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1.
尹福光 《沉积与特提斯地质》2003,23(4):79-83
康滇地区裂谷作用已得到证实,但形成这种地堑地垒的格局有多种解释,以传统的地质力学分析为主。笔者借以热力学的自由热对流原理来加以论述：攀西巨厚的火山岩体在下覆异常地幔热作用下,发生自由热对流,引起热量散失,使地壳沉降与隆起不均衡,生成地堑地垒的格局。自由对流单元的侧向迁移,使盆地形成非对称性。 相似文献
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The garnet–muscovite (GM) geothermometer and the garnet–muscovite–plagioclase–quartz(GMPQ) geobarometer have been simultaneously calibrated underconditions of T = 450–760°C and P = 0·8–11·1kbar, using a large number of metapelitic samples in the compositionalranges = 0·53–0·81, = 0·05–0·24, = 0·03–0·23 in garnet, = 0·17–0·74 in plagioclase, and Fe = 0·04–0·16, Mg =0·04–0·13, AlVI = 1·74–1·96in muscovite on the basis of 11 oxygens. The resulting GM thermometeryielded similar temperature estimates (mostly within ±50°C)to that of the garnet–biotite thermometer, and successfullydiscerned the expected systematic temperature change of progradesequences, thermal contact zones and an inverted metamorphiczone. The resulting GMPQ barometer yielded similar pressureestimates (mostly within ±1·0 kbar) to the garnet–aluminumsilicate–plagioclase–quartz (GASP) barometer andplaced the aluminosilicate-bearing samples in the appropriatealuminosilicate stability fields. Application of the GMPQ barometerto thermal contact aureoles or rocks within limited geographicalareas confirmed the expected constant pressures that shouldexist in these settings. The random errors of the GM thermometerand the GMPQ barometer are estimated to be ±16°Cand ±1·5 kbar, respectively. When biotite or aluminosilicateis absent in metapelites, metamorphic P–T conditions maybe determined by simultaneously applying the GM thermometerand the GMPQ barometer. KEY WORDS: application; calibration; geobarometer; geothermometer; metapelite 相似文献
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中央造山带早古生代地体构架与高压/超高压变质带的形成 总被引：57，自引：2，他引：57
位于北中国板块群与南中国板块群之间的中央造山带是中国大陆一条十分醒目而又极其重要的巨型(长达5000km)构造带。中央造山带是经历了大致600Ma的活动历史,和泥盆纪、三叠纪的两次主要碰撞造山以及白垩纪以来的陆内造山过程而构筑成的典型的“复合造山带”。特别是巨型中央超高压变质带及其两期超高压变质作用的发现,揭示了中央造山带的形成还经历了板块会聚边界洋壳/陆壳深俯冲的两次壮观地质事件。位于中央造山带北部的“北中央早古生代造山带”具有“多地体、多岛弧”的地体构架和“多俯冲和多碰撞造山”的动力学作用。研究认为北中央早古生代多地体/岛弧群是冈瓦纳超大陆西侧(或西北侧)陆块/岛弧群的组成部分,其主要的证据是:1北中央寒武系—志留系的过渡性动物群性质反映早古生代古生物区系与始特提斯洋盆海水相通的古地理环境;2北中央诸多蛇绿岩带形成时代>500~540Ma(新元古代-奥陶纪)可作为始特提斯洋盆扩张时限的印证;3多岛弧带为北中央早古生代地体的陆缘增生带,形成于540~450Ma,岛弧带形成自南(外)而北(里)渐新的趋势表明与始特提斯洋盆相连接的弧前小洋盆逐级俯冲的特征;4北中央早古生代多地体/岛弧群的“弧/陆碰撞”及早古生代造山带的形成是中晚泥盆世(420Ma)冈瓦纳超大陆边部古特提斯洋盆初始扩张的产物。研究表明在500~440Ma形成的柴北缘-南阿尔金超高压变质带与始特提斯弧前小洋盆的俯冲继而地体陆壳的深俯冲有关。 相似文献
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Jean-Pierre Berger Bettina Reichenbacher Damien Becker Matthias Grimm Kirsten Grimm Laurent Picot Andrea Storni Claudius Pirkenseer Andreas Schaefer 《International Journal of Earth Sciences》2005,94(4):711-731
We present a general stratigraphic synthesis for the Upper Rhine Graben (URG) and the Swiss Molasse Basin (SMB) from Eocene to Pliocene times. The stratigraphic data were compiled both from literature and from research carried out by the authors during the past 6 years ; an index of the stratigraphically most important localitites is provided. We distinguish 14 geographical areas from the Helvetic domain in the South to the Hanau Basin in the North. For each geographical area, we give a synthesis of the biostratigraphy, lithofacies, and chronostratigraphic ranges. The relationships between this stratigraphic record and the global sea-level changes are generally disturbed by the geodynamic (e.g., subsidence) evolution of the basins. However, global sea-level changes probably affected the dynamic of transgression–regression in the URG (e.g., Middle