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271.
The Sr and Pb isotopes from the 31.6 ± 0.3 Ma (2σ) old Diente del Bufa alkali syenite, northeastern Mexico, and marbles of
its contact aureole were used to trace the sources and the mobility of these metals during hydrothermal activity. Chert layers
form aquifers within the marbles. The marbles represent aquitards. During fluid-wallrock reaction, the chert layers developed
wollastonite rims. Early wollastonite rims have Sr and Pb isotopic compositions similar to those of their immediate host marbles,
which indicates that the isotopic composition of Sr and Pb is initially buffered by the marble. Later wollastonite and other
replacement minerals rimming the aquifer have Sr and Pb isotopic compositions that carry with time increasingly larger contributions
from the high-salinity magmatic brine. The Sr and Pb contributions from the alkali syenite can be traced isotopically for
more than 90 m away from the contact of the intrusion. In contrast, Sr and Pb originating from the alkali syenite are traceable
within the marbles only for 3 to 5 cm from the aquifer-marble boundary. This distance is comparable to the spatial distribution
of isotopic alterations of C and O implying that Sr and Pb were transported into the marbles through a fluid phase. The isotopic
variation of Sr, Pb, C, and O across the aquifer-marble profiles reflects infiltration as a transport mechanism rather than
diffusion. Because Sr and Pb are minor components in both the infiltrating fluid and the rock and because their concentrations
are strongly affected by the distribution coefficients among the solid phases present, there is little correlation between
the isotopic compositions of the trace elements Sr and Pb and those of C and O, which are major components in fluid and rock.
Very thin meta-argillite rinds at the outer margin of the aquifer represent residual material after the dissolution of calcite.
They are distinctly enriched in Rb, Sr, and U. The Rb and Sr are to some extent residual from the original limestone mineralogy,
whereas U is dominantly derived from the magmatic fluid and leaked from the aquifer with the escaping immiscible CO2-rich H2O-CO2 fluid that was produced by decarbonation. The 238U/204Pb values ranging from 100 to 250 and distinctly lowered Th/U in the meta-argillite rims (1) demonstrate that U was transported
with the magmatic fluid along the aquifer and (2) imply that during unmixing of the highly saline magmatic fluid U fractionated
into the CO2-rich H2O-CO2 fluid from which it precipitated selectively in the meta-argillite band across the aquifer. Radioautographs demonstrate that
the upper meta-argillite rim has 20 to 40 times more U than the lower rim, which implies that 20 to 40 times more CO2-rich H2O-CO2 fluid has left through the upper aquifer contact.
Received: 30 September 1997 / Accepted: 15 December 1997 相似文献
272.
The system Ca2Al3Si3O11(O/OH)-Ca2Al2FeSi3O11(O/OH), with emphasis on the Al-rich portion, was investigated by synthesis experiments at 0.5 and 2.0 GPa, 500-800 °C, using the technique of producing overgrowths on natural seed crystals. Electron microprobe analyses of overgrowths up to >100 µm wide have located the phase transition from clinozoisite to zoisite as a function of P-T-Xps and a miscibility gap in the clinozoisite solid solution. The experiments confirm a narrow, steep zoisite-clinozoisite two-phase loop in T-Xps section. Maximum and minimum iron contents in coexisting zoisite and clinozoisite are given by Xpszo (max) = 1.9*10 - 4 T+ 3.1*10 - 2 P - 5.36*10 - 2{\rm X}_{{\rm ps}}^{{\rm zo}} {\rm (max) = 1}{\rm .9*10}^{ - 4} T{\rm + 3}{\rm .1*10}^{ - 2} P - {\rm 5}{\rm .36*10}^{ - 2} and Xpsczo (min) = (4.6 * 10 - 4 - 4 * 10 - 5 P)T + 3.82 * 10 - 2 P - 8.76 * 10 - 2{\rm X}_{{\rm ps}}^{{\rm czo}} {\rm (min)} = {\rm (4}{\rm .6} * {\rm 10}^{ - {\rm 4}} - 4 * {\rm 10}^{ - {\rm 5}} P{\rm )}T + {\rm 3}{\rm .82} * {\rm 10}^{ - {\rm 2}} P - {\rm 8}{\rm .76} * {\rm 10}^{ - {\rm 2}} (P in GPa, T in °C). The iron-free end member reaction clinozoisite = zoisite has equilibrium temperatures of 185ᇆ °C at 0.5 GPa and 0ᇆ °C at 2.0 GPa, with (Hr0=2.8ǃ.3 kJ/mol and (Sr0=4.5ǃ.4 J/mol2K. At 0.5 GPa, two clinozoisite modifications exist, which have compositions of clinozoisite I ~0.15 to 0.25 Xps and clinozoisite II >0.55 Xps. The upper thermal stability of clinozoisite I at 0.5 GPa lies slightly above 600 °C, whereas Fe-rich clinozoisite II is stable at 650 °C. The schematic phase relations between epidote minerals, grossular-andradite solid solutions and other phases in the system CaO-Al2O3-Fe2O3-SiO2-H2O are shown. 相似文献
273.
