de.mpg.escidoc.pubman.appbase.FacesBean
Deutsch
 
Hilfe Wegweiser Impressum Kontakt Einloggen
  DetailsucheBrowse

Datensatz

DATENSATZ AKTIONENEXPORT

Freigegeben

Zeitschriftenartikel

The relative formation ages of ferromagnesian chondrules inferred from their initial aluminum-26/aluminum-27 ratios

MPG-Autoren
http://pubman.mpdl.mpg.de/cone/persons/resource/persons101147

Mostefaoui,  S.
Cosmochemistry, Max Planck Institute for Chemistry, Max Planck Society;

Externe Ressourcen
Es sind keine Externen Ressourcen verfügbar
Volltexte (frei zugänglich)
Es sind keine frei zugänglichen Volltexte verfügbar
Ergänzendes Material (frei zugänglich)
Es sind keine frei zugänglichen Ergänzenden Materialien verfügbar
Zitation

Mostefaoui, S., Kita, N. T., Togashi, S., Tachibana, S., Nagahara, H., & Morishita, Y. (2002). The relative formation ages of ferromagnesian chondrules inferred from their initial aluminum-26/aluminum-27 ratios. Meteoritics and Planetary Science, 37(3), 421-438.


Zitierlink: http://hdl.handle.net/11858/00-001M-0000-0014-9140-E
Zusammenfassung
We performed a systematic high-precision secondary ion mass spectrometry Al-26-Mg-26 isotopic study for 11 ferromagnesian chondrules from the highly unequilibrated ordinary chondrite Bishunpur (LL3.1). The chondrules are porphyritic and contain various amounts of olivine and pyroxene and interstitial plagioclase and/or glass. The chemical compositions of the chondrules vary from FeO-poor to FeO-rich. Eight chondrules show resolvable Mg-26 excesses with a maximum delta(26)Mg of similar to1% in two chondrules. The initial Al-26/Al-27 ratios inferred for these chondrules range between (2.28 +/- 0.73) x 10(-5) to (0.45 +/- 0.21) x 10(-5). Assuming a homogeneous distribution of Al isotopes in the early solar system, this range corresponds to ages relative to CAIs between 0.7 +/- 0.2 Ma and 2.4(+0.7)(-0.4) Ma. The inferred total span of the chondrule formation ages is at least I Ma, which is too long to form chondrules by the X-wind. The initial Al-26/Al-27 ratios of the chondrules are found to correlate with the proportion of olivine to pyroxene suggesting that olivine-rich chondrules formed earlier than pyroxene-rich chondrules. Though we do not have a completely satisfactory explanation of this correlation we tentatively interpret it as a result of evaporative loss of Si from earlier generations of chondrules followed by addition of Si to the precursors of later generation chondrules.