Pechelbronn Beds and Serie Grise corresponding with sea-level rise between Ru1/Ru2 and Ru2/Ru3 sequences, respectively) as well as in the Molasse basin (regression of the UMM corresponding with the sea-level drop at the Ch1 sequence). The URGENT-project (Upper Rhine Graben evolution and neotectonics) provided an unique opportunity to carry out and present this synthesis. Discussions with scientists addressing sedimentology, tectonics, geophysics and geochemistry permitted the comparison of the sedimentary history and stratigraphy of the basin with processes controlling its geodynamic evolution. Data presented here back up the palaeogeographic reconstructions presented in a companion paper by the same authors (see Berger et al. in Int J Earth Sci 2005). 相似文献
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福建紫金山铜（金）矿与台湾金瓜石金（铜）矿的对比及其意义 总被引：5，自引：0，他引：5
福建西部的紫金山铜（金）矿与台湾北部的金（铜）矿其矿床（田）的很多特征十分相似，成矿的物理化学条件也很类同，表明其成矿作用在本质上是相同的，二者可以对比。依此为基础能够建立起一个综合性的有关火山／潜火山热液－斑岩成矿系到的两阶段三层模式。此模式环太平洋地区中、新生代火山活动地区类似床具有启示意义。 相似文献
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《Applied Geochemistry》2006,21(5):820-825
An analytical approach, based on the electron paramagnetic resonance (EPR) spectroscopy of Mn(II) in travertines, has been developed in order to obtain relevant information about the local inhomogeneity of calcite and about the thermodynamic conditions which control the formation of travertine deposits. This information is crucial to constrain the precipitation of travertine under different geochemical contexts. An empirical correlation between the spectral features and the zero-field splitting (ZFS) interaction has been established through numerical simulations of EPR spectra. The variability of the investigated parameters and the applicability of the method have been tested on several travertines from Central Italy. 相似文献
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The sulphidic tailings dumps at Matchless (Namibia) and Selebi-Phikwe (Botswana) are located in a similar semiarid environment
but have a contrasting mineralogical composition. The Matchless tailings are pyrite-rich, whereas the Selebi-Phikwe tailings
are dominated by pyrrhotite. Hydrochemical models are established with computer codes for water-balance, sulphide oxidation
rate and hydrochemical equilibrium calculations. The data input is based on detailed mineralogical, chemical and kinetic investigations
carried out on the core of boreholes drilled in 2000 and 2003. The oxidation of pyrrhotite proceeds at a much faster rate
than the oxidation of pyrite. The PYROX code, which is used for kinetic calculations, can take these differences into account
by applying different oxide-coating diffusion coefficients (D2) for pyrrhotite and pyrite. Humidity-cell testing is widely used to predict the post-mining composition of drainage water
in humid climates. However, the semiarid conditions at Matchless and Selebi-Phikwe only allow a minimal water flux within
the dump. Under such conditions, humidity-cell testing is likely to overestimate the seepage-water pH. This is suggested by
the hydrochemical equilibrium calculations for the post-mining period at Selebi-Phikwe, which predict a seepage-water pH about
one unit lower than the pH at the end of the 26-weeks humidity-cell testing period. The acidity of the seepage water can be
reduced by about half a pH unit, if an oxygen barrier below the evaporation zone is installed. A clay layer 0.5 m thick covered
by >1.5 m tailings represents the optimal design for a wet barrier. All three computer codes used for water-balance calculations
