Dissolved aluminium in interstitial waters of recent marine sediments     

Serge Caschetto  Roland Wollast 《Geochimica et cosmochimica acta》1979,43(3):425-428

Measurements of the concentration and vertical distribution of dissolved aluminium and silica, and of pH. in interstitial waters of recent marine sediments from the North Sea and the Mediterranean Sea were performed to evaluate the behaviour of aluminium during early diagenesis. The results suggest that thermodynamic equilibria alone do not control the concentrations of dissolved species in the system Al-Si-O₂-H₂O during early diagenesis. Rather, these concentrations are governed by dynamic factors involving mineral dissolution-precipitation reactions and diffusion.  相似文献   

Die Entstehung von Pyrit in rezenten Sedimenten des Piburger Sees     

Dr. Roland Psenner 《Aquatic Sciences - Research Across Boundaries》1983,45(1):219-232

The occurrence of pyrite (FeS₂) and iron sulfide in surficial sediments of Piburger See was compared with thermodynamic calculations based on chemical analyses of iron and hydrogen sulfide in the interstitial water. The area below 17 m, where black spots were found in the sediments, showed ion products (log K_FeS=a_Fe2·a_HS/a_H+) between?3.11 and ?4.01. In areas with no visible FeS concretions logK_FeS values were in the range of ?4.74 to ?5.77, thus thermodynamic calculations seem to be in accordance with the appearance of iron sulfide. Nevertheless pyrite framboids, composed by more than 1,000 single crystals, coul be found even in shallow parts of the lake. Therefore the formation of pyrite is assumed to occur in microniches (diatom frustules, testacean shells). Inside these microcompartments high concentrations of hydrogen sulfide are reached due to the anaerobic decomposition of organic matter, whereas iron and additional sulfur are supplied by the diffusion of ferrous iron and sulfate from the anoxic environment.  相似文献   

Normal faulting of the Daiichi-Kashima Seamount in the Japan Trench revealed by the Kaiko I cruise, Leg 3     

Kazuo Kobayashi  Jean-Paul Cadet  Jean Aubouin  Jacques Boulgue  Jacques Dubois  Roland von Huene  Laurent Jolivet  Toshihiko Kanazawa  Junzo Kasahara  Kin-ichiro Koizumi  Serge Lallemand  Yasuo Nakamura  Guy Pautot  Kiyoshi Suyehiro  Shin Tani  Hidekazu Tokuyama  Toshitsugu Yamazaki 《Earth and Planetary Science Letters》1987,83(1-4)

A detailed topographic and geophysical survey of the Daiichi-Kashima Seamount area in the southern Japan Trench, northwestern Pacific margin, clearly defines a high-angle normal fault which splits the seamount into two halves. A fan-shaped zone was investigated along 2–4 km spaced, 100 km long subparallel tracks using narrow multi-beam (Seabeam) echo-sounder with simultaneous measurements of gravity, magnetic total field and single-channel seismic reflection records. Vertical displacement of the inboard half was clearly mapped and its normal fault origin was supported. The northern and southern extensions of the normal fault beyond the flank of the seamount were delineated. Materials on the landward trench slope are displaced upward and to sideways away from the colliding seamount. Canyons observed in the upper landward slope terminate at the mid-slope terrace which has been uplifted since start of subduction of the seamount. Most of the landward slope except for the landward walls aside the seamount comprises only a landslide topography in a manner similar to the northern Japan Trench wall. This survey was conducted on R/V “Jean Charcot” as a part of the Kaiko I cruise, Leg 3, in July–August 1984 under the auspices of the French-Japanese scientific cooperative program.  相似文献   

The average molecular weight and shape of the “polymeric acids” found in Black Trona Water from the Green River Basin     

Roland E. Barden  Eugenia R. Logan  J.F. Branthaver  Kenneth E. Neet 《Organic Geochemistry》1984,5(4):217-225

