胶东金矿集中区金矿成矿年代学研究

对不同研究者采用蚀变矿物Rb Sr、K Ar和Ar Ar法 ,流体包裹体Rb Sr等时线法 ,石英Ar Ar法和矿石矿物 (黄铁矿 )Rb Sr等时线法等多种同位素定年方法获得的胶东金矿集中区金矿成矿年龄数据进行了方法适用性研究和应用选择 ,筛选后的成矿年龄集中于 15 3 8～ 80 6Ma。综合考虑与金矿床有密切时空关系的花岗岩类侵入体及脉岩的K Ar、Ar Ar及U Pb (SHRIMP)年龄 ,确认胶东金矿集中区金矿主成矿期年龄为 (115± 10 )Ma ,金 银 多金属矿成矿期年龄为 (85± 5 )Ma ,分别为中生代早白垩世晚期 (K21)和晚白垩世早期 (K12 )。     

含金剪切带蚀变特征及其与金成矿的关系——以新疆天格尔金矿带为例

含金剪切带剪切变形过程中构造、流体-岩石相互作用导致系统内组分的迁移和再分配，这些过程控制着含金剪切带内蚀变特征及其金的成矿作用。在含金剪切带脆-韧性变形域内，成矿层次从深到浅矿石类型由蚀变糜棱岩型向石英脉型过渡，矿床成因类型由韧性剪切带型向蚀变破碎带型过渡，是主期剪切成岩成矿过程中不同时空演化阶段的产物。     

广东河台糜棱岩带蚀变岩型金矿床的地球化学研究

产于麋棱岩带的河台金矿是一种新的金矿类型。地质及地球化学研究表明主要控矿因素有:①矿源层(含金建造)——提供金的来源;②混合岩化及花岗岩岩浆热液作用——促使金发生活化转移;③韧性剪切带——提供了导矿通道及容矿空间。矿床形成于中温(250℃)、中深(573.5×10~5Pa)的条件。成矿流体富含HCO_3-及CO_2,并具Na~+>K~+>ca~(2+),HCO_2~->C1~->F~->ΣS,CO_2>CH_4的特点。介质从早到晚由中性到弱碱性,氧逸度f_(o2)为10~(-37)-10~(-39)。矿床是多阶段长期演化发展的产物,区域变质作用,动力变质作用,混合岩化作用过程中变质热液起着主导作用,海西—印支期断裂重熔岩浆热液活动使金局部富集。在此认识基础上,提出了河台金矿的成矿模式。     

Water migration coefficients of chemical elements in the hypergenesis zone

The contents of basic salt components in the continental discharge related to weathering processes were calculated taking into account the atmospheric transfer of soluble salts from the ocean and their supply from anthropogenic sources. Real water migration coefficients characterizing the mobility of chemical elements in the hypergenesis zone were calculated on the basis of these data. It has been shown that the water migration coefficient directly depends on the solubility of basic minerals that are stable in the hypergenesis zone.     

Climate shifts and coastal changes in a geological perspective. A contribution to integrated coastal zone management

This Special Issue deals with the impact of climate change on western European coastal systems. Notwithstanding the inherent problems of studying geological data in terms of climate shifts, the results show that on the meso- and the macroscale of time, climatic forcing is a major drive for coastal change. However, its impact is largely influenced by other factors. Sediment availability plays a dominant role in the evolution of coastal systems and it can be considered one of the most important thresholds at the land-ocean interface. Sea-level changes are expected to have a significant impact on most European coasts. There is particular concern for the tidally influenced flats and marshes, and for those coastal areas known to have already a net sediment deficit and to be threatened by erosion. Areas where isostatic uplift has countered sea-level rise until now, are expected to become subject to coastal erosion in the near future under an accelerated sea-level rise scenario. The sensitivity and vulnerability of coastal systems to climate shifts is shown to be largely controlled by storm magnitude and fetch. A particular case of vulnerability is the impact of tsunamis. Finally, the consequences of human interference have been demonstrated in many cases. The implementation of geoscientific studies for rational, comprehensive and cost-effective strategies on a regional or national level of integrated coastal zone management is reviewed.     

老挝爬奔金矿金矿化及其围岩蚀变过程元素迁移

根据水岩反应理论,通过对矿化蚀变岩与围岩的对比分析,对爬奔金矿围岩在矿化蚀变过程中的元素迁移规律进行了分析研究,结果表明在金矿化热液蚀变过程中,不同元素带入带出程度不同,具有一定的迁移规律,主要带入元素为Au、Hg、As、W,元素W的带入说明含矿热液可能与深部岩浆有关,地球化学W异常为后期找矿提供了新的指示性线索.     

