Experimental partial melting of the St. Severin (LL) and Lost City (H) chondrites

Jurewicz, A. J. G.; Mittlefehldt, David W.; Jones, J. H.

doi:10.1016/0016-7037(94)00328-j

Cited by 85 publications

(94 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With increasing run time (3-21 days), Feldstein et al (2001) found silicate melts with lower SiO 2 and higher Al 2 O 3 and CaO. While it is difficult to directly compare our results, this finding suggests that longer run times in our experiments might have produced melt compositions more comparable to those of Jurewicz et al (1995), although we chose shorter run times to minimize sulfur volatilization.…”

Section: Comparison To Other Partial Melting Experimentscontrasting

confidence: 38%

“…The most common type of experiment attempts to reproduce equilibrium melting over a limited range of temperature and oxygen fugacity, primarily to understand melt genesis from a chondritic source. Jurewicz et al (1991Jurewicz et al ( , 1995 reported such experiments with melting of the Allende CV3 carbonaceous chondrite and the St. Severin (LL) and Lost City (H) ordinary chondrites. Allende differs markedly in composition from the Kernouvé material we utilized, but Jurewicz et al (1991) tried the innovative approach of varying fO 2 over 4 log units to examine the influence of oxygen fugacity on melt composition.…”

Section: Comparison To Other Partial Melting Experimentsmentioning

confidence: 99%

“…Coupled with the FeO-rich nature of their starting composition, direct comparison of our experimental results is unwarranted. A more direct comparison can be made to the ordinary chondrite melting experiments of Jurewicz et al (1995), conducted at 1150-1350 °C and fO 2 of IW-1. These authors did not observe significant changes in Fe/Mg ratio of residual olivine or pyroxene with increasing temperature.…”

Section: Comparison To Other Partial Melting Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Partial melting of H6 ordinary chondrite Kernouvé: Constraints on the effects of reducing conditions on oxidized compositions

Ford

Benedix

McCoy

et al. 2008

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Abstract-Partial melting experiments at temperatures of 950-1300 °C were conducted on the H6 chondrite Kernouvé under reducing conditions using CO-CO 2 gas mixing and graphite-buffered sealed silica tubes to examine the effect of reducing conditions during melting of starting materials that are more oxidized relative to the oxygen fugacity conditions of the experiments. The experiments produced a range of mineralogical and compositional changes. Olivine exhibits significant reduction to compositions of Fa 2-5 at temperatures of 1300 °C. In contrast, orthopyroxene exhibits only slight reduction until the highest temperatures. Chromite is sometimes consumed by intruding sulfides, and displays increasingly magnesian compositions ranging as low as Fe/Fe + Mg of 0.1 at a constant Cr/Cr + Al ratio. The compositional changes with increasing temperature reflect a complex set of reactions, including oxidation-reduction. One application of these experiments address whether primitive achondrites could have formed from ordinary chondrite-like precursors by partial melting under reducing conditions. While changes observed in olivine and troilite compositions might support such an idea, differences in oxygen isotopic composition, Cr/Cr + Al in chromite, orthopyroxene compositions, and thermodynamic evidence against reduction during melting of primitive achondrites (Benedix et al. 2005) firmly refute such an idea.

show abstract

Section: Comparison To Other Partial Melting Experimentscontrasting

confidence: 38%

Section: Comparison To Other Partial Melting Experimentsmentioning

confidence: 99%

Section: Comparison To Other Partial Melting Experimentsmentioning

confidence: 99%

See 1 more Smart Citation

Partial melting of H6 ordinary chondrite Kernouvé: Constraints on the effects of reducing conditions on oxidized compositions

Ford

Benedix

McCoy

et al. 2008

Meteorit & Planetary Scien

View full text Add to dashboard Cite

show abstract

“…The temperature criterion must be at least the Fe-FeS eutectic, ∼990 °C (Usselman 1975-if production of metallic melt is assumed to satisfy the "melting" aspect of smelting); or arguably the chondritic silicate solidus, ∼1150 °C (Jurewicz et al 1995). The maximum smelting P is ∼20-80 bars, depending upon the mafic-silicate mg; lower mg implies a higher P to forestall smelting (Warren and Kallemeyn 1992).…”

