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1.
ACOSTA-VIGIL ANTONIO; LONDON DAVID; DEWERS THOMAS A.; MORGAN GEORGE B. VI 《Journal of Petrology》2002,43(10):1885-1908
The mechanisms and kinetics of equilibration between peraluminousminerals and granitic melt were investigated experimentallyby the dissolution of corundum and andalusite into H2O-saturatedmetaluminous haplogranitic melt at 800°C and 200 MPa. Mineraland haplogranitic glass rods were juxtaposed inside platinumcapsules, and then subjected to experimental conditions fortimes ranging from 12 to 2900 h. Upon melting, the mineral –meltinterface retreats with the square root of time. The compositionof the melt at the interface changes with time, but its ASI[aluminum saturation index = molar Al2O3/(CaO + Na2O + K2O)]remains constant at 相似文献
2.
Important tendencies in development of the world mineral-resources sector at the beginning of the 21st century were an increase in production and consumption of mineral materials differentiated by types of metals and nonmetallic mineral raw materials, by countries and regions, as well as the concentration of the production of mineral raw materials in a small number of countries, and a reduction in industrial reserves of minerals in the world economy, even at the current stage of their extraction. These tendencies should be taken into account in working out a strategy for development of the Russian mineral raw-material base. 相似文献
3.
Antonio?Acosta-Vigil David?LondonEmail author George?B.?Morgan VI 《Contributions to Mineralogy and Petrology》2005,149(3):276-287
This study examines hydration–diffusion in the metaluminous haplogranite system at 200 MPa H2O and 800–300°C. At 800°C hydration is accompanied by melting and uphill diffusion of sodium from anhydrous glass toward the region of hydration and melting, whereas potassium diffuses away from the hydration front and into anhydrous glass. Silicon and aluminum are simply diluted upon hydration. There is no change in molecular Al/(Na + K) throughout the entire hydration-diffusion aureole and, therefore, (1) there is no loss of alkalis to the vapor, and (2) K migrates to replace Na in order to maintain local charge balance required by IVAl. Alkali diffusion occurs over a viscosity contrast from 104.1 Pa s in hydrous liquid to 1011.8–1013.5 Pa s in anhydrous glass. From these results, we interpret that: (1) Na is structurally or energetically favored over K as a charge-balancing cation for IVAl in hydrous granitic liquids, whereas the opposite behavior has been observed for anhydrous melts, and (2) the diffusion of alkalis through silicate melts is largely independent of viscosity. Results from 600°C are similar to those at 800°C, but hydration at 300°C involves a loss of Na and concomitant increase in molar Al/(Na + K) in the hydration zone due to hydrogen-alkali exchange between fluid and glass. Hydration behavior at 400°C is transitional between those at 300°C and 600°C, suggesting that the change in hydration mechanism occurs near the glass transition. 相似文献
4.
The results of the 35th Session of the International Geological Congress held in 2016 in Cape Town (South Africa) are discussed in this paper. The major scientific problems discussed at the most popular sections are considered. Among them are the early stages in the evolution of the Earth, studies of mineral resources worldwide, and the problems of the deep structure of the Earth, as well as modern fields of mineralogy. 相似文献
5.
The origin of the Noril’sk and Talnakh sulfide PGE-Cu-Ni deposits that are associated with Triassic basaltic traps of Siberia
is considered. It has been shown that ore elements of these deposits (with the probable exception of iron) are of a crustal
origin rather than a mantle one. They entered the basalts owing to the remobilization (recycling) of ore elements from Early
Proterozoic sediments and rocks that are presented in the basement of the Siberian Craton. The criteria for prospecting for
analogous deposits are given. 相似文献
6.
7.
Behavior and effects of phosphorus in the system Na2O−K2O−Al2O3−SiO2−P2O5−H2O at 200 MPa(H2O) 总被引：1，自引：1，他引：1
David London George B. Morgan VI Harold A. Babb Jennifer L. Loomis 《Contributions to Mineralogy and Petrology》1993,113(4):450-465
The addition of phosphorus to H2O-saturated and initially subaluminous haplogranitic (Qz–Ab–Or) compositions at 200 MPa(H2O) promotes expansion of the liquidus field of quartz, a marked decrease of the solidus temperature, increased solubility limits of H2O in melt at low phosphorus concentrations, and fractionation of melt out of the haplogranite plane (projected along an Or28 isopleth) toward a peralkaline, silica-poor but quartz-saturated minimum composition. The partition coefficient for P2O5 between aqueous vapor and melt with an ASI (aluminum saturation index, mol Al/[mol Na+K])=1 is negligible (0.06), and consequently so are the effects of phosphorus on other melt-vapor relations involving major components. Phosphorus becomes more soluble in vapor, however, as the concentration of a NaPO3 component increases via the fractionation of melt by crystallization of quartz and feldspar. The experimental results here corroborate existing concepts regarding the interaction of phosphorus with alkali aluminosilicate melt: phosphorus has an affinity for alkalis and Al, but not Si. Phosphorus is incorporated into alkali feldspars by the exchange component AlPSi-2. For subaluminous compositions (ASI=1), the distribution coefficient of phosphorus between alkali feldspar and melt, D[P]Af/m, is 0.3. This value increases to D[P]Af/m=1.0 at a melt ASI value of 1.3. The increase in D[P]Af/m with ASI is expected from the fact that excess Al promotes the AlPSi-2 exchange. With this experimental data, the P2O5 content of feldspars and whole rocks can reveal important facets of crystallization and phosphorus geochemistry in subaluminous to peraluminous granitic systems. 相似文献
8.