Macromolecular organic material, called “polymeric acids”, has been isolated from Black Trona Water by exhaustive dialysis and characterized as the sodium salt in 0.10 M sodium carbonate, pH 10, by several physico-chemical methods. Analysis by gel filtration chromatography on Sepharose-CL 6B indicates that the “polymeric acids” are polydisperse and composed of species of relatively high molecular weight ( 4 × 10⁵, using proteins as standards). With this method, the range of molecular weights appears to be rather narrow. If “polymeric acids” are transferred from sodium carbonate, pH 10, into distilled water, selfassociation occurs and all species elute in the void volume. The weight-average molecular weight determined in 0.10 M sodium carbonate, pH 10, by the light scattering method is 1.7 × 10⁵. Sedimentation velocity analysis at 20°C with the analytical ultracentrifuge gives a value for S_20,w of 5.4 and the shape of the Schlieren patterns suggest a polydisperse sample with a relatively narrow range of sizes. Analysis of the molecular weight distribution by a sedimentation equilibrium method indicates that the range of molecular weights is 8 × 10⁴ to 2.1 × 10⁵. The partial specific volume ( ) of “polymeric acids” is 0.874 ml/g. Viscosity measurements yield a value for [η] of 2.5 ml/g, which indicates that the “polymeric acids” are compact (spherical or ellipsoidal) in shape.  相似文献   

Sur l'origine de la pyrite et des skarns du gisement,en contexte evaporitique,de Niccioleta (Toscane,Italie)     

Roland Déchomets 《Mineralium Deposita》1986,21(2):106-115

Résumé La métasomatose d'infiltration par des solutions chlorurées a formé le gisement de Niccioleta, entre 425°C-500 bars et 475°C-1000 bars. Les transformations des substrats (anhydrite, dolomie, micaschistes) révèlent les mécanismes mis en jeux, et l'évolution de la composition des fluides. Les variations de composition du solvant (XCO₂, XH₂O, XH₂S, fS₂, fO₂) expliquent le rôle prépondérant des roches «fluides», carbonates et sulfates, dans la métallogénie hydrothermale. Le transport de Fe est lié à une sous-saturation en Na, K et Ca d'un fluide évoluant à Cl constant. Son dépôt résulte de réactions avec des roches contenant ces éléments; leur dissolution provoque la précipitation du Fe, moins soluble que Na, K et Ca sous forme chlorurée. L'action des carbonates et des sulfates est double: Ca agit sur l'équilibre des chlorures dissous; CO₂, ou H₂S, sur le solvant. Les conséquences de la succession des transformations sont claires dans le cas du sulfate: un fluide «secondaire», s'écoulant d'une zone de dédolomitisation, riche en CO₂ et sous-saturé en silice, transforme l'anhydrite en pyrite; un fluide «primaire» forme de l'andradite. Le fluide originel, «primaire», est une solution aqueuse chlorurée (0,9 à 1,8 m NaCl), réductrice, acide, chargée en Fe et en silice, légèrement soussaturée en Na, K et Ca. Au Miocène sup., le système géothermique régional, ancêtre de celui de Larderello, a été alimenté par des solutions marines, probablement même par des saumures évaportiques messiniennes. L'arrêt de l'activité métallogénique est corrélé à l'émersion du Sud de la Toscane au début du Pliocène. L'anhydrite fait de Niccioleta un cas particulier; le modèle géothermal proposé est plus général. Ses mécanismes sont applicables à de nombreuses minéralisations formées à partir de fluides chlorurés, à haute pression et température.

---

The infiltration metasomatism by chloride solutions, between 425°C-500 b and 475°C-1,000 b, has made the pyrite ore-deposit of Niccioleta. The transformations of the substrates (anhydrite-rocks, dolostones, mica schists) show the mechanisms of metasomatism and the fluid composition evolution. Changes of composition of the solvent (XCO₂, XH₂O, XH₂S, fS₂, fO₂) are very important and explain the preponderant action of fluid rocks, such as carbonated and sulfated rocks, in hydrothermal metallogenesis. The carriage of Fe is related to a low undersaturation in Na, K and Ca of a fluid with a constant chloride charge. It deposition results of reactions with Na-, K- or Ca-rich rocks; their dissolving induces the precipitation of Fe, less soluble than Na, K and Ca in chloride fluids. The effects of carbonated and sulfated rocks are double: Ca on the chloride equilibria, CO₂ or S species on the solvent. The importance of successive transformations is well shown in the case of the anhydrite: a secondary fluid, going out of a dedolomitization zone, CO₂-rich and silica undersaturated, changes the sulfate into pyrite; a primary fluid gives andradite. The original, primary, fluid is a reducing and acid chloride aqueous solution (0.9 to 1.8 m NaCl), Fe- and silica-rich, CO₂-poor, and lightly undersaturated in Na, K and Ca.During the Upper Miocene, the regional geothermal system, ancestor of the Larderello one, has been feeded by marine waters, and probably by the messinian evaporitic brines. The end of the metallogenic activity is closely correlated with the emergence of South Tuscany in the Early Pliocene. If the anhydrite-rocks makes Niccioleta to be a peculiar case, the geothermal metallogenic model proposed has a more general interest. Its mechanisms seem to be applicable to numerous mineralizations made by aqueous chloride solutions at high temperatures and pressures.

