THE RICHFIELD LL3 CHONDRITE

Richfield is a moderately shocked (shock stage S4) LL3.7 genomict brec cia find consisting mainly of light-colored recrystallized clasts and dark clasts exhibiting significant silicate darkening; a few impact-me lt-rock clasts and LL5 chondrite clasts also occur. The cosmic-ray exp osure age of 14.5 Ma is indistinguishable from the main exposure peak for LL chondrites (15 Ma). Although the exposure ages indicate little He loss, the gas-retention ages indicate high gas losses that must hav e occurred prior to or during ejection from the LL parent body.