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111.
Mineralogy and Petrology - The concentrations of 26 trace elements have been determined by laser ablation ICP-MS in zircons from four samples of basic rocks of the Korosten... 相似文献
112.
Leonid V. Zamana 《中国地质》2010,37(3):582-586
本文通过对在外贝加尔大骨节病区水文地球化学研究结果表明,该地区天然水呈现出高浓度的磷(高达3.5mg/L),同时,锰、硅、铅等元素也呈现出高浓度的地球化学特征。分析水文地球化学数据,认为大骨节病可能与生物地球化学性质的多种因素有关系。进一步研究大骨节病的成因机制需要新的可靠的环境地球化学数据。 相似文献
113.
Achim?KopfEmail author Annette?Deyhle Vasili?Y.?Lavrushin Boris?G.?Polyak Joris?M.?Gieskes Guram?I.?Buachidze Klaus?Wallmann Anton?Eisenhauer 《International Journal of Earth Sciences》2003,92(3):407-425
The Caucasian orogenic wedge formed as a consequence of the closure of the Tethyan Ocean, and numerous fields of active mud volcanoes pepper the area adjacent to the Black and Caspian Seas. Stable isotope ratios of boron, helium, and carbon have been measured for gas, fluid and sediment samples from active mud volcanoes of Taman Peninsula and Georgia to estimate the sources and mobilization depths of the fluid phase and mud. Boron concentrations in mud volcano fluids were found to be 5–35× higher than seawater. Fluid isotope ratios vary between 11B=22 and 39, while isotope ratios of the smectite- and illite-rich extruded mud are considerably depleted in heavy 11B (11B=–8 to +7). B contents of these muds are ~8× higher than modern marine sediments. This suggests that liquefaction prior to mud volcanism was accompanied by both B enrichment and isotope fractionation, most likely at an intermediate depth mud reservoir at 2–4 km.The hydrocarbon-generating source beds to the mud volcanoes are located at 7 to >10 km depth in the folded Maikop Formation and are of proposed Oligocene–Miocene age. The most likely mechanism is re-hydration of these shales by both hydrocarbons and a geochemically mature fluid from greater depth within the orogenic wedge. Such a deep fluid source is supported by our results from gas analyses, which imply an admixture of minor amounts (less than 1%vol) of 3He (Georgia), thermogenic 13C in methane as well as "ultraheavy" 13C in CO2 (both Taman and Georgia). The overall results attest active local flow of geochemically different fluids along deep-seated faults penetrating the two study areas in the Caucasian orogenic wedge, with the waters as well as the gases coming from below the Maikop Formation. 相似文献
114.
115.
B.G. Polyak Ph. Bouysse V.I. Kononov G.Yu. Butuzova A. Criaud V.I. Dvorov M.D. Khutorskoy V.G. Matveev V.I. Paduchikh E.P. Radionova A.A. Rot I.N. Tolstikhin A.I. Voznesenskiy V.P. Zverev 《Journal of Volcanology and Geothermal Research》1992,54(1-2)
During the Soviet-French survey carried out on board of the R.V. Akademik N. Strakhov, between Guadeloupe and Montserrat island in the central Lesser Antilles, evidence of submarine hydrothermal activity was discovered on the southeastern tip of the Shoe-Rock escarpment. The latter is part of a large, 130 km long, transverse structure, the Montserrat-Marie Galante fault, which crosses the Guadeloupe archipelago. Another locus of activity, probably of subdued importance nowadays, is represented by the d'Entrecasteaux dome, a small faulted seamount, located about 25 km to the SW of the former area.The evidence for hydrothermal activity is: (a) a wide range of values of conductive heat flow (q=6–11 mW/m2) and regular vertical variation at some sites with extreme values located close to the two above-mentioned features (average regional value, q = 105 mW/m2, s.d. = 32); (b) occurrence of secondary mineralizations (todorokite, nontronite, etc.) replacing locally the primary matrix of basal upper Pliocene deposits; (c) geochemical anomalies in seawater near the sea bottom, showing enrichment in mantle-derived 3He (δ3He up to 10.2%), correlated with a sharp Zn anomaly (content up to 523 ppb).Further investigations along the submerged segments of the Montserrat-Marie Galante fault should probably lead to other discoveries of hydrothermal venting and/or mineralizations. 相似文献
116.
