  Impact induced attrition processes are, beyond being essential models of
industrial ore processing, broadly regarded as the key to decipher the
provenance of sedimentary particles. A detailed understanding of single impact
phenomena of solid bodies has been obtained in physics and engineering,
however, the description of gradual mass reduction and shape evolution in
impact sequences relies on approximate mathematical models of mean field type,
formulated as curvature-driven partial differential equations. Here we
establish the first link between microscopic, particle-based material models
and the mean field theory for these processes. Based on realistic computer
simulations of particle-wall collision sequences, we first identify the
well-known damage and fragmentation energy phases, then we show that the former
is split into the abrasion phase with infinite sample lifetime, analogous to
Sternberg's Law, at finite asymptotic mass and the cleavage phase with finite
sample lifetime, decreasing as a power law of the impact velocity, analogous to
Basquin's Law. We demonstrate that only in the abrasion phase does shape
evolution emerging in microscopic material models reproduce with startling
accuracy the spatio-temporal patterns predicted by macroscopic mean field
approaches. Our results substantially extend the phase diagram of impact
phenomena and set the boundaries of the applicability of geometric mean field
theories for geological shape evolution. Additionally, the scaling laws
obtained can be exploited for quantitative predictions of evolution histories.
