401 research outputs found

    Insight Into Provenance and Variability of Atmospheric Dust in Antarctic Ice Cores During the Late Pleistocene From Magnetic Measurements

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    We measured saturation isothermal remanent magnetization (SIRM), coercivity of remanence (Hcr), and insoluble dust mass concentration (IDC) of 49 ice samples from Vostok and EPICA Dome-C ice cores (Antarctica) as a measure of magnetic properties of the aerosol dust trapped in the ice. Samples range in age from marine isotopic stage (MIS) 7 to 19 in EPICA Dome-C ice core and from MIS 1 to 11 in Vostok ice core. Data from ice samples were compared with 86 samples from possible source areas (PSA) from East Antarctica, including 11 samples from South America and New Zealand. Previous results from MIS 1 to MIS 6 found that magnetic properties of aerosol dust could be divided in two distinct groups characterized by high-Hcr and low-SIRMdust for glacial samples, and low-Hcr and high-SIRMdust, for interglacial samples. The new data from older ice samples highlighted several discrepancies from this expectation with significant differences between Vostok and Dome-C sites. Magnetic properties of Antarctic PSA sample show a large variability, however, PSA samples from Victoria Land and few other, have magnetic properties compatible with that of the glacial dust, or more precisely with samples characterized by high dust flux. The new data from Pleistocene ice and from PSA samples confirm South American and Antarctic provenance of the largest atmospheric dust load typical of glacial stages. On the other hand, we did not found any PSA sample with properties compatible with the highly magnetic samples (mostly from interglacial stages), which are characterized by low IDC. These samples from the oldest and deepest part of the cores revealed a more complex picture than previously outlined from the analysis of MIS 1–6, and show unusual magnetic properties which can be tentatively attributed to post-depositional alteration occurring into the ice

    Geoarchaeology as a tool for reconstructing the evolution of the Apuo-Versilian Plain (NW Italy)

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    A geoarchaeological approach integrating geomorphological, stratigraphical and archaeologic data was adopted to reconstruct the palaeogeographic evolution of an area of the Apuo-Versilian plain since the Etruscan age. We produced a geomorphological map, analyzed stratigraphy data from sections/boreholes in the plain, and compiled a dataset of archaeological findings with a particular focus on the Acquarella site which is an outstanding settlement in the area. The plotting of the archaeological findings on the geomorphological map allowed to better constraint the landforms surveyed by field work and remote sensing analyses. The analyzed stratigraphic data suggests a discontinuous trend of coastal progradation. Oscillations in this trend are testified by four small scale transgressive - regressive parasequences that occurred after 4600 yrs cal B.C.. In agreement with the archaeological findings on the surface, the base of the uppermost sequence was dated to ca 500 cal AD, implying that since the Early Middles Ages the progradation trend has been continuous. Furthermore, a pronounced increase in progradation was observed after the 16th century, probably linked to both climatic influence (Little Ice Age) and human impacts (deforestation). The Acquarella rustic building has developed in this coastal-piedmont context since the Etruscan age. The reason for its longevity (eh century B.C. - Early Middle Ages) was related to a suite of environmental aspects such as the protection offered by the surrounding hills, water availability, and the elevation above a coastal plain experiencing periodic flooding Moreover, a crucial element was identified in the position of the site in respect to the main ancient roads connecting Pisa to Luni (Via Aurelia/Aemilia) and the coastal area with the inland. The correlation of the geomorphology with the archeological data from Acquarella, along with the other findings along the coastal-piedmont area allowed to depict the landscape scenarios relative to the Etruscan, Roman, Early Middle ages and Modern ages

    A long-term chronology of Pinus pinea L. from Parco della Versiliana (Pietrasanta, Italy) derived from treefall induced by a windstorm on March 4th-5th, 2015

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    Abstract Pinewoods are distinctive environmental elements in the Mediterranean coastal area and have both natural and historical significance. From the evening of March 4th to the morning of March 5th, 2015, a severe and unusual windstorm occurred in the Tuscany region of central Italy with wind gusts over 120 km/h. The windstorm caused vast damage to the anthropic and natural environment and wounded numerous trees in the renowned pinewoods of Parco della Versiliana in the Tyrrhenian coastal area. The meteorological calamity provided the opportunity to i) date the onset of the artificial plantation of the present Italian stone pine (Pinus pinea L.) forest to the 1820s, ii) build a long-term tree-ring chronology of the Italian stone pines in the area and iii) analyze the climate-growth relationship of the Italian stone pine in the study area. The resulting Versiliana chronology was derived from 60 trees and spanned from 1828 to 2014 (187 years), representing one of the longest living Italian stone pine forests on the Italian Peninsula. Finally, the climate-growth analysis highlighted that at this site the latewood width is positively influenced by summer temperature, a peculiarity worthy of further investigations

