Thermal metamorphism of primitive meteorites—XL The enstatite meteorites: origin and evolution of a parent body

Biswas, S.; Walsh, T. M.; Bart, G.; Lipschutz, M. E.

doi:10.1016/0016-7037(80)90207-0

Cited by 60 publications

(30 citation statements)

References 37 publications

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“…Whether or not the Pesyanoe regolith during its early history had higher Te abundances is not clear. The observed Te abundance in enstatite achondrites is only ~1% of Te in the enstatite chondrites, while the Se/Te ratio is the same (Biswas et al 1980). Biswas et al interpret the preservation of the Se/Te ratio as evidence for transfers of sulfide from enstatite chondritic material since this ratio would be expected to change significantly during postulated volatilization processes, which are pictured to have been operative during the formation of the parent body.…”

Section: Xe Anomaliesmentioning

confidence: 98%

Solar wind and other gases in the regoliths of the Pesyanoe parent object and the moon

Mathew

Marti

2003

Meteorit & Planetary Scien

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We report new data from Pesyanoe-90,1 (dark lithology) on the isotopic signature of solar wind (SW) Xe as recorded in this enstatite achondrite which represents a soil-breccia of an asteroidal regolith. The low temperature (≤800°C) steps define the Pesyanoe-S xenon component, which is isotopically consistent with SW Xe reported for the lunar regolith. This implies that the SW Xe isotopic signature was the same at two distinct solar system locations and, importantly, also at different times of solar irradiation. Further, we compare the calculated average solar wind "SW-Xe" signature to Chass-S Xe, the indigenous Xe observed in SNC (Mars) meteorites. Again, a close agreement between these compositions is observed, which implies that a mass-dependent differential fractionation of Xe between SW-Xe and Chass-S Xe is <1.5‰ per amu. We also observe fractionated (Pesyanoe-F) Xe and Ar components in higher temperature steps and we document a fission component due to extinct 244 Pu. Interestingly, the Pesyanoe-F Xe component is revealed only at the highest temperatures (>1200°C). The Pesyanoe-F gas reveals Xe isotopic signatures that are consistent with lunar solar energetic particles (SEP) data and may indicate a distinct solar energetic particle radiation as was inferred for the moon. However, we cannot rule out fractionation processes due to parent body processes. We note that ratios 36 Ar/ 38 Ar ≤5 are also consistent with SEP data. Calculated abundances of the fission component correlate well with radiogenic 40 Ar concentrations, revealing rather constant 244 Pu/K ratios in Pesyanoe, and separates thereof, and indicate that both components were retained. We identify a nitrogen component (δ 15 N = 44‰) of non-solar origin with an isotopic signature distinct from indigenous N (δ 15 N = −33‰). While large excesses at 128 Xe and 129 Xe are observed in the lunar regolith samples, these excesses in Pesyanoe are small. On the other hand, significant 126 Xe isotopic excesses, comparable to relative excesses observed in lunar soils and breccias, are prominent in the intermediate temperature steps of Pesyanoe-90,1.

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Section: Xe Anomaliesmentioning

confidence: 98%

Solar wind and other gases in the regoliths of the Pesyanoe parent object and the moon

Mathew

Marti

2003

Meteorit & Planetary Scien

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“…They will be discussed here even though they show substantial differences from typical aubrites. Petrologic and chemical information on aubrites was taken from Biswas et al (1980), Easton (1985), Floss and Crozaz (1993), Floss et al (1990), Keil et al (1989), Lodders et al (1993), McCoy (1998), Okada and Keil (1982), Okada et al (1988), Cohen (1967), Strait (1983), Watters and Prinz (1979), Wheelock et al (1994), and Wolf et al (1983).…”

Section: Aubritesmentioning

confidence: 99%

Achondrites

Mittlefehldt

2014

Treatise on Geochemistry

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“…Zinc abundances decrease in the sequence (average concentrations in parenthesis): EH chondrites ($290 ppm; Lodders and Fegley, 1998), Shallowater ($32 ppm; Biswas et al, 1980), EL chondrites (19 ppm; Lodders and Fegley, 1998), aubrites main group (0.5-2 ppm; Wolf et al, 1983;Lodders et al, 1993). In addition, Zn abundances show also some variations within each group with a trend of decreasing concentrations with stronger degrees of metamorphism: for example the average Zn concentration of un-metamorphosed EL3 chondrites (213 ppm; Kong et al, 1997) are much higher than for the highly metamorphosed EL5,6 chondrites (6 ppm; Kong et al, 1997).…”

Section: Introductionmentioning

confidence: 98%

Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes

Moynier

Paniello

Gounelle

et al. 2011

Geochimica et Cosmochimica Acta

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Thermal metamorphism of primitive meteorites—XL The enstatite meteorites: origin and evolution of a parent body

Cited by 60 publications

References 37 publications

Solar wind and other gases in the regoliths of the Pesyanoe parent object and the moon

Solar wind and other gases in the regoliths of the Pesyanoe parent object and the moon

Achondrites

Nature of volatile depletion and genetic relationships in enstatite chondrites and aubrites inferred from Zn isotopes

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