Were CM Chondrites Aqueously Altered in the Quiescent Interior of Their Parent Body?

Several lines of evidence suggest that CM chondrite materials might sample a relatively thin asteroidal regolith that was subjected to both aqueous alteration and periodic episodes of mechanical mixing by impacts. Petrologic observations of CM chondrites, mostly of delicate aqueous alteration features, are presented that are more easily reconciled with an alternative scenario: that CM materials were aqueously altered at depth in the CM asteroidal parent body after brecciation and that they remained in this unenergetic environment throughout the compaction and lithification process.