The Predicted Irradiation Record of Asteroidal Regoliths and The

I INTRODUCTION The existence of regoliths on asteroidal surfaces is supported by recent telescopic observations. On the other hand the constituent grains of gas-rich meteorites have been clearly irradiated as individual grains in both the ancient solar wind (SW) and solar cosmic rays (SCR). This irradiation could have occured within an asteroidal regolith, before the compaction of the grains into a "brecciated" meteorite. The major purpose of this paper is to apply our analytical model of regolith evolution (1) for predicting the irradiation record of gas-rich meteorites in this case. It is shown that the comparison between the predicted and observed irradiation record gives useful clues about the origin of these interesting meteorites.