The distribution of gallium, germanium, cobalt, chromium, and copper in iron and stony-iron meteorites in relation to nickel content and structure

Lovering, J. F.; Nichiporuk, Walter; Chodos, A. A.; Brown, Harrison

doi:10.1016/0016-7037(57)90099-6

Cited by 190 publications

(68 citation statements)

References 6 publications

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“…Kelly and Larimer (1977) pointed out similarities in oxidation levels and the volatile element depletion factor between group IIIAB iron and ordinary chondrite. In addition, the relationship between pallasite and IIIAB iron had also been suggested by Lovering et al (1957), Buseck and Goldstein (1969) and Scott (1977b). It is unlikely that pallasite-IIIAB iron and ordinary chondrite had a common origin, because the olivines in the main-group pallasites have different oxygen isotope ratios from the sili 167 cates in ordinary chondrites (Clayton et al, 1976;Clayton and Mayeda, 1978).…”

Section: Resultsmentioning

confidence: 90%

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Experimental study of major and trace element partitioning among olivine,metallic phase and silicate melt using chondrite as starting material:Implication for V-shaped REE patterns of the pallasite meteorites.

1998

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The partition coefficients of rare earth elements (REE) and Sr between olivine and silicate melt and those of Ga, In and TI between metallic phase and silicate melt were experimentally determined under atmospheric pressure using L6 chondrite (ALH-76009) as a starting material. Temperature and oxygen fugacity were finely controlled; temperature = 1320, 1370, 1420 and 1440°C and oxygen fugacity = 0.5, 1.0, 1.5 and 2.0 log units lower than the Fe-FeO boundary on the iron-oxygen phase diagram.Olivine formed at 1320°C shows REE partition patterns with horizontal or heavy-REE-enriched features, having partition coefficients from 0.02 to 0.08. Inclination of light-REE increases with increase of tem perature of olivine formation. Finally, at the temperature of 1440°C near the liquidus of the chondrite, olivine/liquid partitioning of REE displays a V-shaped feature with partition coefficients of 0.15-0.8 for La, 0.08-0.3 for Lu and 0.05-0.09 for Dy and Er. The V-shaped REE patterns are known to be characteristic of olivine in the main group pallasites, for which our REE results imply the formation at higher tempera tures near the liquidus of olivine. Our results of major element partitioning also support the idea that such pallasites were formed at a temperature near the liquidus. Experiments of this study show that compositions of olivine formed at 1440°C are Fa8-Fa13 comparable to those of the main group pallasites, while those formed at 1320°C are Fa15-Fa18.The REE concentrations in the ferrous olivine of two pallasites, Springwater (Fa18 ,o) and Eagle Station (Fa20.0), were determined here. It was found that their chondrite-normalized REE patterns also show V shaped features, as observed for the olivine of the main group pallasites, the Brenham (Fa12 .5) and Thiel Mts. (Fa13.0) pallasites. These results suggest that the olivines of Springwater and Eagle Station were also formed at temperatures near liquidus around 1450°C. The difference in major element compositions between the main group pallasites (Brenham and Thiel Mts.) and the other pallasites (Springwater and Eagle Station) may be due to differences in major element compositions of their sources, oxygen fugacity at their formation and/or the cooling history of the pallasites. In the last case, it is reasoned that at lower temperatures (e.g., ca. 1300°C), Fe and Ni in olivine of non-main group pallasites were reequilibrated with those in the metal phases, but V-shaped REE patterns were retained because the diffusibility of REE is lower than those of Fe and Ni. The main group pallasites are considered to be free from the lower temperature reequilibrium processes.

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Section: Resultsmentioning

confidence: 90%

“…The concentration of Ga in the metal of pallasites was determined by Lovering et al (1957), Wasson and Kimberlin (1967), Wasson and Sedwick (1969) and Scott (1977a). The range was from 13 to 27 ppm with the exception of an anomalous Eagle Station trio.…”

Section: Resultsmentioning

confidence: 99%

Experimental study of major and trace element partitioning among olivine,metallic phase and silicate melt using chondrite as starting material:Implication for V-shaped REE patterns of the pallasite meteorites.