Kirill Shmulovich Wilhelm Heinrich Peter Möller Peter Dulski 《Contributions to Mineralogy and Petrology》2002,144(3):257-273
Fractionation of selected REE between brine and vapour was experimentally determined using a large-volume rocking Ti-autoclave that allowed quasi-isobaric sampling of liquid-vapour pairs. Samples were extracted along the 350, 400 and 450 °C-isotherms of the H2O-NaCl system, and along the 400 °C isotherm of the CaCl2 system. Total salt concentrations were either 6.6 and 10 wt% NaCl or CaCl2, respectively, and total REE concentrations were about 2 ppm of each REE. Starting pH at room temperature was 1.8, added as HCl. In another series of experiments, REEs were added in amounts of 312 ppm. Here, the starting pH at room temperature was 0.5, added as HNO3:HCl=1:2. Liquid-vapour pairs (L-V) were analysed for REE by ICP-MS methods. L-V-partitioning of REE along a particular isotherm follows broadly the partitioning of the main salt components, NaCl or CaCl2. DREE=REEV/REEL decrease rapidly from the critical point with decreasing pressure (equivalent to increasing salinity of the liquid) as the solvus opens. This is independent of the total amount of the added REE. Log DREE values show approximately linear correlations with decreasing pressure from the critical point to salt-saturated conditions where the L-V curve meets the liquid + vapour + solid boundary. At given P and T, we found a systematic variation of DREE along the La-Lu suite. HREE are enriched in the vapour phase relative to LREE. Fractionation coefficients KD=(HREEV/HREEL)/(LREEV/LREEL) increase linearly with (P=Pcrit-P along a particular isotherm. At the 450 °C isotherm, KD (Lu/La) at the critical point (425 bar and 10 wt% NaCl) is 1; about 2.5 at 350 bar (33 wt% NaCl in the liquid); and about 5 if extrapolated to salt-saturation (250 bar and 52 wt% NaCl in the liquid). The REE fractionation behaviour is similar along the CaCl2-H2O solvus boundaries. Existing equations of state and thermodynamic databases of REE species cannot predict this behaviour at L-V-equilibrium conditions. That HREE are preferentially fractionated over LREE into the vapour phase has important petrogenetic consequences. In boiling hydrothermal systems, brines will be depleted in HREE relative to LREE. Isobaric cooling is ineffective for fractionation because the solvus closes and the system eventually shifts into the one-phase field. Fractionation is most effective in systems undergoing isothermal or adiabatic decompression. In an open system, where vapour may escape through cavities, fractionation is probably controlled by a Rayleigh fractionation process, resulting in larger overall fractionation effects. Similar fractionations probably occur during magma degassing at very shallow intrusion levels. 相似文献
274.
Dr. Vesna Marchig Dr. Heinrich Gundlach Dr. Christian Schnier 《International Journal of Earth Sciences》1979,68(3):1037-1054
Zusammenfassung Aus dem Manganknollen-reichen zentralpazifischen Radiolarienschlamm wurden 114 Sedimentproben in einzelne Fraktionen getrennt, und die Fraktionen einzeln chemisch analysiert.Die Fraktion <63 m ist aus autochthonen und terrigenen Anteilen zusammengesetzt, wobei der autochthone Anteil angereichert und der terrigene verarmt ist im Vergleich zu den durchschnittlichen Tiefseetonen. Im autochthonen Anteil sind die Elemente angereichert, die für das Wachstum von Manganknollen wichtig sind.Der nichtmagnetische Anteil aus der Fraktion >63 m besteht überwiegend aus Radiolarienschalen. Daneben ist (organogener) Apatit angereichert, und eine Phase, die wir für ein neugebildetes Tonmineral halten.Einige Komponenten ändern ihren Gehalt mit der Teufe, was auf eine diagenetische Mobilisierung schließen läßt. Es wurde errechnet, daß das Angebot an Manganknollenbildenden Metallen aus der diagenetischen Mobilisierung bei weitem den Bedarf an diesen Metallen für das Manganknollen-Wachstum übersteigt.
Chemical analyses were done on the various fractions made from 114 sediment samples collected from the radiolarian ooze in an area of the Central Pacific rich in manganese nodules.The fraction <63 n contains both terrigenous and autochtonous portions; the percentage of the autochtonaus portion is greater than in the average deep-sea clay, that of terrigenous is less. The concentration of elements important for the growth of manganese nodules is elevated in the autochtonous portion.The non-magnetic part of the fraction >63 m is composed mainly of radiolarian tests. In addition, there is en elevated organogenic apatite content and a phase that we believe to be a recently formed clay mineral.The concentration of some components varies with depth, which could be due to diagenetic mobilisation. It was calculated that the supply of diagenetically mobilized metals greatly exceeds that required for the growth of manganese nodules.