A contribution to the pseudoleucite problem

A study has been made of the differences produced in leucites by different methods of cooling charges, in the system NaAlSiO₄-KAlSiO₄-SiO₂-H₂O, consisting of leucite and silicate liquid. The results indicate that the ion exchange reaction in the system is so fast that metastable leucite-analcite solid solutions may be produced between leucite crystals and hydrous glass.     

雪峰隆起带金矿成因新析

本文以地球科学基础学科的基本知识和矿床实例首次论述了雪峰隆起带内板岩、变质砂岩等浅变质的区域变质作用不能使岩石中的金活化迁移富集成矿;断裂构造在动力变质过程中本身并不成矿,断裂破碎带的地层中金只是带内金矿体金金属量的0.123%;流体包裹体测定的金矿成矿温度主要区间在200～300℃,说明雪峰隆起带岩金矿床不是地下水热液成因;金矿床的一些矿石矿物、伴共生组分、微量元素、同位素地球化学等特征与花岗岩类岩浆岩的相似性也说明了两者间的成因关系;重磁资料推断地表无岩浆岩出露的岩金矿床下部有大面积的隐伏岩体。以上论述和排除法均说明雪峰隆起带上岩金矿床成因类型是岩浆热液矿床。     

Eukaryotization of the early biosphere: A biogeochemical aspect

The synthesis of data on the paleobiology and geochemistry of the Archean and Proterozoic and the ecology, biochemistry, and comparative genomics of living organisms provides a means for reconstructing the development of biological complexity on the subcell, organism, and ecosystem levels. The conditions and time of the origin of oxygenic photosynthesis, eukaryotic cells, and multicellular animals were determined. These evolutionary events had a profound influence on the global biogeochemical cycles, sedimentogenesis, and climate of the Earth. Irreversible geochemical changes in the biosphere and the biochemical evolution of living systems are described as complementary processes. A decrease in hydrogen concentration in the early biosphere, an increase in oxygen concentration in the ocean, and changes in the bioavailability of metals (Fe, Ni, Co, V, W, Cu, Mo, etc.) known as enzyme activators were considered as key factors of eukaryotization. The reasons for variations in the availability of the metals in the biosphere were distinguished. The continuity of life was maintained owing to the preservation of the functionality of archaic metabolism types through the compartmentalization of biochemical reactions and the complication of cellular metabolic networks. The metabolic cascades of living cells probably recapitulate this prolonged evolutionary process. The exhaustion of abiogenic hydrogen sources stimulated the symbiosis of hydrogen-producing and hydrogen-consuming prokaryotes and the involvement of simple hydrogen-bearing volatile compounds (CH₄, NH₃, H₂S, and, finally, H₂O) as a substrate for life, which eventually predefined the chemical composition of the terrestrial atmosphere strongly dominated by nitrogen and oxygen as by-products of exchange reactions. The oxygenation of the ocean diminished the mobility and bioavailability of some metals that had served as the earliest enzyme activators. The evolutionary response to this process was the formation of mechanisms of extraction, accumulation, and the retention of ancient activator metals (e.g., Fe, W, and Ni) in the cell and in the ecosystem, as well as the active involvement of new metals (e.g., Mo, Cu, and Zn). Oceanic biota became the main concentrator and reservoir for these metals. The appearance of eukaryotic cells, the increasing role of heterotrophy, an increase in biodiversity, the complication of trophic relationships, the acceleration of the cycle of biophile elements, and other features of the biosphere eukaryotization were to large extent a response to the narrowing of the geochemical basis of life. A pivotal point in the prolonged process of biosphere eukaryotization was a series of glaciations at the end of the Proterozoic (750–540 Ma) and the active oxygenation of the ocean, which enabled the global expansion of eukaryotic organisms.     

某化工厂废液CODCr在包气带中的迁移规律及数值模拟

为揭示精对苯二甲酸工厂废液在粉土包气带中的吸附、降解和迁移规律、迁移速度,通过静态吸附、厌氧降解以及土柱淋滤实验,确定土壤水化学参数及溶质反应参数,结合数学模型和模拟软件进行研究.实验结果为:包气带粉土对废水CODCr的吸附可以用线性方程表示,分配系数为0.155cm3/g;对CODcr的降解系数λ为0.009 7d-1;CODCr在土柱中迁移的纵向弥散度为0.15cm.通过HYDRUS-1D软件模拟CODCr迁移曲线,拟合值与实测值对照结果良好;使用该模型对CODCr浓度的运移预测表明,包气带厚为17m时,CODCr浓度为4 000mg/L时以1m定水头持续淋滤情况下经过11.63a可到达潜水面.     

