The Pleistocene tectono-stratigraphic evolution of the northern Po plain (Italy) around the Castenedolo-Ciliverghe hillocks

We studied the Pleistocene subsurface stratigraphy of an area in the northern Po Plain around the isolated tectonic hillocks of Castenedolo and Ciliverghe (Brescia, Italy) in order to estimate their long-term rates of tectonic deformation. Integrated stratigraphy of a new 100 m-long core (RL13) allowed to better define the regional Y (0.45Ma) and R (0.87 Ma) surfaces and the related magnetostratigraphically-calibrated PS1, PS2 and PS3 depositional sequences. Concerningthe RL13 core the Y surface was placed at the base of the PS3 proximal braided river system deposited during Middle Pleistocene within the Brunhes chron. The R surface is considered eroded within the PS2 braidplain deposits at ~0.87 Ma between the top of Jaramillo subchron and the Bruhnes chron during the late Early Pleistocene. Based on different datasets, we evaluated the sedimentation rate which has decreased from 0.09 mm/yr with the deposition of PS2, to 0.06 mm/yr with the deposition of PS3. The tectonic uplift with an average rate of ~0.1 mm/yr in the last ~0.87 Ma is interpreted associated to a fault and related fault-propagation folding. The Castenedolo and Ciliverghe hillocks are then formed due to tectonic uplift during a change in the sedimentation regime since 0.45 Ma.