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  • 1
    Publication Date: 2020-12-22
    Description: A study of six tephra layers discovered in different deposits between 1600 and 2700 m a.s.l. in the Apennine chain in central Italy allowed precise stratigraphic constraints on environmental and climatic changes between ca. 4.5 and 3.8 cal ka BP. Chemical analyses allowed the correlation of these tephra layers with the eruptions of Agnano Mt Spina (AMST) from Phlegrean Field and Avellino (AVT) from Somma–Vesuvius. Major environmental changes in the high mountains of the Central Apennines occurred just after the deposition of the AMST and predate the deposition of the AVT. At this time, renewed growth of the Calderone Glacier occurred, marking the onset of the Apennine “Neoglacial”. The presence of the AMST and AVT enabled us to make a precise, physical correlation with other archives in central Italy. Synchronization of records between sites showed that the period intervening the deposition of the AMST and AVT layers coincided with environmental changes that were not always exactly in phase. This highlights the fact that stratigraphic correlations using only radiocarbon chronologies (the most common method used for dating archives during the Holocene) could produce erroneous correlation of events, giving rise to oversimplified paleoclimatic reconstructions.
    Description: Published
    Description: 236-247
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: restricted
    Keywords: Tephrostratigraphy ; Holocene ; Central Italy ; Paleoclimate ; 03. Hydrosphere::03.01. General::03.01.99. General or miscellaneous ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2021-06-16
    Description: One of the principal reasons why speleothems are recognised as important palaeoclimate archives is their suitability for accurate and precise uranium-series (U-series) age determination. Sampling speleothem sections for U-series dating is straightforward in most cases because visible growth layers are preserved. However, this is not always the case, and here we describe a sampling strategy whereby growth layers are resolved from trace-element images produced by laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). We apply this method to a section of an Italian subaqueous speleothem (CD3) that lacks persistent visible growth layering. Trace-element imaging revealed growth layers that are strongly non-planar in their geometry owing to the speleothem's pronounced euhedral crystal terminations. The most prominent trace-element layers were first digitized as x, y vector contours. We then interpolated these in the growth-axis direction to generate a series of contour lines at ∼250-μm increments. The coordinates of these contours were used to guide the sampling via a computerised micromilling lathe. This produced a total of 22 samples for U-series dating by multi-collector ICP-MS. The dating results returned ages in correct stratigraphic order within error. Close inspection of the U-series data and the derived depth–age model suggests that the main source of model-age uncertainty is unrelated to the contour sampling but instead more associated with how closely spaced the model ages are in time, i.e. the model age density. Comparisons between stable oxygen and carbon isotope profiles derived from aliquots of the dating samples and two other stable isotope profiles from CD3 spanning the same time period compare very favourably. Taken together, this suggests that our trace-element contouring method provides a reliable means for extracting samples for dating (and other geochemical analyses), and can be applied to similar speleothems lacking visible growth layering.
    Description: Published
    Description: 38-47
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: reserved
    Keywords: Speleothems ; U–Th dating ; Growth layers ; LA-ICP-MS ; Trace elements ; Microsampling ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2021-06-16
    Description: In this work we present the results of a stratigraphic and lithologic study of a flowstone from Tana che Urla Cave, Apuan Alps (central Italy) which grew intermittently between ca. 160 and 8 ka. The studied succession consists of an alternation of two different lithofacies (Lf-A, Lf-B): a brown, detrital-rich (Lf-A) and a white, inclusion-poor calcite (Lf-B). Using available growth rate data, the difference between the two lithofacies is thought to be the result of different amounts of meteoric precipitation, with Lf-A related to low growth rates at times of low precipitation during phases of climatic deterioration (stadial or glacial) and a higher flux of clastic material, and Lf-B related to high growth rates due to high infiltration under conditions of higher precipitation during wetter (interstadial/interglacial) periods, with lower clastic flux. Following this interpretation and the available chronology, the flowstone investigated shows a basal portion of Lf- A that was deposited during MIS6. The flowstone then passed from Lf-A to Lf B at the MIS6-5 transition, with Lf-B lasting for the full interglacial of MIS5e. A long growth interruption (hiatus H1) can be correlated with the MIS5d stadial, with resumption of lithofacies Lf-B occurring during the climatic amelioration of interstadial MIS5c. The age profile of the upper part of the flowstone is poorly constrained, and is characterised by several growth interruptions, suggesting that the last glacial was more severe compared to MIS6.
    Description: Published
    Description: 141-152
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: JCR Journal
    Description: restricted
    Keywords: speleothem ; paleoclimate ; stratigraphy ; petrography ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 04. Solid Earth::04.04. Geology::04.04.02. Geochronology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2022-08-25
    Description: The Monte Corchia cave system, one of the most famous and popular caves in Italy, has in recent times been the subject of investigation on its speleothems as paleoclimate archives. This paper describes the geology, geomorphology and water chemistry of the cave system with the aim to elucidate the processes that have generated these speleothems and the properties they contain that are so useful for paleoclimatology. Some general conclusions can be drawn: i) the Corchia system is a cave developed over different altitudes during progressive uplift of the mountain chain in which it is located, probably under drainage conditions very different to those of the present. This has allowed the development of a large (ca. 60 km) and deep (-1187 m) karst system; ii) the dewatering phases have left the deepest chambers far away from clastic input and with long drip pathways; iii) the peculiar geological context has permitted the water to intercept and dissolve a significant source of U (still unknown) that facilitates radiometric dating; iv) in the last 1 Ma at least, no significant changes have occurred in the relief and in the epikarst, in the sense that speleothems have grown under very similar conditions. In addition the extremely low Ca concentration of drip waters have permitted low speleothem growth rates and, at least for the “Galleria delle Stalattiti”, the zone under paleoclimate studies, a stable plumbing system (i.e. chemistry and stable isotopes of drip waters) has produced calcite close to isotopic equilibrium.
    Description: Published
    Description: 153-172
    Description: 3.7. Dinamica del clima e dell'oceano
    Description: N/A or not JCR
    Description: reserved
    Keywords: speleothems ; karst geomorphology ; cave water chemistry ; Corchia cave system ; Apuan Alps ; Central Italy ; 03. Hydrosphere::03.01. General::03.01.06. Paleoceanography and paleoclimatology ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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