剪切带型金矿中金沉淀的力化学过程与成矿机理探讨

剪切带型金矿是一种重要的金矿床类型,有关该类型金矿的成因问题已开展了大量研究,但对于剪切带中金的沉淀析出机制和成矿过程仍存在较大争议,对于赋矿部位的构造属性与矿床关系的研究尚显薄弱。对此笔者整理分析了近年来国内外有关剪切带型金矿的研究进展,并结合我国胶东金矿的研究实例,运用断层阀和力化学理论分析发现,无论是脆性还是韧性剪切带,无论是脉型还是蚀变岩型金矿,其成矿的关键部位均与构造应力集中而导致的脆性破裂(特别是R、T、R’破裂的产生)和碎裂作用以及(多期)岩体侵位密切相关,并且脆性破裂所导致的压力骤降从而引发流体闪蒸的力化学过程可能是造成金沉淀析出成矿的有效机制,其中多期岩体侵位所提供的流体是成矿的物质基础。此外,从国内外实例可以看出,剪切带中的脆性破裂不仅发生于脆性或脆韧性构造域,也可以发生在较深层次的韧性构造域中,尽管韧性域中产生脆性破裂的原因还不十分清楚,但这可能是韧性剪切带成矿的关键机制之一。最后,综合岩体、流体、剪切带三者对成矿的耦合作用,文中提出剪切带型金矿的成矿机理为:(多期)岩体侵位-热液活动-构造剪切-应力集中-脆性破裂(碎裂)产生-压力骤降-流体闪蒸-元素(金)析出,如此循环往复方可形成大型剪切带型金矿。     

含金剪切带型金矿及苏北变质岩区金的找矿方向

含金剪切带型金矿的成矿作用与剪切变形作用密切相关。本文在总结含金剪切带型金矿地质特征的基础上,分析和总结了苏北变质岩区成矿地质条件与金的矿化信息,认为苏北地区可能存在破碎带型和含金剪切带型两类金矿,并提出寻找含金剪切带型金矿的新的找矿方向。     

剪切带断层泥特征及其在胶东金矿床研究中的应用

剪切带断层泥是中低温热液蚀变的产物。研究表明,断层泥的形成演化与剪切带水-力行为间存在强烈的作用与反馈。断层泥的粒度分布、矿物组成以及孔渗结构受断裂带构造变形和流体作用的控制。同时,由于具有组成和结构上的特性,断层泥可以通过增强岩石各向异性和储存或释放流体而改变断裂带剪切强度和流体压力。以胶东金矿集中区为例,讨论了剪切带构造变形、流体输运-反应与断层泥形成演化的耦合作用,及其对剪切带流变学行为及金矿化形成和分布的影响。     

Vertical migration of residual magma in the upper zone of the Bushveld Complex

Summary Migration of residual liquid can potentially affect the textures and mineral compositions in layered intrusions, but is difficult to conclusively demonstrate. In the Upper Zone of the Bushveld Complex a metabasaltic xenolith forms a locally impermeable horizon, which acted as a barrier to vertically migrating residua. Increased Ab content in plagioclase, and K₂O and Zr in whole-rock analyses in the anorthosite directly below the xenolith, compared to the same horizon along strike of the xenolith, demonstrate trapping of residual liquid and/or fluid beneath the xenolith.Comparison of Cu/Ni and Cu/S ratios of the mineralised anorthosite in the normal sequence and below the xenolith suggests that these are primary magmatic sulphides which crystallised within the anorthosite and are not derived by sinking of dense interstitial sulphide liquid originally associated with the overlying magnetite layer or introduced hydrothermally.

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Vertikale Migration von Restmagma in der Upper Zone des Bushveld-Komplexes

Zusammenfassung Die Migration von Restschmelzen kann Texturen und Mineralzusammensetzungen in geschichteten Intrusionen beeinflussen, jedoch ist es schwierig, dies eindeutig nachzuweisen. In der Upper Zone des Bushveld-Komplexes bildet ein metabasaltischer Xenolith einen lokal undurchlässigen Horizont, der für vertikal migrierte Residuen als Barriere fungierte. Erhöhte Ab-Gehalte in Plagioklas, sowie erhöhte K₂O und Zr-Werte in Gesamtgesteins-Analysen in Anorthosit direkt unterhalb des Xenolithen-verglichen mit der Zusammensetzung des gleichen Horizontes in Streichen des Xenolithen-weisen auf Konzentration von Restschmelzen und/oder Fluiden im Liegenden des Xenolithen hin. Der Vergleich von Cu/Ni und Cu/S Verhältnissen der mineralisierten Anorthosite in der normalen Abfolge mit denen unterhalb des Xenolithen zeigt, daß es sich hier um primäre magmatische Sulfide handelt, die innerhalb des Anorthosits kristallisierten. Diese Sulfide lassen sich nicht auf das Absinken von dichter Sulfidschmelze, die ursprünglich mit den überlagernden Magnetit-Bändern in Zusammenhang standen, und auch nicht auf hydrothermale Zufuhr zurückführen.