Résumé 114 échantillons de boue à radiolaires de l'Océan Pacifique central, riche en nodules de manganèse, ont été séparés en fractions, et chacune de celles-ci ont été analysées chimiquement.La fraction <63 m se compose de particules autochtones et terrigènes avec un enrichissement de la partie autochtone et un appauvrissement de la partie terrigène par rapport à la composition moyenne des argiles de grande profondeur. La partie autochtone est enrichie en éléments qui jouent un rÔle important dans la croissance des nodules de manganèse.La partie non magnétique de la fraction >63 m est composée pour sa plus grande partie de tests de radiolaires. On observe également un enrichissement d'apatite (organogène) et une phase que nous considérons comme une argile de néoformation.La teneur en certains éléments varie avec la profondeur, ce qui indique une mobilisation diagénétique. Nous avons pu calculer que le disponible en métaux entrant dans la formation des nodules de manganèse par suite de la mobilisation diagénétique dépasse de loin la quantité nécessaire á la croissance des nodules.
114 . <63 m , , . , . <64 . . . , . , . , , , .相似文献
275.
Heinrich Schubert Claus Bischofberger 《International Journal of Mineral Processing》1978,5(2):131-142
Flotation is realized under highly turbulent flow conditions, so that turbulence may be process-determining, too. Because the principles of turbulent multi-phase flow have still not been fully worked out, one needs integral quantities to characterize the state of turbulence indirectly.To show the hydrodynamic conditions diagrams are introduced in which the power intensity is a function of air flow number cL; impeller rotational speed n and specific air rate qL are additional parameters. Diagrams of this kind are also useful for the characterization of the optimum operation conditions. For the flotation of different particle sizes the realization of closely defined power inputs is an important condition to obtain an optimum recovery. 相似文献
276.
Zusammenfassung Die Exploration nach Kohlenwasserstoffen in Nordspanien wird am Beispiel der Antiklinalstruktur Gastiain geschildert. Aufgrund geologischer Feldaufnahmen und seismischer Untersuchungen wurden 4 Tiefbohrungen niedergebracht, die jedoch keine wirtschaftlich verwertbaren Mengen von Kohlenwasserstoffen antrafen.Die Strukturgeschichte des Raumes Gastiain und die Gründe für das negative Ergebnis der Exploration werden diskutiert.
Herrn Professor Dr.Roland Brinkmann zum 70. Geburtstag gewidmet. 相似文献
The anticlinal structure of Gastiain is shown as an example of the exploration for hydrocarbons in Northern Spain. After geological surveys and seismic measurements, four wells were drilled, however with negative or at least not economic results.The structural history of the Gastiain region and the reasons for the negative result of the exploration are discussed.
Résumé L'exploration d'hydrocarbure dans le Nord de l'Espagne est décrite par l'exemple de l'anticline de Gastiain. A l'aide de recherches géologiques et sismiques, quatre forages ont été forés, cependant sans trouver des quantités économiquement utilisables d'hydrocarbure.L'histoire de la structure de la région Gastiain et les raisons pour le résultat négatif de l'exploration sont discutées.
Gastiain . 4 , . — .
Herrn Professor Dr.Roland Brinkmann zum 70. Geburtstag gewidmet. 相似文献
277.
278.
Heinrich Wolff 《Aquatic Sciences - Research Across Boundaries》1966,28(1):46-56
Ohne Zusammenfassung 相似文献
279.
280.
Prof. Dr. Heinrich M. Köster 《International Journal of Earth Sciences》1974,63(2):655-689
The plagioclase of the kaolinised granite of Tirschenreuth is decomposed quantitatively and the biotite almost quantitatively, on the contrary potassium feldspar and mucovite of the parent rock remained unaffected by kaolinisation. The quantity of produced kaolinite is equivalent to the quantity of decomposed plagioclase and biotite. The rare elements Pb, Cu, Cr, Ni, P, and Ti from the kaolinised minerals are adsorbed quantitatively by the kaolin. All other elements are diminished, no element has been added to the kaolin from other sources than from parent rock material. The selective decomposition of plagioclase and biotite in the kaolin-feldspar deposit of Tirschenreuth and the association of rare elements in the kaolin are explainable by weathering processes only. Kaolins from Hirschau-Sehnaittenbach are characterised by extremely high concentrations of the rare elements Ba, Sr, Pb, Cu, and P. The association of rare elements of the kaolin has been originated from the decomposed potassium feldspar of the kaolinised arcoses. The rare elements Pb, Cu, Cr, and P are adsorbed quantitatively by the kaolin. The other elements are diminished, Ba and Sr inclusive and in spite of their high absolute concentrations. The composition of the arcoses of Hirschau-Schnaittenbach prior to kaolinisation is calculated to 56% of quartz and 44% of potassium feldspar by means of the quantities of the elements Pb and Cu analysed in the feldspar and in the kaolin. The kaolin of Hirschau-Schnaittenbach has originated by weathering of the potassium feldspar of the Triassic arcoses. The kaolinisation is of Triassic age because kaolins of the Hirschau-Schnaittenbach type were redeposited near Ehenfeld in the Cenomanian. Kaolin deposits of hydrothermal origin are characterised by a zonal structure and are associated by ores. They are different in geological behaviour and mineral association from kaolin deposits which originated by weathering of feldspathic rocks like the deposits of Tirschenreuth and Hirschau-Schnaittenbach (Upper Palatinate, Bavaria). 相似文献