  相似文献   

To accrete or not accrete,that is the question     

Dr. Roland von Huene 《International Journal of Earth Sciences》1986,75(1):1-15

Along modern convergent margins tectonic processes span a spectrum from accretion to erosion. The process of accretion is generally recognized because it leaves a geologic record, whereas the process of erosion is generally hypothetical because it produces a geologic hiatus. Major conditions that determine the dominance of accretion or erosion at modern convergent margins are: 1) rate and direction of plate convergence, 2) sediment supply and type in the trench, and 3) topography of the subducting ocean floor. Most change in structure has been ascribed to plate motion, but both erosion and accretion are observed along the same convergence margin. Thus sediment supply and topography are probably of equivalent importance to plate motion because both erosion and accretion are observed under constant conditions of plate convergence.The dominance of accretion or erosion at a margin varies with the thickness of trench sediment. In a sediment flooded trench, the proportions of subducted and accreted sediment are commonly established by the position of a decollement along a weak horizon in the sediment section. Thus, the vertical variation of sediment strength and the distribution of horizontal stress are important factors. Once deformation begins, the original sediment strength is decreased by sediment remolding and where sediment thickens rapidly, increases in pore fluid pressure can be pronounced.In sediment-starved trenches, where the relief of the subducting ocean floor is not smoothed over, the front of the margin must respond to the topography subducted as well as that accreted. The hypothesized erosion by the drag of positive features against the underside of the upper plate (a high stress environment) may alternate with erosion due to the collapse of a margin front into voids such as graben (a low stress environment).

---

Zusammenfassung Entlang modernen konvergierenden Plattenrändern können tektonische Prozesse ein weites Spektrum von Anlagerung bis Erosion umspannen. Der Prozeß der Anlagerung wird generell erkannt, weil er eine geologische Folge aufbaut. Demgegenüber bleibt der Prozeß der Erosion im allgemeinen hypothetisch, weil er einen Hiatus hinterläßt. Die wesentlichen Bedingungen, die das Vorherrschen von Anlagerung oder Erosion bestimmen, sind: 1) Richtung und Rate der Plattenkonvergenz. 2) Sedimentlieferung und-art im Graben. 3) Topographie des subduzierenden Ozeanbodens. Die meisten Wechsel in der Struktur werden der Plattenbewegung zugeschrieben, aber sowohl Erosion als auch Anlagerung sind an demselben konvergierenden Plattenrand beobachtet worden. Daher sind wahrscheinlich die Sedimentanlieferung und die Topographie von gleichrangiger Bedeutung im Hinblick auf die Plattenbewegung, weil Erosion und Anlagerung unter konstanten Bedingungen von Plattenkonvergenz beobachtet werden.Das Vorherrschen von Anlagerung oder Erosion entlang einem Plattenrand variiert mit der Mächtigkeit der Grabensedimente. In einem sedimentbeladenen Graben werden die Verhältnisse von subduzierten und angelagerten Sediment im allgemeinen etabliert durch die Lage einer Abschiebung entlang einem schwachen Horizont innerhalb des Sedimentstapels. Daher sind die Variation der Sedimentfestigkeit in der Vertikalen sowohl als auch die Verteilung der horizontalen Spannungen bedeutende Faktoren. Sobald die Deformation beginnt, nimmt die ursprüngliche Sedimentfestigkeit ab durch die Umgestaltung des Sediments und dort, wo die Sedimentmächtigkeit rasch zunimmt, steigt der Porenwasserdruck deutlich an.In sedimentarmen Gräben, wo das Relief des subduzierten Ozeanbodens nicht ausgeglättet wird, muß die Front des Plattenrandes sowohl auf die subduzierte Topographie reagieren als auch auf die der Anlagerungsgefüge. Die hypothetische Erosion durch den Widerstand der positiven morphologischen Formen gegenüber der Unterseite der höher gelegenen Platte (ein environment hoher Spannungen) kann alternieren mit Erosion, die auf dem Kollabieren eines Plattenrandes in Hohlräume wie etwa in Gräben hinein beruht (ein environment niedriger Spannungen).

