The loess-paleosol sequence at Monte Netto: a record of climate change in the Upper Pleistocene of the central Po Plain, northern Italy

Abstract

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

Progressive offset and surface deformation along a seismogenic blind thrust in the Po Plain foredeep (Southern Alps, Northern Italy)

“…(2 σ ), corresponds to the upper and very poorly weathered silt deposit, which is interpreted as a final phase of loess deposition, probably dating to Lateglacial stadials preceding the Bølling‐Allerød. Sample CAP03 was collected from a weakly developed soil on loess and possibly represents the age of a soil developed under glacial conditions in a tundra steppe environment with prolonged accumulation of organics and microcharcoals and later isolated from the surface; it therefore represents a mean value for the time of soil development [ Zerboni et al ., ]. This result is comparable to the cumulic soil described at the top of the Val Sorda loess sequence [ Cremaschi et al ., ; Ferraro , ], not far from Monte Netto.…”

“…For a detailed description of the pedostratigraphic and sedimentological characteristics of this sequence, which is beyond the scope of the present work, please refer to the companion paper by Zerboni et al . [].…”

“…Samples CAP01 and CAP02 gave Holocene ages for the upper part of the sequence (7483–7287 and 5574–5094 cal years B.P.). These young radiocarbon ages possibly reflect anthropogenic reworking of the loess and the Holocene soil developed on it and postdate loess deposition [ Zerboni et al ., ].…”

Lashed by the wind: short-term Middle Palaeolithic occupations within the loess-palaeosoil sequence at Monte Netto (Northern Italy)

“…Among isolated hills, particularly important are the Castenedolo and Monte Netto hills, which are located in the alluvial plain south of Brescia. These hills have been affected by repeated loess depositions during Marine Isotope Stages (MIS) 4-2 that sealed Mousterian open air sites (Baroni, 1986;Baroni et al, , 1988 https://doi.org/10.1016/j.quaint.2019.01.026 Received 13 August 2018; Received in revised form 6 January 2019; Accepted 21 January 2019 Cremaschi, 1974;Livio et al, 2012Livio et al, , 2014Zerboni et al, 2015).…”

“…On the top of the Monte Netto Hill (Capriano del Colle, BS), Mauro Cremaschi (1974) uncovered archaeological materials dating back to different Palaeolithic phases. Furthermore, a recent survey in a quarry site (Zerboni et al, 2015) allowed the identification, again on the top of the hill, of an open-air Middle Palaeolithic context, buried and preserved by a loess sheet, and occasionally older archaeological materials. This contribution illustrates the archaeological discovery discussing the paleoenvironmental and the taphonomic contexts and offering the contextualization of the site at a regional level.…”