    The Most Extensive Holocene Advance in the Stauning Alper, East Greenland, Occurred in the Little Ice Age

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    We present glacial geologic and chronologic data concerning the Holocene ice extent in the Stauning Alper of East Greenland. The retreat of ice from the late-glacial position back into the mountains was accomplished by at least 11 000 cal years B.P. The only recorded advance after this time occurred during the past few centuries (the Little Ice Age). Therefore, we postulate that the Little Ice Age event represents the maximum Holocene ice extent in this part of East Greenland

    NDVI Analysis for Monitoring Land-Cover Evolution on Selected Deglaciated Areas in the Gran Paradiso Group (Italian Western Alps)

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    The ongoing climate warming is affecting high-elevation areas, reducing the extent and the duration of glacier and snow covers, driving a widespread greening effect on the Alpine region. The impact assessment requires therefore the integration of the geomorphological context with altitudinal and ecological features of the study areas. The proposed approach introduces chronologically-constrained zones as geomorphological evidence for selecting deglaciated areas in the alpine and non-alpine belts. In the present study, the protected and low-anthropic-impacted areas of the Gran Paradiso Group (Italian Western Alps) were analysed using Landsat NDVI time series (1984–2022 CE). The obtained results highlighted a progressive greening even at a higher altitude, albeit not ubiquitous. The detected NDVI trends showed, moreover, how the local factors trigger the greening in low-elevation areas. Spectral reflectance showed a general decrease over time, evidencing the progressive colonisation of recently deglaciated surfaces. The results improved the discrimination between different greening rates in the deglaciated areas of the Alpine regions. The geomorphological-driven approach showed significant potential to support the comprehension of these processes, especially for fast-changing areas such as the high mountain regions

    Chemical and Lead Isotope characterisation of First World War shrapnel balls and bullets used on the Alpine Austrian\u2013Italian Front

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    Chemical and lead isotope characterisation was carried out on shrapnel balls and bullets dating back to the First World War (WWI). These ammunitions were widely utilised in the Alpine Austrian\u2013Italian front located in the Italian Alps. The investigation has been performed using inductively coupled plasma quadrupole mass spectrometry equipped with an octopole reaction system (ORS-ICP-QMS). The main goal of this work was to identify the elemental and lead isotope composition of raw materials and to discriminate between the military objects analysed. The results of multi-elemental analysis indicate that the shrapnel ball samples consisted of soft Pb or hard Pb with Sb depending on the use, the weapon type and the specific nation. The Italian shrapnel balls were made from hard Pb, as opposed to those of the Austrian\u2013 Hungarian samples. Through the investigation of lead isotope ratios, it has been possible to differentiate most of the Italian shrapnel balls from those of Austrian\u2013 Hungarian origin. Furthermore, some Italian shrapnel balls had a different lead isotope composition depending on their calibre. The elemental composition and lead isotopic signature of bullets show a clear discrimination between the external jacket and the core in relation to projectile type and nationality. The bullet cores consist of 164 Scientia Militaria, South African Journal of Military Studies, Vol 46, Nr 1, 2018. doi: 10.5787/46-1-1230 Pb\u2013Sb alloy regardless of the region of origin. This work allowed us to investigate the potential applications of trace elements and lead isotope analyses to discriminate military artefacts of different origin

    Chemical and lead isotope characterisation of First World War shrapnel balls and bullets used on the Alpine Austrian–Italian Front

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    Chemical and lead isotope characterisation was carried out on shrapnel balls and bullets dating back to the First World War (WWI). These ammunitions were widely utilised in the Alpine Austrian–Italian front located in the Italian Alps. The investigation has been performed using inductively coupled plasma quadrupole mass spectrometry equipped with an octopole reaction system (ORS-ICP-QMS). The main goal of this work was to identify the elemental and lead isotope composition of raw materials and to discriminate between the military objects analysed. The results of multi-elemental analysis indicate that the shrapnel ball samples consisted of soft Pb or hard Pb with Sb depending on the use, the weapon type and the specific nation. The Italian shrapnel balls were made from hard Pb, as opposed to those of the Austrian– Hungarian samples. Through the investigation of lead isotope ratios, it has been possible to differentiate most of the Italian shrapnel balls from those of Austrian– Hungarian origin. Furthermore, some Italian shrapnel balls had a different lead isotope composition depending on their calibre. The elemental composition and lead isotopic signature of bullets show a clear discrimination between the external jacket and the core in relation to projectile type and nationality. The bullet cores consist of  Pb–Sb alloy regardless of the region of origin. This work allowed us to investigate the potential applications of trace elements and lead isotope analyses to discriminate military artefacts of different origins.Keywords: ICP-MS, trace element, source identification, principal component analysis, forensic scienc