(HELP3, UNSAT-H and HYDRUS-1D), predict >85% average water saturation for such a layer, which diminishes the diffusion of
oxygen into the pile and production of SO4−2 and H+. The alternative design for a dry barrier consists of a vegetated silt layer 1 m thick on top of the tailings. This barrier
does not significantly influence the diffusion of oxygen although it reduces the net infiltration to ≤11 mm/year. 相似文献
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Leymeriellid ammonite faunas are described from northeast of Esfahan and the Khur area (Central Iran). The faunas comprise Leymeriella (L.) tardefurcata, L. (L.) germanica and L. (L.) acuticostata? as well as L. (Neoleymeriella) regularis, L. (N.) diabola and L. (Neoleymeriella) pseudoregularis?. The leymeriellids of Iran are closely related to faunas from northwest Europe, the Vocontian Basin and Transcaspia (Mangyschlak) and thus allow for biostratigraphic correlations, indicating the earliest Albian Leymeriella tardefurcata Zone with its superimposed L. acuticostata and L. regularis subzones. We suggest that the sudden appearance of common representatives of the genus Leymeriella in the northern and Central Iranian basins (Leymeriella acme) can be used as a useful proxy marker to define the base of the Albian Stage in Iran. 相似文献
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Investigations into zonation of estuarine invertebrates often indicate that animals living higher in the intertidal region have greater tolerance to effects of aerial exposure. Desiccation tolerances ofEurypanopeus depressus, a xanthid mud crab, were measured in the laboratory for both intertidal and subtidal populations to determine whether intertidal distribution is the result of either increased physiological resistance to drying or other factors. Initially, both populations had a similar percentage of body weight due to water, and at time of death both had lost a similar percentage of water. Desiccation tolerance increased exponentially with size. In laboratory experiments,E. depressus appears very susceptible to desiccation stress with loss of tactile response occurring at 30% depletion of body water. This crab may be able to avoid desiccation and survive in the intertidal zone by remaining in the shelter and moisture of oyster shells and mud at low tide. However,E. depressus may not be limited strictly by physical factors of its environment. Biotic factors such as behavior leading to predator avoidance are possibly more important components in limiting distribution. 相似文献
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Priv.-Doz. Dr. Dieter Richter 《International Journal of Earth Sciences》1967,56(1):543-561
Summary The Lower Devonian Meadfoot Group on the east coast of South Devon represents a typical shallow-water facies, comprising a variable sequence of mudstones, siltstones and sandstones or sandy siltstones. Many features of the deposits indicate the influence of strong water movements: cross-lamination, ripple-drift lamination, erosion channels and other washout structures.Current directions have been measured for all the sedimentary structures. Most of the clastic material was carried by lateral transport in this part of the Variscan geosyncline in directions both from W to E and E to W; a polarity of flow which may be explained as due to tidal influence. The direction of slumping indicates a sea floor sloping towards the south or south-west.An interesting feature is the presence of ball-and-pillow structures which is explained as essentially due to a sagging process.Many trails of organisms in the form of burrows occur in pelitic or silty deposits.
