38 research outputs found

    Geochemistry and mineralogy of lacustrine sediment from Fucino Lake (Abruzzo, central Italy): palaeoclimatic and palaeoenvironmental implications.

    Get PDF
    Fucino basin is the largest intermountain tectonic depression of the central Apennines (Abruzzo, Italy). It hosts a thick and continuous succession of fine-grained lacustrine sediments interbedded with several fall-out deposits from the pery- Tyrrhenian Quaternary volcanic centres. In co-operation with international scientific partners (CNR-IGG of Pisa, Institut für Geologie und Mineralogie of Cologne, School of Earth Sciences of Melbourne) we performed multi-proxy geochemical analyses (XRF scanning for Si, K, Ca, Ti, Mn, Fe, Rb, Sr and Zr; total organic carbon, TOC; total inorganic carbon, TIC; total nitrogen and sulphur; oxygen and carbon stable isotopes) on a long core (87 m) retrieved from the Fucino basin in June 2015. On the basis of a tephrostratigraphic age-model developed at the CNR-IGAG in Rome the core span continuously between ca. 3000 and 160,000 yr. In this thesis we investigated an interval constrained between two Latium tephra layers corresponding to the 84.6 ± 5.1 and 36.2 ± 1.6 ka time-span. This period of time covers basically the ignition of the last glaciation (the transition between MIS5 and MIS4 in the marine isotope scale) and part of the last Pleniglacial period which was characterised by abrupt climatic and environmental changes on both global and regional scale. From time series of our proxy data we recognised complex low frequency trends with superposed higher frequency oscillations. We interpreted observed variations in terms of palaeohydrological and palaeoenvironmental changes in the lake catchment. On the basis of the most significative proxies (Ti, Ca, TOC%, TIC%, δ18O) we divided the record into three different periods: the first spanning between 85 and 68 ka, the second between 68 and 50 ka and the third between 50 and 36 ka. In our interpretation, the first period was characterised by low minerogenic input, high lake primary productivity and an enhanced precipitation. The second period had generalised high minerogenic input and low lake primary production, although it was mainly characterised by high-frequency and high- amplitude oscillations suggesting high frequency environmental instability. The beginning of the third period is marked by an abrupt increase in minerogenic input and by a prominent decrease in lake primary production. Overall, minerogenic input was high and lake productivity low. This period was mainly characterised by rather stable environmental conditions which were supported by less intense and abrupt variations in the hydrological regime. The last 2-3 ky of our record displayed a restoration of high-frequency and high-amplitude oscillations. By comparing our record with other regional (Monticchio Lake pollen record) and external (North Atlantic marine cores, Greenland ice cores) climatic archives and with Northern Hemisphere insolation curves we recognised a strong climatic coherence at a regional scale. We interpreted the 84,6-68 ka period as representative of late MIS5 interglacial conditions, the 68-50 ka period as representative of the onset of MIS4 fully glacial conditions and the 50-36 ka period as representative of MIS3 mild glacial conditions over the Western Mediterranean basin. Rapid oscillations in the hydrological regime over the lake catchment and in soil erosion rates can be regarded as the expression of Heinrich events and DO events, recognised in the North Atlantic, over the Mediterranean

    Effects of organic removal techniques prior to carbonate stable isotope analysis of lacustrine marls: a case study from palaeo‐lake Fucino (central Italy)

