Exposure history of the regolithic chondrite Fayetteville: I. Solar-gas-rich matrix

Wieler, R.; Baur, H.; Pedroni, A.; Signer, P.; Pellas, P.

doi:10.1016/0016-7037(89)90076-8

Cited by 66 publications

(95 citation statements)

References 16 publications

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“…The chemical compositions of the samples are shown in Table 1 along with K and Ca concentrations measured by Pedroni (1 989). Within uncertainties, the major target element abundances determined as part of this work agree with those measured by Pedroni (1989). The agreement between our bulk chemical measurements and those of Pedroni (1989) verifies that noble gas and radionuclide measurements were performed on splits of nearly identical material.…”

Section: Experiments and Resultssupporting

confidence: 74%

“…Within uncertainties, the major target element abundances determined as part of this work agree with those measured by Pedroni (1989). The agreement between our bulk chemical measurements and those of Pedroni (1989) verifies that noble gas and radionuclide measurements were performed on splits of nearly identical material. The Be, Al, and CI were then chemically isolated from each sample and purified for accelerator mass spectrometry (AMS) measurement using a combination of ion chromatographic and solvent extraction techniques (Nishiizumi et af., 1984a,b).…”

Section: Experiments and Resultssupporting

confidence: 74%

“…Clasts 3/C 1 and 3/C2 are foreign inclusions of C 1 -C2 chondritic material; clast 38 is a eucritic xenolith. Mtx 3/C1/3 and Mtx 3183.4 are each howardite breccia matrix and were proximal to clasts 3/C 1 and 38, respectively (Pedroni, 1989). The goal of the sample selection was to use the combination of noble gas data and petrographic considerations to exemplify any complex exposure; the 2lNe measurements of Pedroni (1989) show significant variations between clasts suggesting a complex history.…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…The samples selected for radionuclide measurements were aliquots of those initially isolated for noble gas measurements (Pedroni, 1989). Clasts 3/C 1 and 3/C2 are foreign inclusions of C 1 -C2 chondritic material; clast 38 is a eucritic xenolith.…”

Section: Experiments and Resultsmentioning

confidence: 99%

“…A subsequent goal is to ascertain whether the 4n exposure was immediately preceded by a 2n exposure. This investigation will utilize measurements of multiple radionuclides, loge (tl/2 = 1.5 Ma), 26Al (0.705 Ma), 36Cl (0.301 Ma), and 53Mn (3.7 Ma), on splits of samples previously analyzed for cosmogenic 2lNe (Pedroni, 1989). Neon-21 is stable and therefore integrates a sample's entire exposure to energetic particles.…”

Section: Introductionmentioning

confidence: 99%

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Exposure history of separated phases from the Kapoeta meteorite

Caffee

Nishiizumi

2001

Meteorit & Planetary Scien

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Abstract-The cosmogenic radionuclides, loBe, 26A1, 36Cl, and 53Mn were measured in selected clasts and matrix samples from the howardite Kapoeta. Previous measurements of cosmogenic 21Ne indicate higher cosmic-ray exposure ages for bulk samples than for some separated clasts or mineral separates. A possible interpretation for this difference in apparent exposure ages is a complex recent exposure history for Kapoeta. In this scenario some constituents are exposed to cosmic rays in a 2n geometry as part of a larger body immediately preceding its 4n exposure in a smaller body. To test this scenario we measured cosmogenic radionuclides in several clasts from Kapoeta. These measurements are consistent with a simple single-stage 4n exposure history during which the entire inventory of cosmogenic radionuclides was produced. Taken together, these data are most consistent with a single-stage 4n exposure lasting -3 Ma. This scenario is nevertheless consistent with models in which the exposure of some constituents o f Kapoeta to energetic particles occurred at an earlier time, as is indicated by 21Ne measurements. However, from our data we conclude that insubstantial quantities of cosmogenic radionuclides were inherited from this earlier irradiation; this earlier exposure to energetic particles must have predated the recent exposure by at least -10 Ma to allow for the decay of the long half-life cosmogenic radionuclides.

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Section: Experiments and Resultssupporting

confidence: 74%

Section: Experiments and Resultssupporting

confidence: 74%