Zusammenfassung Die unterdevonischen Meadfoot Beds, die an der Ostküste von SE-Devonshire ausstreichen, sind in einer typischen Flachwasser-Fazies entwickelt. Sie bestehen aus einer Serie von Tonschiefern, Siltsteinen, Sandsteinen und Sand-Siltsteinen. Eine Reihe von Sedimentstrukturen beweist den Einfluß von stärkeren Wasserbewegungen auf das Ablagerungsbild, wie z. B. Schrägschichtung, Rippelstrukturen, Erosions-Rinnen und andere Auswaschungs-Strukturen.Die Strömungsrichtungen wurden an Hand der verschiedenen Sedimentstrukturen gemessen und ausgewertet. Sie zeigen, daß in diesem Teil des nördlichen Außenrandes der variszischen Geosynklinale der Transport des klastischen Materials vorwiegend durch E-W- oder W-E-Strömungen erfolgte. Diese Polarität wird durch Gezeiten-Wirkung erklärt. Subaquatische Rutschungen deuten auf einen Abfall des Meeresbodens während jener Zeit nach S oder SW.Ein interessantes Phänomen stellen ball-and-pillow-Strukturen dar, die auf komplizierte Sackungs-Bewegungen, vermutlich unter Mitwirkung thixotroper Vorgänge, zurückgehen und vielleicht durch Erdbeben ausgelöst wurden.Lebensspuren, wie Grab- und Borgänge, treten häufig auf, vorwiegend in pelitischem Material oder Siltsteinen.
Résumé Les Meadfoot-Beds, d'âge éodévonien, qui affleurent sur la côte orientale du Devonshire sud-oriental, présentent un faciès néritique typique. Ces assises sont constituées de schistes, d'aleurites, de grès et de grès aleuritiques. Les structures sédimentaires font valoir une eau fortement agitée pendant le dépôt des sédiments; ainsi on note des stratifications obliques, des ripples-marks, des sillons d'érosion et d'autres indices de taraudage.Le sens des courants a été déterminé à l'aide de différentes structures sédimentaires. Il démontre que dans cette partie du bord septentrional du géosynclinal varisque le matériel clastique était transporté surtout par des courants EW et WE. Cette polarité se laisse expliquer par les effets de la marée. Les glissements subaquatiques suggèrent une pente du fond marin vers le S ou vers le SW.Les structures «ball and pillow» présentent un phénomène intéressant, qui se laisse ramener à des tassements, qui vont probablement de pair avec des procès de thixotropie, et qui sont peut-être occasionnés par des tremblements de terre.Les traces de vie, telles que des pistes d'excavation ou de fouissement, sont nombreuses surtout dans le matériel pélitique.
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The Northwestern (Maghreb) boundary of the Nubia (Africa) Plate 总被引：1，自引：0，他引：1
A study of the present compressional deformation of the Northwestern (Maghreb) Nubia (Africa) margin is derived from the analysis of more than 20,000 km of seismic profiles. In the western part the compression is distributed in a large zone with on-land compression in Algeria, mainly strike-slip deformation on the Algerian margin and folds and strike-slip faulting in Eastern Spain. In the middle of the Algerian margin, around Algiers, the evidences of compression become more obvious. In this area a ridge trending N–S that is interpreted as a middle to late Miocene spreading center interacted with the transpressional margin that trends E–W. North of the location of the Boumerdes–Zemmouri earthquake the oceanic crust is deformed by blind thrusts up to 60 km from the coast. These thrusts are south dipping and with the northward dipping thrusts located onshore form a wedge that maybe a positive flower structure at a crustal scale related to the right-lateral transpression of the margin. In the eastern part of the Northwestern (Maghreb) Nubia (Africa) Deformed Belt, off eastern Algeria and Tunisia, the deformation is more intense but limited to the north by the continental slope. Large late Miocene Tortonian folds are cut by the Messinian erosional surface but the present deformation is also evident. It is suggested that the deformation with a double vergence may be followed up to the north of Sicily. After the docking (18 Ma) of the Kabylies to the Africa Plate, the crust has been thinned and the Algerian Basin opened during the middle-late Miocene with an E–W direction. From the late Miocene to the Present the margin has been rethickened by transpression and uplifted. 相似文献