    Get PDF
    Rationale The suitability of organic matter (OM) removal pre‐treatments in isotopic studies of lacustrine carbonates is currently under debate. Naturally occurring OM seems to have a negligible effect on the bulk isotopic composition of carbonates compared with changes induced by pre‐treatments. This study provides further insights into the possible effects induced by commonly used pre‐treatments on natural lacustrine carbonates. Methods Sixteen samples from the Fucino F1–F3 lacustrine succession (Abruzzo, central Italy) were characterised for their mineralogical and geochemical composition and each was split into three identical aliquots. One aliquot was left untreated while the remaining two were treated with NaOCl and H2O2 dilutions. The same treatment was applied to an internal standard consisting of pure Carrara marble. The treated and untreated samples were analysed for their carbon (δ13C values) and oxygen (δ18O values) isotope compositions using an Analytical Precision AP2003 isotope ratio mass spectrometer. Results The samples had variable proportions of endogenic and detrital components, the detrital portion being more (less) abundant during colder (warmer) climate phases. We observed that neither the NaOCl nor the H2O2 treatment was able to completely remove OM and therefore there was selective removal of compounds within the OM pool. A possible effect of pre‐treatment is the loss of carbonates intimately interspersed within the OM, as suggested by the evolution of isotopic ratios towards the local detrital array. Conclusions Our study highlights sample‐specific changes in geochemistry associated with sample pre‐treatments; however, such changes do not seem to lead to either systematic and/or predictable isotopic shifts. We suggest that the suitability of NaOCl or H2O2 pre‐treatments for OM removal should be evaluated on a case‐by‐case basis. In the specific case of lacustrine marls from palaeo‐lake Fucino containing relatively low amounts of OM and in which both detrital and endogenic carbonates occur, both pre‐treatments should be avoided

    Fucino palaeo-lake: Towards the Palaeoenvironmental history of the last 430 Ka

    Get PDF
    © 2010 AIQUA - Associazione Italiana per lo Studio del Quaternario e EMMEVI - Servizio Congressi SPA. The sedimentary succession deposited in Fucino palaeo-lake potentially records the environmental history of the Central Mediterranean Region continuously since the early Pleistocene and up to recent historical times. Fucino palaeo-lake sediments are interbedded with numerous volcanic ash layers which allow the reconstruction a robust and independent chronological framework of past environment changes. This framework is a fundamental tool to synchronise different archives at a regional and extra-regional scale and to better understand the spatio-temporal climate variability in the Quaternary at the orbital and millennial-scales. Here we present new preliminary data for the last five glacial to interglacial cycles

    Neurogenic mechanisms in bladder and bowel ageing

    Get PDF
    The prevalence of both urinary and faecal incontinence, and also chronic constipation, increases with ageing and these conditions have a major impact on the quality of life of the elderly. Management of bladder and bowel dysfunction in the elderly is currently far from ideal and also carries a significant financial burden. Understanding how these changes occur is thus a major priority in biogerontology. The functions of the bladder and terminal bowel are regulated by complex neuronal networks. In particular neurons of the spinal cord and peripheral ganglia play a key role in regulating micturition and defaecation reflexes as well as promoting continence. In this review we discuss the evidence for ageing-induced neuronal dysfunction that might predispose to neurogenic forms of incontinence in the elderly

    Ricostruzione paleoambientale e paleoclimatica nella regione Mediterranea occidentale attraverso lo studio goechimico e mineralogico della successione sedimentaria del Lago Fucino (Avezzano, Abruzzo)