     

Hydrogeochemical prospecting of gold in an alpine bald mountain zone

The investigation was conducted within highly and moderately separated highlands and high plateaus where glaciers, stone streams, solifluction, and glacial and fluvio-glacial deposits are widely developed. A capping of Miocene basalts remains in the divides over the Au ore deposits and their oxidation zones. Young water-filled fractures traverse the ore-bearing structures and control the direction of the glacial and river valleys, as well as the location of the lakes, springs, and icings.Gold occurs in small- to average-sized sulphide-Au-quartz veins and in a sulphidized black shale series of Precambrian and Paleozoic age. Both mechanical and hydromorphic dispersion of Au are exhibited clearly in the highlands. The latter is due to the processes of modern oxidation of the Au-bearing sulphide minerals. The anomalies of Au in streams and small lakes are related to supra- and sub-ice waters. In the water of streams Au is present in three forms; colloidal, dissolved, and sorbed. Gold in colloidal form comprises the most ample and contrasty anomalies. The truly dissolved Au is more local and manifests itself close to the source of the stream. Gold sorbed on suspended matter is evident because of a significant removal from the source into the solution. Migration of Au and formation of long (up to 2.5 km) and contrasty dispersions in waters of low dissolved solids is favoured by the presence of organic matter and argillaceous and ferruginous suspensions as well as other sorbents. The anomalies of Au in water either coincide with anomalies in stream sediments over mineralized zones or indicate new mineralized areas not reflected in stream sediments.     

Basalt weathering and trace elements migration in the boreal Arctic zone

Chemical weathering of basalts in the Putorana Plateau, Central Siberia, has been studied by combining chemical and mineralogical analysis of solids (rocks, soils, river sediments and suspended matter) and fluid solution chemistry in order to quantify CO₂ consumption and to assess the major factors controlling basic rock weathering under permafrost-dominated taiga climate. The chemical status of  40 major and trace elements (TE) in pristine boreal rivers and interstitial solutions of permafrost soils has been investigated using in-field ultrafiltration procedure. This revealed strong relationships between concentration of TE and that of major inorganic components of colloids, i.e., Fe or Al. Decomposing plant litter and permafrost thawing are considered important sources of most major and trace elements in Arctic rivers during summertime.     

The role of glaciations in the biosphere

Glaciations took place in five long intervals of the geologic history, called glacioeras: Kaapvaal (Late Archean), Huronian (Early Proterozoic), African (Late Proterozoic), Gondwanan (Paleozoic), and unfinished Antarctic (Late Cenozoic). The glacioeras were similar in structure, duration, and dynamics of evolution. They consisted of three to six glacioperiods including several discrete glacio-epochs. The glacioeras lasted ~ 200 Myr. They started with small regional glaciations, which expanded, reached intercontinental sizes, and then quickly degraded. There were serious differences between the Precambrian and Phanerozoic glacioeras. A series of ecologic crises related to numerous glacial events led first to abiotic and then to biotic factors. Glaciations caused extinction and stagnation of the Earth’s biota, the appearance of bionovations and new biota, and acceleration of evolution processes. Thus, the glacioeras were the turning intervals of the biosphere evolution.     

A contribution to the theory of variation diagrams

Harker diagrams and other ternary weight per-cent diagrams distort genetic trends by changing their slopes. They can not be readily used to discriminate between rival hypotheses. Two theorems have been proven which show the desirability of using certain types of ratios, instead of per-cent values, for comparisons. It is suggested that, when it is desired to discriminate between rival hypotheses, or to determine the exact variation between components, weight per-cent comparisons be discontinued (wherever possible) in favour of molar ratio comparisons in which one of the components (the divisor) is a constant. Variation diagrams of this type offer reliable discrimination between rival hypotheses, and yield the true relationship between variables in every case. An example involving crystal fractionation of olivine and pyroxene from a basic sill is developed in detail, and other potential uses are mentioned. This technique is completely general and is not restricted to chemical components, or to any scale of system, or to any field of study, providing certain essential conditions are fulfilled.