Late Quaternary unconformity-bounded stratigraphy of the northern Po Plain (Verona area) from subsurface data

Deciphering the subsurface architecture of Quaternary successions in glacially influenced environments represents a significant challenge, particularly in transitional settings where pronounced lateral variability and the common amalgamation of coarse-grained sedimentary bodies with similar facies characteristics may obscure stratigraphic boundaries. Within the framework of the CARG geological mapping project (Sheet 124 - “Verona Est”), we propose an updated stratigraphic framework for the upper 100 m of the eastern Verona plain (northern Po Basin), developed through the application of Unconformity-Bounded Stratigraphic Units (UBSUs). Our investigation builds upon a robust legacy dataset comprising 667 stratigraphic and geotechnical records, including continuous cores, water wells and cone penetration tests. This extensive database has been recently upgraded and integrated with seven newly acquired sediment cores, ranging from 30 to 85 m in length, specifically targeted to test preliminary stratigraphic models. We employed event-stratigraphy principles to discriminate between aggrading glacial outwash systems and incising fluvial systems associated with glacial-interglacial cycles. Within this framework, laterally continuous peat horizons, traceable across the entire study area, act as key regional stratigraphic markers and record the development of major stratigraphic unconformities. Furthermore, we tested a combined approach integrating classic stratigraphy method with geophysical exploration, involving the acquisition of a dense dataset of single-station ambient noise measurements. We aimed to build a geophysical cross-section based on the Horizontal-to-Vertical Spectral Ratio (HVSR) technique to highlight resonance frequency variations induced by near-surface stratigraphic heterogeneities. Finally, through the inversion of HVSR curves, constrained by Shear Wave Velocity (Vs) measurements and direct stratigraphic observation, we aim to determine the depth of major impedance contrasts to infer the architecture of the basin fill.