    No full text
    Questa tesi è volta alla realizzazione di registri paleoambientali per la regione mediterranea centrale che siano di alta risoluzione e di ampia significanza e che abbiano una cronologia indipendente. Conduciamo analisi geochimiche, isotopiche, mineralogiche e granulometriche sulle marne lacustri del paleolago Fucino (Avezzano, AQ, Abruzzo) recuperate durante due campagne di carotaggio scientifico (F1-F3 e F4-F5). Elaboriamo una cronologia basata su un quadro tefrostratigrafico di dettaglio che presenta datazioni 40Ar/39Ar e 14C (dati editi e inediti). La cronologia così elaborata indica che i registri ambientali F1-F3 e F4-F5 coprono rispettivamente, senza soluzione di continuità, gli ultimi due e gli ultimi cinque cicli glaciale-interglaciale. Elaboriamo dei dati per procura relativi a processi ambientali operanti a livello locale e regionale. Osserviamo notevoli variazioni ambientali su scale di tempo orbitali e sub-orbitali. Queste variazioni possono essere tracciate anche in altri archivi ambientali, sia lacustri, sia marini, sia speleotemici di tutta la regione mediterranea e nord-atlantica. Per mezzo di correlazioni tefrostratigrafiche e di allineamenti cronologici, elaboriamo una quadro paleoclimatico coerente a scala regionale individuando una complessa rete di relazioni tra processi ambientali dell’area mediterranea ed eventi climatici a scala emisferica ed interemisferica. Rileviamo un forte controllo dei parametri orbitali sulle passate variazioni climatiche. We study lacustrine sediments cored from the Fucino sedimentary succession (Abruzzo, Italy) during two separate drilling campaigns (F1-F3 and F4-F5). Sediments constitute of fine-grained carbonate marls with variable content of organic matter and are interbedded with several volcanic ash (tephra) layers. Lacustrine marls are studied by means of geochemical, isotopic, mineralogical and grain-size analyses. Tephra layers are used as stratigraphic and chronological markers and enable us to produce radiometrically-based chronologies for the F1-F3 and F4-F5 records. The F1-F3 record continuously spans over the last two glacial-interglacial cycles, while the F4-F5 record over the last five glacial-interglacial cycles. We combine our geological data into proxies for catchment- and regional-scale environmental processes. Our proxy time-series depicts prominent orbital and sub-orbital environmental changes that can be traced in other lacustrine, marine and speleothem records across the Mediterranean and North Atlantic regions. We produce spatially coherent palaeoclimatic reconstructions and recognise both synchronous and diachronous responses between different proxies and various proxy records

    Neolithic hydroclimatic change and water resources exploitation in the Fertile Crescent

    Get PDF
    Abstract In the first millennia of the Holocene, human communities in the Fertile Crescent experienced drastic cultural and technological transformations that modified social and human-environments interactions, ultimately leading to the rise of complex societies. The potential influence of climate on this “Neolithic Revolution” has long been debated. Here we present a speleothem record from the Kurdistan Region of Iraq, covering from Early Neolithic to Early Chalcolithic periods (~ 11 to 7.3 ka, 9000–5300 BCE). The record reveals the influence of the Siberian High on regional precipitation, and shows large hydroclimatic variability at the multicentennial scale. In particular, it highlights wetter conditions between 9.7 and 9.0 ka, followed by an abrupt reduction of precipitation between 9.0 and 8.5 ka, and a wetter interval between 8.5 and 8.0 ka. A comparison with regional and local archaeological data demonstrates an influence of recorded hydroclimatic changes on settlement patterns (size, distribution, permanent vs. seasonal occupation) and on the exploitation of water resources by Neolithic to Chalcolithic populations. Our record does not show prominent hydroclimatic changes at 9.3 and 8.2 ka, thus not supporting direct influence of such rapid and widespread events on the process of Neolithization and its cultural dispersal

    Central Mediterranean tephrochronology for the time interval 250–315 ka derived from the Fucino sediment succession

