155,241 research outputs found
The Malacofauna of the Upper Paleolithic levels at Grotta della Serratura (Salerno, Southern Italy). Preliminary data
No full textLo studio dei molluschi del Paleolitico superiore della grotta della serratura presso Sapri, mette in evidenza i cambiamenti climatici e gli interessi economici del periodo.The study of molluscs from upper Palaeolithic layers of the Serratura cave near Sapri, show the climatic changes and economic interest of the period
Ricostruzione climatica e ambientale di grotta del Romito: Analisi palinologiche e malafaunistiche dei livelli epigravettiani C e D
No full textDeciphering late Quaternary land snail shell δ18 O and δ13 C from Franchthi Cave (Argolid, Greece)
No full textThis paper investigates the stable isotopic composition from late Pleistocene-Holocene (similar to 13 to similar to 10.5 cal ka BP) shells of the land snail Helix figulina, from Franchthi Cave (Greece). It explores the palaeoclimatic and palaeoenvironmental implications of the isotope palaeoecology of archaeological shells at the time of human occupation of the cave. Modern shells from around the cave were also analysed and their isotopic signatures compared with those of the archaeological shells. The carbon isotope composition of modern shells depicts the consumption of C-3 vegetation. Shell oxygen isotopic values are consistent with other Mediterranean snail shells from coastal areas. Combining empirical linear regression and an evaporative model, the delta Os-18 suggest that modern snails in the study area are active during periods of higher relative humidity and lower rainfall delta O-18, probably at night. Late glacial and early Holocene delta Os-18 show lower values compared to modem ones. Early Holocene delta Os-18 values likely track enhanced moisture and isotopic changes in the precipitation source. By contrast, lower late glacial delta O-18 could reflect lower temperatures and delta(18)Op, compared to the present day. Shell carbon isotope values indicate the presence of C-3 vegetation as main source of carbon to late glacial and early Holocene snails. (C) 2013 University of Washington. Published by Elsevier Inc. All rights reserved
Stable isotope composition of Late Glacial land snail shells from Grotto del Romito (Southern Italy): Palaeoclimatic implications
No full textStable isotope composition of living and fossil land snail shells was determined at Grotta del Romito (Southern Italy) with the aim to reconstruct environmental and climatic variation in the area during Late Upper Palaeolithic. The investigated succession comprised 15 different excavated layers spanning between ca 13,000 and 14,500 yr cal BP. The oxygen isotope composition of snail shells indicates a marked decrease at the layer D8 suggesting a climatic deterioration consistent with the GI 1d climatic event (Older Dryas). This climate deterioration may have been related to a substantial decrease of mean annual temperature with associated changes in the regional atmospheric circulation. However, the environmental conditions at the time of shell's growth in the other intervals sampled suggest condition comparable to the present day. The carbon isotope composition of fossil snail shells is in agreement with other records, which indicate a general increase of the δ13C values of organic matter during Pleniglacial to Late Glacial caused by substantially lower atmospheric CO2 concentration at that time
Middle Pleistocene (MIS 14) environmental conditions in the central Mediterranean derived from terrestrial molluscs and carbonate stable isotopes from Sulmona Basin (Italy)
No full textA paleosol from the Middle Pleistocene lacustrine-fluvial succession of Sulmona Basin, central Italy, was analysed for the land snail shell content, and the stable isotope composition of the shells and associated pedogenic carbonates. The paleosol – known as Fiorata Paleosol – is covered by a thick tephra layer dated to ca. 527 ka allowing the pedogenetic horizons to be correlated to the marine isotope stage (MIS) 14-early MIS 13 interval. The terrestrial mollusc assemblage contained few individuals and was characterized by a low number of species which predominantly indicate open and dry habitats, thus suggesting that Fiorata Paleosol likely developed during glacial conditions of the MIS 14. The δ13C values of pedogenic carbonates and terrestrial shells indicate prevailing C3-type vegetation, probably marked by some degree of water stress. Calculation of the δ18O precipitation values, derived from pedogenic carbonates and shell δ18O values, indicate that the average temperature was 3–5 °C lower than present day. This study highlights how paleosols, despite offering only snapshots of past climate and environments, provide valuable complementary information to paleoclimatic data obtained in the adjacent lacustrine intervals, specifically for the Sulmona successions
Stable isotope composition of <i>Helix ligata</i> (Muller, 1774) from Late Pleistocene-Holocene archaeological record from Grotta della Serratura (Southern Italy): Palaeoclimtic implications
No full textCarbon and oxygen isotope ratios were measured in fossil and recent shells of the land snail Helix ligata.
Fossil shells were recovered from the archaeological excavations of Grotta della Serratura and recent
specimens collected adjacent to the cave. The record is discontinuous and spans from ca 14 to 7 ka cal BP.
