Timing of metal–silicate differentiation in the Eagle Station pallasite parent body - 18/06/14
pages | 7 |
Iconographies | 4 |
Vidéos | 0 |
Autres | 0 |
Abstract |
The time of the metal–silicate differentiation of the Eagle Station pallasite (ESP) parent body was investigated using the 26Al–26Mg short-lived chronometer (half-life of 0.72Myr). The Mg isotope ratios were measured in ESP olivines by both MC–SIMS and HR-MC–ICPMS, allowing us to check the consistency between the results given by two different analytical protocols and data reduction processes. Results show that the two datasets are consistent, with a (δ26Mg*)av. value of –0.003 (±0.005)‰ (2 s.e., n=89). Such a value, associated with data from the 182Hf–182W short-lived systematics (half-life of 8.9Myr), indicates an ESP parent body metal–silicate differentiation occurring most likely at least at ∼2Ma, but possibly 4Ma, after CAI formation. From the 27Al/24Mg ratios measured in ESP olivines using MC–SIMS, the duration of the olivine crystallization process was inferred to have lasted over ∼275kyr if the core has differentiated as early as 2Ma after CAIs, while in the case of a core differentiation occurring 4Ma after CAIs, the silicate–silicate differentiation should have lasted for another 4Myr.
Le texte complet de cet article est disponible en PDF.Keywords : Eagle Station pallasite, 26Al–26Mg short-lived chronometer, Metal–silicate differentiation age
Plan
Vol 346 - N° 3-4
P. 75-81 - mars 2014 Retour au numéroBienvenue sur EM-consulte, la référence des professionnels de santé.
L’accès au texte intégral de cet article nécessite un abonnement.
Bienvenue sur EM-consulte, la référence des professionnels de santé.
L’achat d’article à l’unité est indisponible à l’heure actuelle.
Déjà abonné à cette revue ?