Detailed palaeo-vegetation reconstructions in southern Italy for the Late Pleistocene, based on pollen studies, have been published in the past decades. The pollen record of Lago Grande di Monticchio shows for 127.2-115.8 ka forest with Quercus and Mediterranean taxa; for 115.8- 109.5 ka forest with Abies, Alnus and Betula; for 109.5-107.6 ka high abundance of Betula and steppe taxa; for 107.60-90.65 ka temperate deciduous forest; for 90.65-87.98 ka Artemisia steppe; for 87.98-82.73 ka temperate deciduous forest; for 82.73-59.00 ka fluctuation, then Artemisia steppe; for 59.00-25.90 ka alternation between steppe (stadials) and wooded steppe (interstadials); for 25.90-14.30 ka steppe (LGM). Questions of our ongoing research are: Which soil features are related to Mediterranean climate, and which ones correspond to steppe environments during glacial periods? Can steppe soils be found in southern Italy? 26 soil profiles on marine terraces in Basilicata (Metaponto) and Calabria (Lazzaro) (Figs. 1, 2) were described and analyzed. In addition, buried soils in an alluvial fan in Calabria were studied. Soils on marine terraces, formed during the Last Interglacial period, are reddish-brown and show distinct clay coatings. Soils on older terraces become more reddish with age, whereas soils on loess and Holocene sediments are brown having no or very thin clay coatings only. Dark paleosols in the alluvial fan with evidence of high palaeo-bioturbation reflect periods of steppe environments (Figs. 3, 4). Such dark soils have not been preserved as surface soils on elevated marine terraces, although these terraces must have gone through periods of steppe environments as well. The soils were analyzed for pHH2O, pHKCl, texture, SOC, carbonate, Fed, and total elemental composition (XFA on fused discs). Clay mineral assemblage (XRD on oriented clay specimens) and micromorphology were analyzed on selected soil horizons. In the Lazzaro area, maximum Fed content is four times higher in the soil on the Last Interglacial terrace than in the surface soil on the alluvial fan (Figs. 5, 6). Fed values indicate pedogenetic cycles in the alluvial fan more clearly than SOM contents, which are not as high in the paleosols as might be expected due to their dark color. Low Fed contents and strong carbonate accumulation between 513 and 693 cm depth mark the driest period of this record. In general, Chernozem-like paleosols have been preserved only where they had been buried before the climate shifted again to a Mediterranean type. Otherwise, their organic matter was rapidly decomposed and the soils changed into reddish-brown Mediterranean soils.
Pleistocene soil development in Calabria and Basilicata, Southern Italy
SCARCIGLIA, Fabio;
2011-01-01
Abstract
Detailed palaeo-vegetation reconstructions in southern Italy for the Late Pleistocene, based on pollen studies, have been published in the past decades. The pollen record of Lago Grande di Monticchio shows for 127.2-115.8 ka forest with Quercus and Mediterranean taxa; for 115.8- 109.5 ka forest with Abies, Alnus and Betula; for 109.5-107.6 ka high abundance of Betula and steppe taxa; for 107.60-90.65 ka temperate deciduous forest; for 90.65-87.98 ka Artemisia steppe; for 87.98-82.73 ka temperate deciduous forest; for 82.73-59.00 ka fluctuation, then Artemisia steppe; for 59.00-25.90 ka alternation between steppe (stadials) and wooded steppe (interstadials); for 25.90-14.30 ka steppe (LGM). Questions of our ongoing research are: Which soil features are related to Mediterranean climate, and which ones correspond to steppe environments during glacial periods? Can steppe soils be found in southern Italy? 26 soil profiles on marine terraces in Basilicata (Metaponto) and Calabria (Lazzaro) (Figs. 1, 2) were described and analyzed. In addition, buried soils in an alluvial fan in Calabria were studied. Soils on marine terraces, formed during the Last Interglacial period, are reddish-brown and show distinct clay coatings. Soils on older terraces become more reddish with age, whereas soils on loess and Holocene sediments are brown having no or very thin clay coatings only. Dark paleosols in the alluvial fan with evidence of high palaeo-bioturbation reflect periods of steppe environments (Figs. 3, 4). Such dark soils have not been preserved as surface soils on elevated marine terraces, although these terraces must have gone through periods of steppe environments as well. The soils were analyzed for pHH2O, pHKCl, texture, SOC, carbonate, Fed, and total elemental composition (XFA on fused discs). Clay mineral assemblage (XRD on oriented clay specimens) and micromorphology were analyzed on selected soil horizons. In the Lazzaro area, maximum Fed content is four times higher in the soil on the Last Interglacial terrace than in the surface soil on the alluvial fan (Figs. 5, 6). Fed values indicate pedogenetic cycles in the alluvial fan more clearly than SOM contents, which are not as high in the paleosols as might be expected due to their dark color. Low Fed contents and strong carbonate accumulation between 513 and 693 cm depth mark the driest period of this record. In general, Chernozem-like paleosols have been preserved only where they had been buried before the climate shifted again to a Mediterranean type. Otherwise, their organic matter was rapidly decomposed and the soils changed into reddish-brown Mediterranean soils.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
