Noble gases in enstatite chondrites II: The trapped component

Patzer, A.; Schultz, L.

doi:10.1111/j.1945-5100.2002.tb00841.x

Cited by 51 publications

(82 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Introductionsupporting

confidence: 88%

“…4) (El Goresy et al, 1988). This and the suggestion that ALH84206 is one of the most primitive E3 chondrites (Zhang et al, 1995) are consistent with the trend found by Patzer and Schultz (2002 Br (Marti et al, 1966), suggesting the presence of neutron-induced Kr. …”

supporting

confidence: 90%

“…These results therefore support the suggestion that sub-Q gases are elementally fractionated Q-gases (Patzer and Schultz, 2002). Patzer and Schultz (2002) found from noble gas measurements of 57 E chondrites that only five E3 chondrites show solar noble gas signatures. We have studied noble gases in solar-gas-bearing E3 chondrites so as to reveal the regolith evolution of E chondrite parent bodies (Nakashima and Nakamura, 2003;Nakashima et al, 2006b).…”

supporting

confidence: 88%

“…Enstatite (E) chondrites are known to show two distinct signatures of primordial noble gases: subsolar gases in E4-6 chondrites ( 36 Ar/ 132 Xe = 2660; South Oman EH4/ 5; Crabb and Anders, 1981) and sub-Q gases in E3 chondrites ( 36 Ar/ 132 Xe = 37 ± 18; Patzer and Schultz, 2002). Patzer and Schultz (2002) suggested that sub-Q gases are products of elemental fractionation of Q-gases ( 36 Ar/ 132 Xe = 50-100; Busemann et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Trapped noble gas components and exposure history of the enstatite chondrite ALH84206

Nakashima

Nakamura

2006

Geochem. J.

View full text Add to dashboard Cite

Noble gases in the Allan Hills (ALH) 84206 EH3 chondrite were measured with stepwise heating of a large sample (98.9 mg) and with total extraction of small samples (0.9-2.3 mg). Light noble gases show solar and cosmogenic components. The elemental ratios of solar gases in the samples suggest no significant loss of solar 36 Ar. Some of small samples are richer in cosmogenic 21 Ne than the large sample. Assuming that the excesses are due to a parent body exposure to cosmic rays, we obtain a parent body exposure age longer than 51 Ma and a meteoroid exposure age shorter than 39 Ma. Heavy noble gases are dominated by elementally fractionated Q-gases and atmospheric noble gases. The presence of fractionated Q-gases combined with no loss of solar 36 Ar suggests that solar wind exposure occurred after Q-gas fractionation. Kr isotopic ratios show the presence of neutron-induced 80 Kr and 82 Kr from Br. The minimum radius of the ALH84206 meteoroid was calculated as 27 cm from the abundances of neutron-induced Kr, assuming that these were produced during exposure of the meteoroid.Keywords: enstatite chondrite, regolith breccia, solar noble gas, primordial noble gas, cosmic-ray exposure age etrates 1 m or so (Walker, 1980), and produces cosmogenic noble gases via spallation reactions with target elements. Grains at the surface regolith are mixed by repeated impacts of cosmic dust and meteoroids (Housen et al., 1979) and acquire solar and cosmogenic noble gases. Cosmic dust bombardment produces tiny iron particles on the surface of the silicate grains via reduction of FeO (Sasaki et al., 2001), which results in darkening of regolith grains (Keller and McKay, 1997). Thus, the grains of the surface regolith darken and are loaded with the solar and cosmogenic noble gases (i.e., irradiated grains). The deeper sited grains below GCR active zone acquire neither solar nor cosmogenic noble gases (i.e., unirradiated grains). After the admixture of unirradiated grains to irradiated grains and residence in a deep site to which even GCR can not penetrate, all the grains within a meteoroid are ejected from the parent body upon a large-scale impact. During transit to the earth, all the grains accumulate cosmogenic noble gases by the exposure to GCR. Although the meteoroid is exposed also to SW and SEP, solar particles implanted on the meteoroid surface are lost during atmospheric entry. Thus, light portions contain only cosmogenic noble gases due to shielding from the solar radiation. Dark portions contain solar and cosmogenic noble gases, and have been part of the sur- INTRODUCTIONA subset of brecciated meteorites contains solar noble gases (Suess et al., 1964;Signer, 1964), indicative of direct exposure to the solar wind. It is generally agreed that the brecciated meteorites originate from surface regoliths of parental asteroids (Wänke, 1965;Lal and Rajan, 1969;Pellas et al., 1969;Wilkening, 1971;Pellas, 1972;Schultz et al., 1972;Rajan, 1974;Anders, 1975;Housen et al., 1979;Keil, 1982;Goswami et al., 1984). Such brecciated meteori...

show abstract

Section: Introductionsupporting

confidence: 88%

supporting

confidence: 90%

supporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Trapped noble gas components and exposure history of the enstatite chondrite ALH84206

Nakashima

Nakamura

2006

Geochem. J.

View full text Add to dashboard Cite

show abstract

“…This figure clearly illustrates that the xenon in carbonaceous chondrites is mainly carried in two solids: the phase Q and pre-solar grains, although phase Q is volumetrically by far the dominant component. Phase Q is observed in all chondrites (ordinary, carbonaceous and enstatite) (e.g., Schelhass et al, 1990;Patzer and Schultz, 2002;Okazaki et al, 2010).…”

Section: Figure 26mentioning

confidence: 99%

Noble gas constraints on the origin and evolution of Earth’s volatiles

Moreira¹

2013

GeochemPersp

118

164

View full text Add to dashboard Cite

Origin of Light Noble Gases (He, Ne, and Ar) on Earth: A Review

Péron

Moreira

Agranier

2018

Geochem Geophys Geosyst

View full text Add to dashboard Cite

We review the different scenarios for the origin of light noble gases (He, Ne, and Ar) on Earth. Several sources could have contributed to the Earth's noble gas budget: implanted solar wind, solar nebula gas, chondrites, and comets. Although there is evidence for “solar‐like” neon in the Earth's mantle, questions remain as to its origin. A new compilation of noble gas data in lunar soils, interplanetary dust particles, micrometeorites, and solar wind allows examination of the implanted solar wind composition, which is key to understanding the “solar‐like” mantle neon isotope composition. We show that lunar soils that reflect this solar‐wind‐implanted signature have a 20Ne/22Ne ratio very close to that of ocean island basalts. New data and calculations illustrate that the measured plume source 20Ne/22Ne ratio is close to the primitive mantle ratio, when taking into account mixing with the upper mantle (that has lower 20Ne/22Ne ratio). This favors early solar wind implantation to account for the origin of light volatiles (He, Ne, and possibly H) in the Earth's mantle: they were incorporated by solar wind irradiation into the Earth's precursor grains during the first few Myr of the solar system's formation. These grains must have partially survived accretion processes (only a few percent are needed to satisfy the Earth's budget of light volatiles). As for the atmosphere, the neon isotope composition can be explained by mixing 36% of mantle gases having this solar‐wind‐implanted signature and 64% of chondritic gases delivered in a late veneer phase.

show abstract

Noble gases in enstatite chondrites II: The trapped component

Cited by 51 publications

References 46 publications

Trapped noble gas components and exposure history of the enstatite chondrite ALH84206

Trapped noble gas components and exposure history of the enstatite chondrite ALH84206

Noble gas constraints on the origin and evolution of Earth’s volatiles

Origin of Light Noble Gases (He, Ne, and Ar) on Earth: A Review

Contact Info

Product

Resources

About