New data on the Late-Pleistocene and Holocene evolution of eastern Campo Felice (Abruzzo - Central Italy)

Abstract

The studies of the Late Pleistocene and Holocene sediments forming the eastern portion of Campo Felice has allowed for the recognition of the environmental evolution of the area during the last 30,000 years ca. The infuence of the palaeoclimatic variations on the geological evolution can be inferred from glacial and fluvioglacial sediments and from lacustrine features and deposits. The developement of ponors in the southern margins of the area makes the interpretation of the significance of the lake level oscillations dated to the period between 15,290±50/15,270±50 years BP and 7760±50 years BP more difficult The oscillations of fake level that have produced the terraces at 1536 and 1530-31 m, still seem mainly due to the climatic variations. Later on, the ponors became more active and caused an abrupt lowering of the lake level and a strong lake reduction. A small residual lake was preserved in a limited portion of the former lake bed not draining towards the ponors. The reduction of the lake occurred before 7760±50 years BP. Also in the small and shallow lake, level oscillations had taken place, indicated by some shoreline remnants and erosional surfaces: from two of these surfaces one can infer phases of disappearance of the lake, dated to the period included between 7760+50 years BP and 3480±70/3680±90 years BP. The phases of disappearance and reapperance of the lake were due to the antagonism of two processes, namely the developement of an outflow directed towards the ponors and to its damming by means of the alluvial fan sediments. The antagonism was produced by alternating phases of dry and wet climate.