Michael S. Zhdanov Vjacheslav V. Spichak Leonid Yu. Zaslavsky 《Physics of the Earth and Planetary Interiors》1990,60(1-4):53-61
A method for numerical modeling of quasi-stationary electromagnetic fields in axially symmetric media is proposed. It is based on the direct finite-element method and the use of special basis functions. Assuming cylindrical coordinates r, φ, z, the three-dimensional solution is presented as a superposition of fields with the azimuthal dependence exp(inφ). For each case this results in a system of two equations of elliptical type in two scalar functions in the (r, z) plane.
The discretization leads to the conservative nine-points difference scheme. The system of linear equations is solved by means of the LU-decomposition technique, the band structure of the matrix being taken into account.
The program is tested using analytical results (DC asymptote) for a near-surface inhomogeneity. Comparison also is made with 2D results (H-polarization) for the model of a local well conducting inclusion in a three-layered Earth. 相似文献
117.
118.
High-pressure and high-temperature in situ X-ray diffraction study of iron and corundum to 68 GPa using an internally heated diamond anvil cell 总被引:1,自引:1,他引:0
Leonid S. Dubrovinsky Surendra K. Saxena Peter Lazor 《Physics and Chemistry of Minerals》1998,25(6):434-441
Using powder X-ray diffraction of heated solids to pressures reaching 68 GPa, the pressure-volume-temperature (PVT) data on
corundum Al2O3 and ɛ-Fe were determined with the following results:
*Corundum,*Iron, *Al2O3*ɛ-Fe
Isothermal bulk*258 (2)*164 (3) modulus K'300, 1 (GPa)
Pressure derivative K300, 1*4.88 (4)*5.36 (16)
Temperature derivative*–0.020 (2)*–0.043 (3) (∂K
T,1
/∂T)
P
(GPa/K)
Molar volume V300,1*25.59 (2)*6.76 (2) (cm3/mol)
Isobaric thermal expansion at 1 atm (0.101 MPa) is given by (K–1):
α
T
=2.6 (2) 10–5+1.81 (9) 10–9
T–0.67 (6)/T
2 for corundum, and α
T
=5.7 (4) 10–5+4.2 (4) 10–9
T–0.17 (7)/T
2 for iron ɛ-Fe.
Received: 1 March 1997 / Revised, accepted: 21 August 1997 相似文献
119.
Heat generation due to decay of long-lived radioactive isotopes is considered in the Earth’s crust of the Archean–Proterozoic and Paleozoic provinces of Eurasia and North America. The heat flow that forms in the mantle is calculated as the difference between the heat flow observed at the boundary of the solid Earth and radiogenic heat flow produced in the crust. The heat regime in regions with anomalously high radiogenic heat generation is discussed. The relationship between various heat flow components in the Precambrian and Phanerozoic provinces has been comparatively analyzed, and the role of erosion of the surfaceheat- generating layer has been estimated. 相似文献
120.
Olga N. Karasyova Lyudmila I. Ivanova Leonid Z. Lakshtanov Lars Lövgren Staffan Sjöberg 《Aquatic Geochemistry》1998,4(2):215-231
The acid/base properties of the hematite/water interface and surfacecomplexation with gold has been studied by potentiometric titrations in thefour component system H+ – FeOH –AuCl
4
-
– Cl-. Equilibrium measurementswere performed in NaCl media at 298.2 K. In the evaluation of equilibriummodel from experimental data the constant capacitance model was applied. Theacid/base properties were investigated in 0.1 M NaCl in the range 2.6 pH 7.4. The resulting intrinsic constants for protonation anddeprotonation of hydroxyl groups at the surface were log
1,1,0,0(int)
s
= 7.10 ± 0.06 andlog
-1,1,0,0(int)
s
= - 7.80 ±0.06. The density of proton active surface sites was 2.85nm-2 and the specific capacitance 2.5 C V-1 m-2. In the investigation of surface complexation of gold, thepotentiometric titrations were performed in the range 2.0 pH 10.2.Titration data was supplemented with analysis of Au in the aqueous phase byatomic absorbance spectrometry. The equilibrium model proposed consists ofthe following monodentate surface complexes: FeOHAuCl3(log
0,1,1,-1
s
= 1.45 ± 0.03),FeOHAuCl2OH (log
-1,1,1,-2
s
= -3.89 ± 0.02), FeOHAu(OH)3 (log
-3,1,1,-4
s
= -21.94 ± 0.05). Aslightly better fit could be obtained by assuming formation of a bidentatecomplex with the composition(FeO)2Au(OH)H2O. However, based onstructural arguments this complex was rejected. 相似文献