On the depth-dependent production of long-lived spallogenic53Mn in the St. Severin chondrite

The contents of spallogenic⁵³Mn and target elements for its production were determined in 80- to 400-mg samples from 13 different locations of the LL6 chondrite St. Severin, along the 34.8-cm drill core AIII. The⁵³Mn content increases from the surface to the center of the stone by ≈30%. The variation with depth is satisfactorily described by several models, presuming that appropriate primary and secondary particle fluxes are chosen. The⁵³Mn saturation activities (⁵³Mn^*) are linearly correlated with the spallogenic³He/²¹Ne and²²Ne/²¹Ne ratios, which suggests the possibility to eliminate uncertainties in the determination of⁵³Mn cosmic ray exposure ages arising from depth effects and terrestrial residence times.