V. I. Starostint L. S. Kondratov D. M. Voinkov 《地学前缘》2008,15(1):51-56
抽提岩石(沉积物)中吸附气和吸收气的方法可用于预测矿藏,这是因为这些气体会逐渐聚集和保存在岩石中。来自地幔的流体会补充热解吸附流体,运移到地表的流体则产生岩石圈气田。产生于这种方式的背景气田可能会受到物理场和来自不同矿床流体的影响。矿床的物理场可能会改变背景气田的成分。 相似文献
9.
I. N. Myagkova M. I. Panasyuk Yu. I. Denisov V. V. Kalegayev A. V. Bogomolov V. O. Barinova D. A. Parunakyan L. I. Starostin 《Geomagnetism and Aeronomy》2011,51(7):897-901
The study of variations in the electron flux in the outer Earth radiation belt (ERB) and their correlations with solar processes
is one of the important problems in the experiment with the Electron-M-Peska instrument onboard the CORONAS-Photon solar observatory.
Data on relativistic and subrelativistic electron fluxes obtained by the Electron-M-Peska in 2009 have been used to study
the outer ERB dynamics at the solar minimum. Increases in outer ERB relativistic electron fluxes, observed at an height of
550 km after weak magnetic disturbances induced by high-velocity solar wind arriving to the Earth, have been analyzed. The
geomagnetic disturbances induced by the high-velocity solar wind and that resulted in electron flux variations were insignificant:
there were no considerable storms and substorms during that period; however, several polar ground-based stations observed
an increase in wave activity. An assumption has been made that the wave activity caused the variations in relativistic electron
fluxes. 相似文献
10.
Crystallization of the Little Three layered pegmatite-aplite dike, Ramona District, California 总被引：5，自引：4，他引：1
Subhorizontally layered pegmatite-aplite bodies are characterized by fine-grained, sodic to granitic aplite that is usually
juxtaposed abruptly above by much coarser-grained, commonly graphic potassic pegmatite. Although well studied, there currently
is little concensus as to how such dikes form. The Little Three dike near Ramona, California, is representative of such zoned
bodies in this and other regions, and contains discontinuous miarolitic pockets near the base of the graphic pegmatite zone.
Tourmaline, garnet, biotite, and muscovite show no changes in major- or minor-element compositions indicative of progressive
magmatic fractionation until the immediate vicinity of the main miarolitic zone, where they record abrupt and extreme enrichments
in Li, F, and Mn. There is no correlation of chemical changes in the dike with the appearance of small miarolitic vugs well
below the main miarolitic zone, nor is there any indication that the aplite, graphic pegmatite, or miarolitic pockets represent
separate magma injections. The chemistries of tourmaline, garnet, and micas, however, preclude conventional models of Rayleigh
fractionation or traditional zone refining. Textural features and modeled cooling histories indicate that the dike cooled
quickly and might have solidified partially or totally to glass before crystallization commenced. Geothermometry based on
the compositions of coexisting plagioclase and homogeneous, nonperthitic K-feldspar indicates inward crystallization of the
dike, from ∼400–435 °C at the margins to ∼350–390 °C within 20–30 cm of the pocket horizon, then a sharp decrease to 240–275 °C
in the pockets where K-feldspar is perthitic. We interpret the feldspar geothermometry (except perhaps in the miarolitic cavities)
to reflect the temperatures at crystallization fronts that advanced into the pegmatite, first from the foot wall and eventually
joined by a similar front downward from the hanging wall. Crystallization down from the hanging wall may have commenced after
∼70–80% of the foot wall aplite had crystallized. The very abrupt increases of Li, Mn, and F in tourmaline and garnet near
the miarolitic zone appear to be explained best by the process of constitutional zone refining, in which a fluxed crystallization
front sweeps an incompatible element-enriched boundary layer through a solid or semi-solid. After these two highly fluxed
boundary layers merged near the main miarolitic zone, compositional evolution could have proceeded by crystal-melt fractionation.
Received: 24 March 1998 / Accepted: 10 March 1999 相似文献