Xe-129 - Xe-128 and Ar-40 - Ar-39 chronology of two Antarctic enstatite meteorites

• Main Authors: Honda, M., Bernatowicz, T. J., Podosek, F. A.
• Format: Other/Unknown Material
• Language: unknown
• Published: 1983
• Subjects: 91; Antarctic; Antarc*
• Online Access: http://ntrs.nasa.gov/search.jsp?R=19850065194

Xe-129 - Xe-128 and Ar-40 - Ar-39 analyses has been performed on two Antarctic enstatite meteorites, the chondrite Y-691 and the aubrite (enstatite achondrite) ALH-78113. Both meteorites have complex Ar-40 - Ar-39 release patterns to which no unambiguous age assignment is possible. Both give apparently satisfactory Xe-129 - Xe-128 correlations corresponding to unusual ages. The I-Xe age of the chondrite Y-691 is 16 Ma after Bjurbole, not unusual for chondrites in general but 10 Ma later than previously known ages for enstatite chondrites. The I-Xe age of the aubrite ALH-78113 is 210 Ma after Bjurbole, the latest age (rather than a limit) so far observed by the I-Xe technique, but this age assignment must be considered tentative because of the possibility that it is significantly influenced by terrestrial I contamination.