ABSTRACT: Quaternary Structure of the Southern Po Plain (Italy): Eustatic and Tectonic Implications

Enzo Farabegoli, Giuseppe Onorevoli

The Quaternary telescoped growth pattern of the Southern Po Plain developed during the last 250,000 yr through the superimposition of six fining-upward continental sequences, which can be correlated with terraced deposits.

The boundary surfaces of every cycle (base and top of gravels and/or sands), the overall thickness, the thickness of basal coarse sediments, and the related trends and deviations have been computer-gridded and contoured.

Comparison between the maps of the whole Quaternary sequence and the structural map of Pliocene isobaths suggests that the sequence evolution has been controlled by the combined action of glacio-eustatic fluctuations and strong tectonics. Lowstands controlled the regional pattern of the basal surfaces, and highstands coincide with the time of accretions of the sequences. Tectonics influenced the local subsidence, and consequently, the paleogeographic setting, following a rather regular cyclic trend. Four tectonic events alternated with four pauses; each period was 20,000-50,000 years long.

Thrust kinematics proceeded cyclically from the inner to outer thrust faults, giving rise to isolated, grouped and joined, and grouped but free tectonic elements.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990