Purpose At the northern fringe of the Po Plain (northern\ud Italy), several isolated hills exist, corresponding to the top of Late Quaternary anticlines. These hills were thoroughly surveyed for their soils and surficial geology, furnishing detailed archives of the palaeoenvironmental evolution of the area. A new, thick and complex loess-paleosol sequence, resting upon fluvial/fluvioglacial deposits, exposed in a quarry at the top of the Monte Netto hill was studied in detail to elucidate its significance.\ud Materials and methods Highly deformed fluvial and\ud fluvioglacial deposits, probably of Middle Pleistocene age,\ud are exposed in a clay pit at Monte Netto, underneath a 2- to\ud 4-m-thick loess-paleosol sequence. A geopedological, sedimentological and micropedological investigation of the sequence shows a distinctive difference between the B horizons forming the sequence, while luminescence and radiocarbon age determinations and the occurrence of Palaeolithic lithic assemblages elucidate the chronology of the sequence.\ud Results and discussion The pedosedimentary sequence consists of several loess layers showing different degrees of\ud alteration; loess deposition and weathering occurred,\ud according to optically stimulated luminescence (OSL) and\ud AMS-14C dating as well as archaeological materials, during\ud the Upper Pleistocene. The lower part of the section consists\ud of strongly weathered colluvial sediments overlying fluvial\ud and fluvioglacial sediments. A tentative model of the exposed profiles involves the burial of the anticline, which forms the core of the hill, by loess strata since Marine Isotopic Stage (MIS) 4 and their subsequent weathering (and truncation) during subsequent interstadials. The degree of weathering of buried B horizons increases from the top of the sequence toward the bottom, suggesting a progressive decrease in the\ud intensity of pedogenesis. Finally, the highly rubified paleosol\ud at the top of the hill is regarded as a buried polygenetic soil or a vetusol, developed near the surface since the Middle\ud Pleistocene.\ud Conclusions The palaeopedological, geochronological and\ud geoarchaeological analyses permit to define the phases and\ud steps of development of the Monte Netto pedosedimentary\ud sequence; the lower part of the sequence is dated to the Mid-Pleistocene, whereas loess accumulation occurred between MIS 4 and MIS 2. Moreover, analyses help to clarify the climatic and environmental context of alternating glacial and interstadial phases, during which the sediments where deposited, deformed and weathered
Here we present, for the first time in the Po Plain foredeep (Northern Italy), the middle to late Pleistocene growth history of an outcropping secondary fold and related faults, whose progressive deformation over an intermediate time window (10 5 years) is driven by an underlying seismogenic blind thrust. We trenched and logged an outcropping decametric secondary anticline, related to a deeper blind compressional structure, which deforms fluvial sediments and an overlying loess-paleosol sequence. Folded units were dated, using radiocarbon and optically stimulated luminescence methods, to the late Pleistocene-Holocene and tentatively correlated with glacial-interglacial phases occurring during the time interval from marine isotope stage 6 to the present. A multistep retrodeformation of the fold allowed us to calculate uplift rates for this secondary and shallow anticline, varying between 0.02 and 0.1 mm/yr since circa 200 kyr. Trishear forward deformation modeling of the fold indicates that the amplification of the observed fold could be caused by two shallow thrusts formed through a break-backward activation. This generated a decametric surface fold whose most recent growth was associated with bending-moment normal faulting in the crestal and forelimb region. Our observations demonstrate that near-surface compressive tectonics can be caused by blind thrusting, via a complex array of fault and folds: upward strain propagation and generation of shallow low-angle thrust and related folding seem to be mainly due to secondary fold-related faulting, according to an out-of-syncline thrusting mechanism.
<p>Since May 16, 2012, a seismic sequence has affected a wide portion of the Emilia Region (northern Italy), chiefly for the Modena and Ferrara Provinces. The first mainshock (Ml 5.9; focal depth, ca. 6 km) occurred on May 20, 2012, with the epicenter located a few kilometers north of Finale Emilia. A second main shock (Ml 5.8; focal depth, ca. 10 km) occurred on May 29, 2012, about 12 km west of the first earthquake, with the epicenter near Medolla (Figure 1). The seismic sequence has been characterized by five other Ml ≥5 events, and more than 2,300 aftershocks of lower magnitude, until the end July 2012. The distribution of the aftershocks identifies a WNW-ESE-trending zone ca. 40 km long that is characterized by NNE-SSW nearly pure compression, as indicated by the focal mechanisms [e.g., QRCMT 2012]. This report focuses on the many ground effects that were induced by this seismic sequence, as mainly cracks, liquefaction-type phenomena, and hydrological anomalies. The aim is to provide a complete representation of such effects, to: illustrate their type, size and areal distribution; identify the zones in the affected area that were most prone to the occurrence of ground effects (i.e., more susceptible to local geological instability in the case of earthquake occurrence); carry out an independent assessment of the intensities of the earthquakes through the ESI 2007 intensity scale [Guerrieri and Vittori 2007], which is based only on coseismic effects on the natural environment. […]</p>
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