The interactions among Quaternary (paleo-) soil-forming, erosion, re-deposition and geomorphic processes at the origin of the present-day landscape are discussed at three isolated tectonic reliefs of the Southern Po Foredeep Basin of Lombardy (San Colombano, Casalpusterlengo and Zorlesco reliefs, Italy). These sites offer the possibility to combine different scales of geopedological, geomorphological, stratigraphic and structural observations, to unravel the contribution of climate and tectonics to the Quaternary geological evolution and to the origin of the landscape.Field surveys, laboratory analyses and soil micromorphology were used to characterize the Late Quaternary pedogenic processes acting on different (paleo)surfaces, in combination with the detailed study of seven selected soil profiles. Pedo-stratigraphic correlations revealed that two alluvial/loess-paleosol sequences, which originated from the Late Pleistocene to Holocene glacial/interglacial fluctuations, are differently preserved throughout the present-day hill landscape. In situ paleosols allowed to localize the paleo-topographic surfaces of geomorphic, tectonic and sedimentary stabilization; redeposited paleosols, occurring systematically close to the main faults and/or at the erosional bottom of paleo-valleys, allowed to mark the stages of tectonic instability. The integrated approach contributed to unravel the composite nature and rank of the stratigraphic boundaries.Polycyclic loess-soil aggradation characterized the stable paleo-highs, uplifted during different phases of active thrusting of the northernmost Emilian arcs of the Apennine, while valley incision, fluvial terracing, soil truncation and redeposition occurred in the intervening structural lows. In the San Colombano hill area, Late Pleistocene transtensional faulting induced changes of the drainage network and enhanced redeposition of paleosols in colluvial wedges on the hangingwalls, along the fault scarps. LGM loess was preserved above different dissected remnants of the paleo-topography composing the hilltops. These new constraints permit to refine the Late Quaternary tectono-depositional history and landscape evolution at the southern margin of the Po Basin. This paper focuses on three tectonic reliefs which are close to the southern Po Basin margin, at the Apennine side, that are the San Colombano, Casalpusterlengo and Zorlesco relic reliefs (Fig. 1). They provide comprehensive case-studies on how erosion/sedimentation processes, soil forming
Optically Stimulated Luminescence (OSL) enables the chronology of the late Pleistocene evolution for the Val d'Agri intermontane basin of Southern Apennines to be defined in the frame of Mediterranean geodynamic and climate changes. Quartz sand from braided floodplain and alluvial fan depositional systems was analyzed using the coarse-grained, single-aliquot regenerative-dose (SAR) technique. The obtained optical ages are mostly consistent with other assessments (radiocarbon, tephrochronology) and stratigraphic constraints. OSL allows for the dating to 56–43 ka of an asymmetric subsidence stage that forced alluvial fan progradation, filling of a former lacustrine area, and development of an axial alluvial plain. A short period of Mediterranean-type pedogenesis, recorded at the top of the prograding-aggrading fans (OSL age bracket 43–32 ka), corresponds with MIS 3. During the subsequent stage of decline of vegetation cover, possibly corresponding to MIS 2, the latest progradation of alluvial fans occurred. The subsequent uplift and breakthrough of the basin threshold during the latest Pleistocene and Holocene induced entrenchment of the drainage network. The results presented here provide an example of the usefulness of OSL dating in intermontane continental settings where other geochronological constraints are scarce.
Loess deposits have been described in the past for the upper section of Buca Dei Corvi succession (Central Italy). In this paper the deposits were re-analysed to clarify the depositional environment and to attempt a paleoclimate reconstruction. Two radiocarbon dates on pedogenic carbonate constrain the ages to the Late Glacial, and are consistent with previous OSL dating of the top of the succession. The non-marine mollusc assemblage shows typical character of cold and dry climatic conditions, testified by strong oligotypical composition. Mineralogy and geochemistry of the sediments indicate the abundant presence of exotic quartz mineral which can be explained only by wind transport. Probably, wind transport was also responsible of deposition of carbonate which then dissolved and re-precipitated producing pedogenic concretions. Stable isotopes (13C/12C and 18O/16O ratios) of the concretions are consistent with a climate drier than present conditions, with an environment characterized by sparse vegetation
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