Section: Implications Of Inferred Catastrophic Breakup Vis-à-vis Smelmentioning

confidence: 99%

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

Warren

Huber

2006

Meteoritics &Amp; Planetary Science

View full text Add to dashboard Cite

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.

show abstract

“…A low-degree of partial melting is best able to explain the Ca-P-Cl-rich composition of Sombrerete inclusions. These elements are concentrated in clinopyroxene and phosphate in a chondritic precursor, which are among the first phases to melt (Feldstein et al 2001;Jurewicz et al 1995), so partial melting would place much of these elements into the melt fraction. The P/Ca ratio of the melt would be greater than chondritic if a greater proportion of Ca was retained in the source (e.g., in plagioclase), consistent with Sombrerete inclusions, which have a P/Ca ratio ~4 times that of a CR chondrite.…”

Section: Partial Melting Modelsmentioning

confidence: 99%

Petrology of silicate inclusions in the Sombrerete ungrouped iron meteorite: Implications for the origins of IIE‐type silicate‐bearing irons

Ruzicka

Hutson

Floss

2006

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Abstract-The petrography and mineral and bulk chemistries of silicate inclusions in Sombrerete, an ungrouped iron that is one of the most phosphate-rich meteorites known, was studied using optical, scanning electron microscopy (SEM), electron microprobe analysis (EMPA), and secondary ion mass spectrometry (SIMS) techniques. Inclusions contain variable proportions of alkalic siliceous glass (~69 vol% of inclusions on average), aluminous orthopyroxene (~9%, Wo 1−4 Fs 25-35 , up to ~3 wt% Al), plagioclase (~8%, mainly An 70-92 ), Cl-apatite (~7%), chromite (~4%), yagiite (~1%), phosphaterich segregations (~1%), ilmenite, and merrillite. Ytterbium and Sm anomalies are sometimes present in various phases (positive anomalies for phosphates, negative for glass and orthopyroxene), which possibly reflect phosphate-melt-gas partitioning under transient, reducing conditions at high temperatures. Phosphate-rich segregations and different alkalic glasses (K-rich and Na-rich) formed by two types of liquid immiscibility. Yagiite, a K-Mg silicate previously found in the Colomera (IIE) iron, appears to have formed as a late-stage crystallization product, possibly aided by Na-K liquid unmixing. Trace-element phase compositions reflect fractional crystallization of a single liquid composition that originated by low-degree (~4-8%) equilibrium partial melting of a chondritic precursor. Compositional differences between inclusions appear to have originated as a result of a "filter-press differentiation" process, in which liquidus crystals of Cl-apatite and orthopyroxene were less able than silicate melt to flow through the metallic host between inclusions. This process enabled a phosphoran basaltic andesite precursor liquid to differentiate within the metallic host, yielding a dacite composition for some inclusions. Solidification was relatively rapid, but not so fast as to prevent flow and immiscibility phenomena. Sombrerete originated near a cooling surface in the parent body during rapid, probably impact-induced, mixing of metallic and silicate liquids. We suggest that Sombrerete formed when a planetesimal undergoing endogenic differentiation was collisionally disrupted, possibly in a breakup and reassembly event. Simultaneous endogenic heating and impact processes may have widely affected silicate-bearing irons and other solar system matter.

show abstract

Experimental partial melting of the St. Severin (LL) and Lost City (H) chondrites

Cited by 85 publications

References 18 publications

Partial melting of H6 ordinary chondrite Kernouvé: Constraints on the effects of reducing conditions on oxidized compositions

Partial melting of H6 ordinary chondrite Kernouvé: Constraints on the effects of reducing conditions on oxidized compositions

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

Petrology of silicate inclusions in the Sombrerete ungrouped iron meteorite: Implications for the origins of IIE‐type silicate‐bearing irons

Contact Info

Product

Resources

About