae resemble the South African anteosaurs and tapinocephalians and the Russian tapinocephalians. In detail, however, they show a more primitive stage of evolution, overlaid by characteristic specializations which relate them more closely to the advanced Russian forms than to those of South Africa. Three new genera are erected, Biarmosaurus, fam. Eotitanosuchidae; Chthomaloporus, fam. Brithopodidae; and Molybdopygus, fam. Estemmenosuchidae. One specimen formerly referred to Deuterosaurus Yefremov 1954, and five formerly included in the type of Brithopus Yefremov 1954 are referred to Molybdopygus. The more primitive deinocephalians are from Yezhovo in the Ocher District, Perm Province, while more advanced forms are from Isheyevo, in Tataria, where-therocephalians and other South African elements are also found. It is therefore concluded that the Ochersk beds are older than those of Isheyevo and must be dated to zone I of Yefremov's system. — N. Hotton III.     

图文并茂的《陡山沱期生物群》最近出版

由中、美两国古生物学家袁训来、肖书海、尹磊明、安德鲁·诺尔 (美国科学院院士 )、周传明和穆西南共同撰写的《陡山沱期生物群——早期动物辐射前夕的生命》一书最近由中国科技大学出版社出版、发行。该书分为三章 ,用一百八十余幅彩色图片配以文字系统地介绍了湖北三峡庙河、皖南蓝田与贵州瓮安三地的“庙河生物群”、“蓝田植物群”和“瓮安生物群”的地质背景与生物群面貌 ,其中包括发现时轰动全球的生物胚胎化石。陡山沱期生物群发生在“雪球事件”之后、埃迪卡拉生物群和寒武纪大爆发出现之前 ,目前国外尚未发现与之同期的多细胞生物…     

Eozoic complexes of the U.S.S.R.

Soviet geologists consider the Precambrian to be divided into two groups — Archaean and Proterozoic; but such a division is unsatisfactory. A major unconformity separates Proterozoic volcanic and sedimentary formations from an underlying sequence that contains two supergroups of supercrustal formations. The oldest of these is unanimously considered to be Archaean. Rocks of that supergroup play an essential part in the composition of the Baltic, Ukrainian, Aldan and Anabar Shields and of the ancient fold belts of the East-European and Siberian platforms.Distinctive features in the composition, tectonic structure, metamorphism and metallogeny of Archaean complexes lead to the conclusion that they were formed in specifically mobile areas, different from geosynclinal areas.The other supergroup of high-grade metamorphic rocks has no clear place in the accepted two-fold stratigraphic scheme of the Precambrian, and it is considered sometimes to be Archaean and sometimes to be Early Proterozoic. We propose restoring the forgotten name “Eozoic” for that supergroup. Eozoic complexes are characterized by peculiarities of composition and inner structure, which signify changes in the tectonic regime of the earth at the lower and upper boundaries of the Eozoic Supergroup. These peculiarities give grounds for distinguishing the Eozoic Supergroup as an independent stratigraphic division.The Stanovoy Complex of the southern part of the Aldan Shield is a stratotype for the Eozoic Supergroup. Many well-known stratigraphic subdivisions of the Siberian Platform (e.g., the Eniseiskaya, the Birusinskaya series and others), the Taratash Complex of the Urals, the Goranskaya and Shahdarinskaya series of the South-West Pamir, the Tikitch complex and Aulskaya series of the Ukrainian Shield, and in part the Belomorsky Complex of the Baltic Shield, as well as some others, are also Eozoic.The Eozoic complexes are characterized by the following specific features: only some supercrustal formations are typical for them; the small number of rock types which have a total thickness about 5–6 km; relatively monotonous mineral composition of the rocks; variable quantitative ratios of rocks; absence of contrasting marker beds; regional metamorphism and ultrametamorphism in the amphibolite facies; wide development of ultrametamorphic granitoids and migmatites; distinct tectonic differentiations of the basin of sedimentation.Dates determined by isotopic analyses, which mostly reflect the metamorphism of the deposits, fall predominantly in the range 2600–3100 Ma.