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Liquid-liquid extraction and electrokinetic studies show that both the talc particles and the isooctane droplets are affected by the presence of hydrolysable metal species of Al(III) and Cr(III). The inherent lipophilicity of talc is unchanged by the hydroxo complexes of these metal species, while positive shifts in zeta potentials of talc and isooctane take place due partly to the strong adsorption of these hydroxo complexes. In the pH range where the hydroxide precipitates, the talc particles are rendered hydrophillic between the precipitation pH and the point-of-zero charge of the metal hydroxide. This hydrophile-lipophile transition of talc in the isooctane-water system relates to heterocoagulation among talc particles, isooctane droplets and hydroxide precipitates. 相似文献
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Comparative petrology and metamorphic evolution of the Limpopo (South Africa) and Lapland (Fennoscandia) high-grade terrains 总被引：1，自引：0，他引：1
L. L. Perchuk T. V. Gerya D. D. van Reenen A. V. Krotov O. G. Safonov C. A. Smit M. Yu. Shur 《Mineralogy and Petrology》2000,69(1-2):69-107
Summary ?Detailed studies of rocks from the Limpopo (South Africa) and Lapland (Kola-Fennoscandia) high-grade terrains were carried
out in order to reveal similar geological and thermodynamic conditions in their formation. Both complexes (1) are situated
between Archean greenstone belts, (2) are younger than the belts, (3) are bounded by crustal-scale shear zones, (4) have a
similar intrusive-like (harpolith) geometry, and (5) show similar reaction textures that reflect both breakdown and growth
of garnet in each high-grade terrain. Local mineral equilibria within the textures indicate their successive formation with
cooling of the granulite facies rocks. Some of the textures in the metapelites must have resulted from the following reverse
reactions: Grt + Qtz ⇌Opx + Crd and/or Grt + Sil + Qtz ⇌ Crd. Based on these data, both the decompression cooling P-T path and the near-isobaric cooling P-T path were deduced for each HGT. However the near-isobaric cooling P-T path is not a characteristic of the central zones of both complexes studied.
Similar structural framework of the high-grade terrains, similar morphologies (shapes of granulitic bodies), similar reaction
textures developed in metapelites, and similar shapes of P-T paths suggest similarity in geodynamic history of both complexes.
Received March 8, 1999; revised version accepted September 17, 1999 相似文献
Zusammenfassung ?Vergleichende Petrologie und metamorphe Entwicklung der hochgradig metamorphen Terrains von Limpopo (Südafrika) und Lappland (Fennoscandia) Eingehende Untersuchungen an Gesteinen aus den hochgradig metamorphen Terrains von Limpopo (Südafrika) und Lappland (Kola-Fennoscania) sollen m?gliche ?hnlichkeiten in den geologischen und thermodynamischen Bildungsbedingungen aufzeigen. Beide Komplexe sind Lokale Mineralgleichgewichte innerhalb der Texturen weisen auf ihre schrittweise Bildung w?hrend der Abkühlung der granulitfaziellen Gesteine hin. Einige der Texturen in den Metapeliten gehen auf folgende reversible Reaktionen zurück: Grt + Qtz ⇌Opx + Crd und/oder Grt + Sil + Qtz ⇌ Crd. Diese Daten erm?glichten es, sowohl den P-T Pfad der Abkühlung bei Druckentlastung sowie den fast-isobaren P-T Pfad der Abkühlung für jedes HGT zu ermitteln. Der fast-isobare P-T Pfad der Abkühlung ist jedoch kein Charakteristikum der Zentralzonen beider Komplexe. Ein ?hnlicher struktureller Rahmen der hochgradigen Terrains, ?hnliche Morphologien (Ausbildung der Granulitk?rper), ?hnliche Reaktionstexturen in Metapeliten und ?hnliche P-T Pfade weisen auf ?hnlichkeiten der geodynamischen Entwicklungsgeschichte beider Komplexe hin.