---

Résumé Le long des bords des plaques convergentes actuelles, l'action tectonique couvre une gamme de processus qui va de l'accrétion à l'erosion. Un processus d'accrétion est d'ordinaire démontré par les traces géologiques qui qu'il laisse, tandis qu'un processus d'érosion, engendrant un hiatus géologique, est geéralement hypothétique. Les principales conditions qui déterminent la prédominance de l'un ou de l'autre processus sont: 1) la cinématique (vitesse et direction) de la convergence; 2) la quantité et la nature de l'apport sédimentaire dans la fosse; 3) la topographie du fond océanique en voie de subduction. La plupart des changements de structure ont été rapportés à la cinématique des plaques. Cependant des actions d'érosion et d'accrétion sont observés le long d'une même bordure convergente; par conséquent l'apport sédimentaire et la topographie océanique jouent probablement un rôle aussi important que la cinématique des plaques.La prédominance de l'accrétion ou de l'érosion le long d'une jonction dépend de l'épaisseur des sédiments de la fosse. Dans une fosse remplie de sédiments, les proportions de sédiments subductés et accrétionnés sont communément déterminés par la position, dans la série sédimentaire, d'un horizon peu résistant le long duquel s'opère un décollement. Il en résulte que les variations verticales de compétence des sédiments et la distribution des contraintes horizontales sont des facteurs importants. Dès que la déformation commence, la résistance mécanique originelle des sédiments est abaissée par leur fluage et, là où les sédiments s'épaississent rapidement, il peut y avoir accroissement marqué de la pression des fluides intersticiels.Dans des fosses pauvres en sédiments, et lorsque le relief du fond océanique en subduction n'est pas aplani, la position du contact des plaques doit résulter autant de la topographie de la plaque descendante que de celle de la plaque supérieure. L'érosion hypothétique due à l'entraînement de formes de relief sous la plaque supérieure (situation de contraintes élevées) peut alterner avec une érosion due à l'effondrement du bord de la plaque par un mécanisme de type «>graben»< (situation de contraintes basses).

---

. , , , , . . . , : ) ; ) ; ) . , . , , , . . , . , , . , . , , . , , , . ( ) , , .: ( ).

  相似文献   

Deuterium-Isotopengeochemie des Grund- und Oberflächenwassers     

Dr. Roland Eichler 《International Journal of Earth Sciences》1966,55(1):144-159

Zusammenfassung Die Niederschlag- und Quellwässer einiger Gebiete Mitteleuropas sowie Sickerwässer aus Lysimetern und Bodenprofilen wurden vergleichend auf ihren Wasserstoffisotopen-Gehalt untersucht. Regionale Unterschiede sind vorhanden. Im Deuterium-Gehalt von Niederschlag-, Boden- und z.T. Lysimeterwasser treten regelmäßige Variationen auf. Sie fehlen im Quellwasser natürlicher Gebiete. Die Anwendbarkeit von Deuteriumuntersuchungen zur Ermittlung der Sickergeschwindigkeit und des Verdunstungsanteils wird angedeutet.

---

Rain- and spring water of several regions of Central Europe as well as water from lysimeters and soil profiles have been compared with respect to their hydrogen isotope content. Regional differences can be stated. Systematic variations in the deuterium content of rain-, soil- and in part of lysimeterwater are found to exist. They do not exist in natural spring water. The applicability of deuterium investigations to the determination of percolation velocity and evaporation is indicated.

