THE LATE LOWER PLIOCENE PLANATION SURFACE AND MOUNTAIN BUILDING OF THE APENNINES (ITALY)

Abstract

Investigations on the nature, age and lateral relationships of the remnants of Italian planati on surfaces indicate that: 1) a single planation surface (PS) is recognisable across the Apennines along the inner part of the Italian Peninsula; 2) it was originally very flat; 3) it is better preserved on harder rocks and is not preserved on the higher relief because of major uplift and consequent dissection or glacial erosi on; 4) it cuts terrain ranging in age from Palaeozoic to early Lower Pliocene; 5) it planated the tectonic structures developed in earlier times; 6) it is at places buried under continental and mari­ne deposits younger than late Lower Pliocene; 7) the PS was eroded in a much shorter time than is usually assumed; 8) the PS was mode­led during the climatic amelioration that generated the Late Lower Pliocene transgression and largely corresponds to a plain of marine erosion; 9) after the end of Lower Pliocene it was uplifted and deformed by very limited re-activation of thrusts; 10) since the Lower Pleistocene it was displaced by high angle normal faults. [...]