Received March 8, 1999; revised version accepted September 17, 1999 相似文献
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Ekaterina Kaneva Maria Lacalamita Ernesto Mesto Emanuela Schingaro Fernando Scordari Nikolay Vladykin 《Physics and Chemistry of Minerals》2014,41(1):49-63
The structure, structural disorder and chemistry of miserite from the charoite-bearing rocks of the Murun massif (Russia) and from alkaline-syenite pegmatitic rocks of the Dara-i-Pioz massif (Tajikistan) were investigated employing a combination of electron microprobe, single crystal diffraction and micro-Fourier transform infrared spectroscopy analysis. Chemical analysis of the sample investigated by X-ray diffraction evidenced that Dara-i-Pioz miserite has a greater REE concentration than Murun miserite (~0.22 vs. 0.05 apfu, respectively) and also contains Y (0.14 apfu), which is absent in Murun miserite. The occurrence of a band at about 1,600 cm?1 testified to the presence of H2O in miserite at hand. Structural analyses yielded average cell parameters of a = 10.092, b = 16.016, c = 7.356 Å, α = 96.60°, β = 111.27° and γ = 76.34°. Anisotropic structural refinement in space group P $\bar{1}$ converged at similar values for the analyzed samples (R ~3.4, R w ~3.8 %). An interesting feature shown by both the miserite specimen is the presence, revealed by difference Fourier analysis, of a disordered part of the structure. This turned out to be due to the flipping of the tetrahedra belonging to the isolated [Si2O7]6? diorthogroups, one of the two radicals (the other is [Si12O30]12?) characterizing the miserite structure. The sixfold and seven-vertex Ca polyhedra linked to the inverted diorthogroups show variation in coordination number with respect to those of the ordered structure. 相似文献
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Jean S. Kane Bombor Batjargal Dorj Erdenetsetseg 《Geostandards and Geoanalytical Research》2009,33(3):295-308
A report is presented on the recertification of two certified reference materials (CRMs) initially prepared and certified by the Central Geological Laboratory of Mongolia (CGL), namely serpentinite GAS and alkaline granite OShBO. Subsequent work done in collaboration with the International Association of Geoanalysts (IAG) followed the International Organisation for Standardisation (ISO) guidelines for certification (ISO Guide 35, 2006) more closely than had been possible originally. The certification protocol followed was that of the International Association of Geoanalysts (IAG). The recertification added to the number of elements that were certified for OShBO (from 21 to 30), but not for GAS (decreased from 15 to 12) because of the greater analytical difficulties posed by that sample matrix in meeting the more stringent metrological requirements for recertification. Further, the uncertainties for these values were established in accordance with the Guide to Measurement Uncertainty ; individual contributions of heterogeneity and bias are reported as appropriate for each of the certified constituents. Traceability of the certified values was demonstrated to the greatest possible extent, based on concurrent analyses of the matrix-matched existing CRMs, SW and GM, by all participating laboratories. The materials are now available from the CGL for use by laboratories in controlling data quality when analysing materials of similar matrices. 相似文献
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乌鲁木齐河源冰雪及多年冻土径流过程特征 总被引：7，自引：6，他引：1
在全球气候变暖背景下,乌鲁木齐河源自20世纪90年代中后期呈现出显著气温升高和明显降水增加趋势,乌鲁木齐河源区1号冰川及空冰斗山坡春季冰雪消融径流开始产流的时间有明显的推后趋势;同时径流结束、河道断流的时间也有不太显著的推后现象,其间接说明了高山区冰川及多年冻土融冻过程有了明显的消融季节推后特征.2000年以后春季径流明显大于20世纪80年代,其中冰川主要消融期径流变幅明显小于前期,空冰斗山坡夏季径流显著增大且变幅明显变大.分析认为,乌鲁木齐河源径流的这些变化,主要是河源区冬、秋季的明显升温,大气降水、季节性积雪融水和冻土活动层融冻过程变化等的反映. 相似文献