[meteorite-list] Chelyabinsk - cosmic-ray exposure age

[Bernd V. Pauli]

Hello Martin and List,

Martin inquires:

"according to ITAR-TASS the cosmic-ray exposure ... age of Chelyabinsk
is reported to be 289 million years,...is this a typo and it is rather
28.9 million years?"

That would be my uneducated guess. Here are some CRE ages
for LL4 chondrites (Chelyabinsk is an LL4 !) culled from
Graf Th. (1994):

07.2 - Sevilla
13.6 - Kelly
15.8 - Benares (a)
17.3 - Savtschenskoje
39.1 - Albareto
40.6 - Hamlet
41.6 - Bo Xian
71.1 - Soko-Banja

Reference:

GRAF TH. et al. (1994) Collisional records in LL chondrites including
noble gas data and exposure ages (Meteoritics 29-5, 1994, 643-648).

Cheers,

Bernd