1998

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“…When a metal deposits (back reaction in equilibrium reaction (2)) and is incorporated into the octahedrite, hexahedrite, or ataxite structure in accordance with crystallographic principles, the mobilized metal chlorides from which the metals deposit will have had very different spatial and temporal histories (mobilization via equilibrium reaction (1) or (2), differing mobilization temperatures, and in some cases the effects of reaction dominance change). This model of iron meteorite formation could therefore be seen as providing an explanation for the numerous, in some cases confusing and contradictory, correlation diagrams presented by numerous authors (Buchwald, 1975;Lovering et al, 1957;Mason, 1979;Scott, 1972;Wedepohl, 1970Wedepohl, /1972). …”

Section: Argument 7: Cobalt Nickel and Their Relationships To Germanmentioning

confidence: 65%

“…The role played by the trace elements germanium and gallium in the classification of irons has received considerable attention (Benedix et al, 2014;Buchwald, 1975;Goldstein et al, 2009;Lovering, Nichiporuk, Chodos, & Brown, 1957;Mason, 1979;Scott, 1972;Wasson, 1974). As Figure 4 shows, there is excellent correlation between the concentrations of germanium and gallium in octahedrites, hexahedrites, and ataxites (r = 0.91).…”

Section: Argument 5 Alteration Of Meteorites By Cftmentioning

confidence: 99%

Formation of nickel–iron meteorites by chemical fluid transport

Schrön¹

2017

ScienceOpen Research

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The deposition of solid material from the gas phase via chemical vapor transport (CVT) is a well-known process of industrial and geochemical relevance. There is strong evidence that this type of thermodynamically driven chemical transport reaction plays a significant role in certain natural processes. This article presents detailed evidence that CVT is a highly plausible mechanism for the formation of iron meteorites. In this study, naturally occurring CVT is referred to as "chemical fluid transport" (CFT) and the end products deposited from the gas phase as "fluidites."Treating iron meteorites as cosmic fluidites enables simple solutions to be found to the problem of how they formed and to numerous related and in some cases unresolved questions. This study is based on a thermodynamic trend analysis of solid-gas equilibrium reactions involving chlorine-and fluorinecontaining compounds of 42 chemical elements that include a systematic examination of reaction dominance switching behavior. In order to assess the transport behavior of the individual elements, the reaction-conditioned pressures p MeX were calculated from the equilibrium constants. For a selected group of minerals, the relative propensity of these minerals to deposit from the gas phase was then derived from the equilibrium constants. The study shows that octahedrites, hexahedrites and ataxites formed as a result of the transport of metal chlorides and fluorides (CFT) during accretion within the solar nebula. Siderophile elements are characterized by the similarities in their chemical transport properties. These chemical properties of the elements, expressed in the form of the reaction-conditioned pressure, play a key role in determining the chemical composition of iron meteorites. The mobilization process that leads to the formation of the gaseous metal halides MeX includes the reduction of oxides. The deposition of nickel-iron bodies occurs via back reaction after the transport of the gaseous halides. The back reaction leads to the thermodynamically favored deposition of schreibersite before troilite and of troilite before kamacite/taenite. The deposition temperature of octahedrites and hexahedrites lies below the temperature at which Widmanstätten patterns would be destroyed, while that of ataxites lies slightly above. Similarly, the occurrence of thermally instable cohenite in meteorites provides further support for the fluidite character of irons.The variation in the trace element concentrations in iron meteorites is explained by enrichment and depletion mechanisms in the gas phase. The striking correlation between gallium and germanium abundances in iron meteorites is the result of similarities regarding the mobilization phase and the reaction dominance switching behavior of both elements, and crystal isomorphism.These findings are supported by numerous arguments that provide evidence for the CFT model. The occurrence of the mineral lawrencite FeCl 2 in meteorites is interpreted as an indication of the effectiveness of the chemical transp...

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“…Whereas Gus'kova and Pochtarev referenced magnetic studies on meteorites which were conducted outside the Soviet Union (e.g., Lovering, et al 1957Lovering, et al , 1960Stacey, etal., 1958Stacey, etal., , 1961 we have found no reference to the Russian work except in their own papers. * Because of the apparent lack of awareness concerning these Russian reports, we thought it fitting to write this brief summary review of their work.…”

Section: Introductionmentioning

confidence: 99%