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Now showing items 8902-8921 of 42285
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(1989)The results of our detailed investigation of inclusions in moissanite from the Sytykan kimberlite pipe are given. Comparison of available information on inclusions in moissanite from different igneous rocks shows that they ...
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(1997)Iron speciation was determined in hemiplegic sediments from a high productivity area to investigate systematically the early diagenetic reactivity of Fe. A combination of various leaching agents (1 M HCl, dithionite buffered ...
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(2004)The stable isotope geochemistry of Fe has attracted intense interest in the past five years. This interest was originally motivated by the possible use of Fe isotopes in biosignature applications, particularly in sediments ...
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(2001)In the presence of sulfate-reducing bacteria (Desulfovibrio desulfuricans) hematite (α-Fe2O3) dissolution is affected potentially by a combination of enzymatic (hydrogenase) reduction and hydrogen sulfide oxidation. As a ...
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(2006)Various iron-bearing primary phases and rocks have been weathered experimentally to simulate possible present and past weathering processes occurring on Mars. We used magnetite, monoclinic and hexagonal pyrrhotites, and ...
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(2002)The determination of FeO of geologic materials by modern instrumental methods (such as atomic absorption spectroscopy (AAS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray fluorescence (XRF), etc.) ...
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(2005)Phosphorus is one of the nutrients most commonly limiting net primary production in soils of humid tropical forests, mainly because insoluble Al and Fe phosphates and strong sorption to Fe(III) (hydr)oxides remove P from ...
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(1999)The solubility of natural and synthetic hematite (α-Fe2O3) was measured in NaOH–NaCl solutions (0.007 ≤ m(NaOH) ≤ 2.0) between 60 and 300°C at saturated water vapour pressure and under excess oxygen. Solubility constants ...
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(1988)We studied the possibility of using metamorphic diopside-rich and diopside-bearing rocks, virtually devoid of iron, titanium and alkali oxides, in various silicate technologies. Such rocks are widespread in the Precambrian ...
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(2001)Fe,Ni-sulfide grains in nine anhydrous chondritic porous (CP) interplanetary dust particles (IDPs) and one hydrated chondritic smooth (CS) IDP were examined using 200 and 400 keV transmission electron microscopy.Crystal ...
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(2006)An Inceptisol A-horizon from Hawaii was subjected to a series of reduction-oxidation cycles - 14 d cycle length over a 56 d duration - across the "soil-Fe" [Fe(OH)3.Fe2+(aq), log Ko = 15.74] equilibrium in triplicate ...
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(1999)We have applied a stepwise pyrolytic extraction technique to eleven individual lunar regolith grains to investigate the compositions of light noble gases embedded in grain surfaces by solar wind irradiation, with emphasis ...
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(2003)We investigate the potential advantages and pitfalls of using an irregular interface parametrization in 3-D wide-angle seismic traveltime tomography. Several synthetic tests are performed using an interface surface consisting ...
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(2001)Mathematical representation of the dynamics of a highly viscous, rheologically heterogeneous, incompressible medium affected by gravity is considered. The solution is defined by reducing the original system of differential ...
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(2004)A simple analysis suggests that a time interval of more than about 5000 Myr is needed for the random palaeogeographic test to be effective in assessing the geomagnetic axial dipole assumption. This time is so long as to ...
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IS AMINO ACID CHRONOLOGY APPLICABLE TO THE ESTIMATION OF THE GEOLOGICAL AGE OF SILICEOUS SEDIMENTS? (2002)There are few conventional dating methods that can be used to estimate the geological age of siliceous sediments on the order of 104-105 yr. In contrast, methods such as δ18O are available for dating carbonate-containing ...
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(2000)We tested the hypothesis that, on the scale of a decade, earthquakes deeper than 60 km are produced at an approximately constant, that is, stationary Poissonian rate. We selected earthquakes with depths greater than 60 km ...
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(2003)Macroscopic transport properties of natural porous media, such as the permeability tensor K, are the sum of uncountable microscopic events. Understanding how these microscopic events come together to yield a descriptive ...
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(2006)Recently, X-ray spectroscopy indicated that the low-spin (LS) electronic configuration of Fe2+ and Fe3+ ions substituting in silicate perovskite of various compositions, and also in magnesiowüstite is stable at room ...
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(1995)Dense hydrous magnesium silicates (DHMS), such as phase A [Mg7Si2O8(OH)6], are potential hosts for water in the Earth's mantle. Previous work has delineated the stability field of phase A (PhA) coexisting with clinoenstatite ...
Now showing items 8902-8921 of 42285