---

Résumé L'eau de précipités et des eaux de sources de quelques régions de l'Europe Central ainsi que des eaux de lysimètres et de profils de terre sont investigées comparativement pour leur contenu d'isotopes d'hydrogène. Des différences régionales sont présentes. Il y a des variations systematiques dans le contenu de deuterium des eaux de pluie, de terre et en part de lysimètres. Elles sont absentes dans les eaux de sources naturelles. L'application des investigations de deuterium pour la détermination d'évaporation et de la vitesse d'écoulement est indiquée.

---

. .

  相似文献   

Chemical Characterisation of NIST Silicate Glass Certified Reference Material SRM 610 by ICP-MS, TIMS, LIMS, SSMS, INAA, AAS and PIXE   总被引：2，自引：0，他引：2  

Alexander B.E. Rocholl  Klaus Simon  Klaus Peter Jochum  Frank Bruhn  Roland Gehann  Utz Kramar  Werner Luecke  Michael Molzahn  Ernst Pernicka  Michael Seufert  Bernhard Spettel  Jens Stummeier 《Geostandards and Geoanalytical Research》1997,21(1):101-114

National Institute of Science and Technology (NIST) silicate glass SRM 610 is widely used as a certified reference material for various micro-analytical techniques such as SIMS or laser ablation ICP-MS. SRM 610 has been nominally doped with sixty one trace elements at the 500 μg g⁻¹ level, but certified concentration data exist for only a few of these elements. This study reports concentration data for fifty nine trace elements obtained by ICP-MS, SSMS, LIMS, TIMS, INAA, AAS, and PIXE analyses of two different SRM 610 wafers. Most elements fall within a 10% band around a median value of about 440 μg g⁻¹. The REE concentrations are shown to be constant to 3% (1 σ), thus emphasizing the value of SRM 610 as a reference material for REE analyses.
Comparison of our values with published data suggests that different SRM 610 wafers are, within errors, chemically identical for most elements. Exceptions to this general rule appear to be restricted to elements which were partly lost during the production of the glass, e.g. Ag and Br. On the basis of six independent determinations of Rb concentrations, which are systematically lower by a few percent than the reported NIST value, we argue that the certified Rb concentration may not be representative for all distributed SRM 610 wafers.  相似文献   

A technique for modeling transport/conversion processes applied to smectite-to-illite conversion in HLW buffers   总被引：3，自引：0，他引：3  

Harald Hökmark  Ola Karnland  Roland Pusch 《Engineering Geology》1997,47(4):10-378

This paper describes an application of a technique developed for modeling chemical processes in buffer materials that are controlled by a reaction rate and by the transport of one component, which is essential for the process in question to occur. The application described here is the illitization of smectite by fixation of potassium ions in cation exchange positions, and with diffusion of dissolved potassium being the transport process. The technique is verified by comparison with analytical solutions. An overview, based on small models, is given which outlines under what constellations of assumptions the time scale for conversion of the buffer is controlled by reaction rate parameters and under which conditions transport controls this time scale. Examples are given of calculations performed for deposition holes, with potassium being supplied from the surroundings to the upper parts of the highly compacted bentonite buffer. It is concluded that restrictions in nearfield transport capacity have a very significant effect on the conversion time scale. Towards the end of the heating period about 98% of the smectite is found to remain, even for reaction rates and buffer transport conditions that would have left only 10% of the smectite unconverted without nearfield transport restrictions. It is also concluded that the modeling technique can be applied to other, similar, transport/conversion processes.  相似文献   

The Caledonian deformed ordovician of the Rügen area -sediment provenance and tectonic studies     

Gerhard Katzung  Roland Walter  Uwe Giese 《Studia Geophysica et Geodaetica》1995,39(3):262-268

Summary The Ordovician of the Rügen area shows no affinities with that of the adjacent regions of the East European Platform, situated immediately to the north (i.e. Bornholm and Skåne). By contrast, the detritus in the sandstones and greywackes points to an active continental margin in the southwest, along the southern border of the suspect Tornquist Ocean (i.e. northern Peri-Gondwana). Deformation features can be assigned to Caledonian tectonic events. The more than 3 km thick pile comprises a stacked wedge complex, which was emplaced against and onto the southwestern border of Baltica.  相似文献