Siderophile geochemistry of ureilites: A record of early stages of planetesimal core formation

Warren, P. H.; Ulff-Møller, Finn; Huber, Heinz; Kallemeyn, G. W.

doi:10.1016/j.gca.2005.12.026

Cited by 80 publications

(102 citation statements)

References 75 publications

(191 reference statements)

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“…Sulfur itself shows no correlation with olivine-core mg. The chalcophile elements Zn, Ag, and In show essentially no correlation with olivinecore mg, and Cd shows only a marginally significant (r = 0.48 for 18 data pairs) (Warren et al 2006) anticorrelation. On balance, the available data seem permissive of considerable loss of S-rich metallic melt; and perhaps of the high-mg ureilites having lost generally more than low-mg ureilites, but not by large and systematic factors.…”

Section: Mass Balance For Fe Metal and Siderophile Elementsmentioning

confidence: 78%

“…Olivine-core mg versus modal py for ureilites (literature data; mostly reviewed by Mittlefehldt et al 1998). In the case of Meteorite Hills (MET) 01085, which lacks olivine yet appears to be a "real" ureilite (Warren et al 2006), pigeonite's mg is plotted in lieu of olivine's. Lewis Cliff (LEW) 88774 has been proposed to be a cumulate (Goodrich and Keller 2000; but see Warren et al 2006).…”

Section: Mass and Volume Balance For Co Gasmentioning

confidence: 99%

“…In the case of Meteorite Hills (MET) 01085, which lacks olivine yet appears to be a "real" ureilite (Warren et al 2006), pigeonite's mg is plotted in lieu of olivine's. Lewis Cliff (LEW) 88774 has been proposed to be a cumulate (Goodrich and Keller 2000; but see Warren et al 2006). Data for equilibrated ordinary and enstatite chondrites show a similar correlation.…”

Section: Mass and Volume Balance For Co Gasmentioning

confidence: 99%

“…If the Fe metal was removed mainly as S-rich metallic melt, the depletions should be strongest for chalcophile elements, i.e., S itself and elements with high distribution coefficient for Srich metallic liquid over FeNi solid metal, D ml/sm (Chabot and Jones 2003). Warren et al (2006) reviewed the data for S and chalcophile elements in ureilites. Sulfur itself shows no correlation with olivine-core mg.…”

Section: Mass Balance For Fe Metal and Siderophile Elementsmentioning

confidence: 99%

“…Again, CO is the only gas involved. Equation 2 might account for the extremely Sirich glasses, commonly 75-85 wt% SiO 2 , that are observed in interstitial areas of Yamato (Y-) 74123 and Y-79081 (Ogata et al 1991) as well as Northwest Africa (NWA) 766 (Warren et al 2006). Yet another variant of the smelting reaction assumes that a melt is involved in the reactants.…”

Section: Introductionmentioning

confidence: 99%

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Ureilite petrogenesis: A limited role for smelting during anatexis and catastrophic disruption

Warren

Huber

2006

Meteoritics &Amp; Planetary Science

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Abstract-A popular model for ureilites assumes that during anatexis in an asteroidal mantle, pressure-buffered equilibrium smelting (partial reduction coincident with partial melting) engendered their conspicuous mafic-silicate-core mg diversity (75-96 mol%). Several mass-balance problems arise from this hypothesis. Smelting inevitably consumes a large proportion of any plausible initial carbon while generating significant proportions of Fe metal and copious proportions of CO gas. The most serious problem concerns the yield of CO gas. If equilibrium smelting produced the ureilites' entire 21 mol% range in olivine-core mg, the proportion of gas within the asteroidal mantle (assuming plausibly low pressure <∼80 bar) should have reached ≥85 vol%. Based on the remarkably stepwise cooling history inferred from ureilite texture and mineralogy, a runaway, CO-leaky process that can loosely be termed smelting appears to have occurred, probably triggered by a major impact. The runaway scenario appears likely because, by Le Châtelier's principle, CO leakage would tend to accelerate the smelting process. Also, the copious volumes of gas produced by smelting would have led to explosive, mass-leaky eruptions into the vacuum surrounding the asteroid. Loss of mass would mean diminution of interior pressure, which would induce further smelting, leading to further loss of mass (basalt), and so on. Such a disruptive runaway process may have engendered the ureilites' distinctive reduced olivine rims. But the only smelting, according to this scenario, was a short-lived disequilibrium process that reduced only the olivine rims, not the cores; and the ureilites were cooling, not melting, during the abortive "smelting" episode.

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Section: Mass Balance For Fe Metal and Siderophile Elementsmentioning

confidence: 78%

Section: Mass and Volume Balance For Co Gasmentioning

confidence: 99%