Influence of glacial cycles and tectonics on natural subsidence in the Po Plain (Northern Italy): Insights from ¹⁴C ages

Samples rich in organic matter were collected from boreholes in the southern part of the Po Plain (Italy), a rapidly subsiding sedimentary basin. New 14 C dates, obtained from these samples, and 14 C data from the literature allowed for the evaluation of the rates of natural subsidence in the area. These range from 0 to 5 mm/yr. Most areas show rates around 1 and 2 mm/yr. The obtained subsidence rates are comparable with burial rates obtained from archaeological data. These data are interpreted in terms of long‐term (related to tectonics and geodynamics) and short‐term (glacial cycle) processes. It is concluded that approximately 50% of the subsidence rates are related to tectonics, geodynamics and sediment load/compaction while the other half is controlled by ice melting. The effects of the glacial cycle through time are discussed. It is shown that the southeastern Po Plain generally behaves as a far‐field area in relation to the high‐latitude ice caps. Deviations from this behavior observed in the northeastern part of the Po Plain are tentatively interpreted as the effects of ice formation and melting in the Alps during the last glacial cycle.