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Browsing Геология России by Title
Now showing items 7563-7582 of 39126
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(1999)Iron is an important constituent of kornerupine, (,Mg,Fe)(Al,Mg,Fe) 9 (Si,Al,B) 5 O 21 (OH,F). We obtained Mössbauer spectra at 300 K on twelve samples with Fe 0.30–1.30 atoms per formula unit (apfu) and Fe 3 /Fe 0–0.31; ...
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(1992)Banded iron formations (BIF) are prominent in sediments older than 2 Ga. However, little is known about the absolute abundance of BIF in Archean and Early Proterozoic sediments, and the source of the Fe is still somewhat ...
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(2003)The Fe isotope composition of Proterozoic to modern clastic sedimentary rocks and aerosols defines a range in 56Fe values that is only slightly more variable than the range of Fe isotope compositions measured in terrestrial ...
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(2004)The iron isotope compositions of Shergotty–Nakhla–Chassigny (SNC) meteorites thought to come from Mars, eucrites and diogenites assumed to sample asteroid 4 Vesta, and rocks from the Moon and Earth have been measured using ...
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(2004)Photoautotrophic bacteria that oxidize ferrous iron (Fe[II]) under anaerobic conditions are thought to be ancient in origin, and the ferric (hydr)oxide mineral products of their metabolism are likely to be preserved in ...
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(2004)In experiments investigating the causes of Fe isotope fractionation, the d56/54Fe value of Fe(II) remaining in solution (Fe(II)(aq)) after reduction of Fe(III) (goethite) by Shewanella putrefaciens is ;21.2‰ relative to ...
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IRON ISOTOPE FRACTIONATION DURING MICROBIALLY STIMULATED FE(II) OXIDATION AND FE(III) PRECIPITATION (2006)Interpretation of the origins of iron-bearing minerals preserved in modern and ancient rocks based on measured iron isotope ratios depends on our ability to distinguish between biological and non-biological iron isotope ...
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(2003)The purpose of this work is to study the mobility and budget of Fe isotopes in the oceanic crust and in particular during low-temperature interaction of seawater with oceanic basalt. We carried out this investigation using ...
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(2004)The effect of continental weathering on the iron isotope compositions of natural materials is investigated. Unweathered igneous rocks, pelagic clay, and dust fall within the range δ56Fe=0±0.3‰. Rivers with large suspended ...
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(2002)The local structure of iron in three tektites has been studied by means of Fe K-edge extended X-ray absorption fine structure (EXAFS) and high-resolution X-ray absorption near-edge structure (XANES) spectroscopy in order ...
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(2004)Iron-rich clay minerals are abundant in the natural environment and are an important source of iron for microbial metabolism. The objective of this study was to understand the mechanism(s) of enhanced reduction of Fe(III) ...
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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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(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 ...
Now showing items 7563-7582 of 39126