    No full text
    In the lacustrine succession F4‐F5 of the Fucino Basin, central Italy, 20 visible tephra layers were identified in the time interval 250–315 ka (Marine Isotope Stages 8–9). Fifteen of them contained suitable material to explore their volcanic sources. Among these tephra some well‐known eruptions and eruptive sequences of the Roman and Roccamonfina volcanoes were identified, such as the Tufo Giallo di Sacrofano and the Lower White Trachytic Tuff, respectively. Furthermore, the sediment succession documents a more complex eruptive history of the Sabatini, Vulsini, Colli Albani and Roccamonfina volcanic complexes during the investigated period, as inferred from previously undescribed tephra deposits. Single‐crystal‐fusion 40 Ar/ 39 Ar dating of two of the inspected tephra layers combined with two already published tephra ages provided the basis for a Bayesian age‐depth model. The modelled tephra ages allow chronological constraining of so‐far undefined eruptions of the Sabatini (272.5±4.7, 281.8±4.7, 308.5±2.8, 312.8±2.1 ka), the Vulsini (311.7±2.3, 311.9±2.3 ka) and the Colli Albani (301.0±3.6 ka) volcanic districts. Two tephra layers of an undefined volcanic source from the Roman volcanoes have modelled ages of 309.5±2.7 and 310.5±2.6 ka. The new 40 Ar/ 39 Ar and modelled ages were further used for a reassessment of the timing of already known and dated eruptive units, such as the Tufo Giallo di Sacrofano ( 40 Ar/ 39 Ar: 289.3±4.8 ka). Tephra tentatively correlated with the Valle Santa Maria, Case Pisello and the White Trachytic Tuff Unit E3 or Unit F offer modelled ages for these eruptions of 296.6±3.9, 301.8±3.5 and 303.6±3.4 ka, respectively. The results complete the tephrostratigraphical investigations of the c. 425 ka old F4‐F5 record, extend the Mediterranean tephrostratigraphical framework and provide a significant contribution for improving knowledge on Italian volcanic explosive activity

    Fucino palaeolake multiproxy data from F1-F3 core (Holocene - 190 ka)

    No full text
    Here we present a multi-proxy record from palaeolake Fucino (Abruzzo, Central Italy), acquired during the F1-F3 drilling campaign. This is the first continuous and high-resolution palaeoenvironmental record in the central Mediterranean region continuously spanning over the last two glacial-interglacial cycles and providing an independent chronology. The record consists of a core composite resulting from two parallel and adjacent core series (F1 and F3). Cores were analysed via high resolution XRF scanning and through geochemical, mineralogical and grain-size analyses on discrete samples. Selected XRF elemental counts (Ca, Ti and Zr), Total Nitrogen (TN), Total Organic and Inorganic Carbon (TOC, TIC), X-ray powder diffraction and grain-size data are used to develop proxies for local environmental processes strictly dependent on the hydro-climatic regime of the Central Mediterranean region. The chronology of the record is based on 17 radioisotopically dated tephra layers interbedded within the sedimentary succession. 14C and 40Ar/39Ar age points are interpolated with the bayesian age modelling package Bacon allowing a robust assessment of age uncertainties

    Central Mediterranean tephrochronology between 313 and 366 ka: New insights from the Fucino palaeolake sediment succession

    No full text
    Thirty‐two tephra layers were identified in the time‐interval 313–366 ka (Marine Isotope Stages 9–10) of the Quaternary lacustrine succession of the Fucino Basin, central Italy. Twenty‐seven of these tephra layers yielded suitable geochemical material to explore their volcanic origins. Investigations also included the acquisition of geochemical data of some relevant, chronologically compatible proximal units from Italian volcanoes. The record contains tephra from some well‐known eruptions and eruptive sequences of Roman and Roccamonfina volcanoes, such as the Magliano Romano Plinian Fall, the Orvieto–Bagnoregio Ignimbrite, the Lower White Trachytic Tuff and the Brown Leucitic Tuff. In addition, the record documents eruptions currently undescribed in proximal (i.e. near‐vent) sections, suggesting a more complex history of the major eruptions of the Colli Albani, Sabatini, Vulsini and Roccamonfina volcanoes between 313 and 366 ka. Six of the investigated tephra layers were directly dated by single‐crystal‐fusion 40Ar/39Ar dating, providing the basis for a Bayesian age–depth model and a reassessment of the chronologies for both already known and dated eruptive units and for so far undated eruptions. The results provide a significant contribution for improving knowledge on the peri‐Tyrrhenian explosive activity as well as for extending the Mediterranean tephrostratigraphical framework, which was previously based on limited proximal and distal archives for that time interval.Deutsche Forschungsgemeinschaft http://dx.doi.org/10.13039/501100001659Italian Ministry of Education, University and Researchhttps://doi.org/10.26022/IEDA/11232
    corecore