Abstract
Widespread uppermost Miocene conglomerate and sandstone along the Apenninic-Maghrebian orogenic belt in the central Mediterranean region cannot be explained as a result of the Messinian base-level falls. Along the Ionian coast of Calabria, southern Italy, these rocks were deposited in marine fan deltas and rest in angular unconformity or disconformity upon the internal part of the Calabrian accretionary wedge. We propose that the upper Messinian deposits were produced by internal shortening of the Calabrian accretionary wedge as it compensated for the decrease in upper surface slope caused by flexural rebound as the ∼3.4-km-thick Ionian water mass evaporated. Latest Miocene-Pliocene marine inundation reloaded the basin, restored the wedge to a critical state, and caused the rear part of the wedge again to become tectonically stable. This isostatically driven mechanism could explain widespread latest Messinian thrust faults and coarse siliciclastic deposits along much of the Apenninic-Maghrebian orogen.
