Showing papers by "Toshiko K. Mayeda published in 1978"
TL;DR: The main group pallasites and the mesosiderites fall within the oxygen isotope group previously determined for the calcium-rich achondrites (eucrites, howardites and diogenites), consistent with derivation from a common source material, and perhaps a common parent body as discussed by the authors.
95 citations
TL;DR: In three brecciated meteorites, Bencubbin, Cumberland Falls and Plainview, the oxygen isotopic compositions of different rock types within each meteorite were determined to seek genetic relationships between them as discussed by the authors.
41 citations
01 Jan 1978
TL;DR: The variations of Si-30/Si-28 and Si-29/Si28 in Allende inclusions are large, and are due predominantly to mass-dependent fractionation effects as discussed by the authors.
Abstract: The variations of Si-30/Si-28 and Si-29/Si-28 in Allende inclusions are large, and are due predominantly to mass-dependent fractionation effects. Gas-soild or gas-liquid condensation processes at high temperatures have sufficiently large fractionation factors to account for the heavy-isotope enrichments in coarse-grained inclusions. Heavy isotope depletions are found in some Allende samples, and apparently result from a late-stage condensation. Thus, the silicon isotopic compositions may be useful for determining the sequence of events in forming the Allende meteorite. The peculiar Allende inclusion, Cl, has a very large mass-fractionated enrichment of Si-30/Si-28, and in addition, perhaps a small nuclear enrichment of Si-29. Olivine from the unusual pallasite, Eagle Station, has normal silicon isotope abundances even though it has a large O-16 excess.
35 citations
Journal Article•
3 citations