The oxygen isotope composition of the fossil shells suggests they were grown from environmental waters
(e.g. precipitation) isotopically similar to the present during the recorded part of the Late Glacial. A notable
exception is represented by a layer at ca 13.4 ka cal BP, with shells characterised by 18O-enriched values,
suggesting drier conditions, with rainfall perhaps reduced by 25% compared to the present day. This layer
could correspond in part with the GI-1b event of the Greenland ice-core records. The onset of the Holocene
was marked by a decrease of δ18O, suggesting an increase in humidity. Significantly lower δ18O values occur
at ca 7.4 ka cal BP, in agreement with other stable isotope records, which suggests enhanced rainfall over the
Mediterranean region at that time
Middle Pleistocene (MIS 14) environmental conditions in the central Mediterranean derived from terrestrial molluscs and carbonate stable isotopes from Sulmona Basin (Italy)
No full textA paleosol from the Middle Pleistocene lacustrine-fluvial succession of Sulmona Basin, central Italy, was analysed for the land snail shell content, and the stable isotope composition of the shells and associated pedogenic carbonates. The paleosol - known as Fiorata Paleosol - is covered by a thick tephra layer dated to ca. 527ka allowing the pedogenetic horizons to be correlated to the marine isotope stage (MIS) 14-early MIS 13 interval. The terrestrial mollusc assemblage contained few individuals and was characterized by a low number of species which predominantly indicate open and dry habitats, thus suggesting that Fiorata Paleosol likely developed during glacial conditions of the MIS 14. The δ13C values of pedogenic carbonates and terrestrial shells indicate prevailing C3-type vegetation, probably marked by some degree of water stress. Calculation of the δ18O precipitation values, derived from pedogenic carbonates and shell δ18O values, indicate that the average temperature was 3-5°C lower than present day. This study highlights how paleosols, despite offering only snapshots of past climate and environments, provide valuable complementary information to paleoclimatic data obtained in the adjacent lacustrine intervals, specifically for the Sulmona successions
Aspetti climatici al passaggio Tardoglaciale-Olocene in Italia meridionale tirrenica desunti dalla composizione isotopica dei gusci di molluschi terrestri
No full textOxygen and carbon isotopic composition of modern terrestrial gastropod shells from Lipari Island, Aeolian Archipelago (Sicily)
No full textOxygen (δ18Os) and stable carbon (δ13Cs) isotopic compositions of modern terrestrial gastropod shells from
Lipari Island, in the Aeolian Archipelago (Sicily), have been analysed and compared with local meteoric water
δ18O (δ18Op) and vegetation δ13C (δ13Cv) respectively. Results reveal that the δ18Os–δ18Op relationship over
the study area differs from those obtained on continental Europe and Italian shells, implying that even at the
scale of the Mediterranean basin different relationships may co-exist. These differences have been interpreted
as the increasing influence of Mediterranean vapour water on Tyrrhenian coasts at relatively low altitude
(up to ~600 m asl), which compensates for the effect of the δ18Op, and possibly of temperature, on shell δ18O.
The steady-state flux balance model (FBM), in agreement with previous studies, suggests that snails are active
prevalently at night. Shell carbon isotope ratios reflect the δ13Cv, as predicted by the metabolic model and
represent a valuable tool for identifying C3 plants with very distinct isotopic signatures
Holocene snail shell isotopic record of millennial-scale hydrological conditions in western Mediterranean: data from Bauma del Serrat del Pont (NE Iberian Peninsula)
No full textLand snail shells are a common component in Mediterranean Holocene archaeological deposits, providing
the opportunity to explore their potential as source of information concerning human behaviour and
palaeoclimatic conditions. Many well-preserved shells of the caenogastropod Pomatias elegans were recovered
along the Holocene succession of Baumadel Serrat del Pont (BSP), in the Iberian Peninsula. Their oxygen
(d18Os) and carbon (d13Cs) isotopic compositions were analysed and compared with that of modern shells of
the samespecies collected intwo distinct areasnear the archaeological site.Modernshells fromSiteA(shady)
and B (sunny) show distinctly different oxygen isotopic ratios possibly due to the effect of microenvironmental
conditions (e.g. temperature and relative humidity). Carbon isotopes, by contrast, reveal
similar values. Isotope mass balance suggests a prevalent contribution of vegetation (w70%), integrated with
foreign carbonates (w30%) to d13Cs of modern snails. Earlyelate Holocene shells (w9e2.5 cal ka BP) have
lower d18Os compared with modern counterparts, which is consistent with prevailing wetter conditions
compared with present day. The d13Cs reveals distinct hydrological regimes, wet and dry conditions, from
early to late Holocene respectively. In general, shell isotopic records from western and central
Mediterranean regions suggest wetter conditions during the middle Holocene, with a possible reduction
in humidity from w4 cal ka BP. The d18Os indicates a possible latitudinal difference in hydrological balance
between Mediterranean and Atlantic Europe as inferred by previous studies of regional palaeoclimatic
records. Carbon isotopes, by contrast, do not provide a clear climatic picture, probably due to the effect of
distinct vegetation structure and composition. Comparisons with other environmental archives reinforce
the concept of regional shell oxygen isotopic response to millennial-scale changes in hydrological condition
over the western and central Mediterranean during the late Quaternary
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