    Phenotypical heterogeneity linked to adipose tissue dysfunction in patients with type 2 diabetes

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    Adipose tissue (AT) inflammation leads to increased free fatty acid (FFA) efflux and ectopic fat deposition, but whether AT dysfunction drives selective fat accumulation in specific sites remains unknown. The aim of the present study was to investigate the correlation between AT dysfunction, hepatic/pancreatic fat fraction (HFF, PFF) and the associated metabolic phenotype in patients with Type 2 diabetes (T2D). Sixty-five consecutive T2D patients were recruited at the Diabetes Centre of Sapienza University, Rome, Italy. The study population underwent clinical examination and blood sampling for routine biochemistry and calculation of insulin secretion [homoeostasis model assessment of insulin secretion (HOMA-β%)] and insulin-resistance [homoeostasis model assessment of insulin resistance (HOMA-IR) and adipose tissue insulin resistance (ADIPO-IR)] indexes. Subcutaneous (SAT) and visceral (VAT) AT area, HFF and PFF were determined by magnetic resonance. Some 55.4% of T2D patients had non-alcoholic fatty liver disease (NAFLD); they were significantly younger and more insulin-resistant than non-NAFLD subjects. ADIPO-IR was the main determinant of HFF independently of age, sex, HOMA-IR, VAT, SAT and predicted severe NAFLD with the area under the receiver operating characteristic curve (AUROC)=0.796 (95% confidence interval: 0.65-0.94, P=0.001). PFF was independently associated with increased total adiposity but did not correlate with AT dysfunction, insulin resistance and secretion or NAFLD. The ADIPO-IR index was capable of predicting NAFLD independently of all confounders, whereas it did not seem to be related to intrapancreatic fat deposition; unlike HFF, higher PFF was not associated with relevant alterations in the metabolic profile. In conclusion, the presence and severity of AT dysfunction may drive ectopic fat accumulation towards specific targets, such as VAT and liver, therefore evaluation of AT dysfunction may contribute to the identification of different risk profiles among T2D patients

    Pinus cembra L. tree-ring data as a proxy for summer mass-balance variability of the Careser Glacier (Italian Rhaetian Alps)

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    Glacial extent and mass-balance are sensitive climate proxies providing solid information on past climatic conditions. However, series of annual mass balance measurements of more than sixty years are scarce. To our knowledge, this is the first time the latewood density data (MXD) of the Swiss stone pine (Pinus cembra L.) has been used to reconstruct the summer mass balance (Bs) of an Alpine glacier. The MXD-based Bs well correlates with a Bs reconstruction based on the May to September temperature. Winter precipitation has been used as independent proxy to infer the winter mass balance and to obtain an annual mass balance (Bn) estimate dating back to the glaciological year 1811/12. The reconstructed MXD/precipitation-based Bn well correlates with the data both of the Careser and of other Alpine glaciers measured by the glaciological method. A number of critical issues should be considered in both proxies including nonlinear response of glacial mass balance to temperature, bedrock topography, ice thinning and fragmentation, MXD acquisition and standardization methods, and finally the “divergence problem” responsible for the recent reduced dendroglaciological reconstructions using this stable and reliable proxy

    Surface exposure ages imply multiple low-amplitude Pleistocene variations in East Antarctic Ice Sheet, Ricker Hills, Victoria Land

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    One of the major issues in (palaeo-) climatology is the response of Antarctic ice sheets to global climate changes. Antarctic ice volume has varied in the past but the extent and timing of these fluctuations are not well known. In this study, we address the question of amplitude and timing of past Antarctic ice level changes by surface exposure dating using in situ produced cosmogenic nuclides (10Be and 21Ne). The study area lies in the Ricker Hills, a nunatak at the boundary of the East Antarctic Ice Sheet in southern Victoria Land. By determining exposure ages of erratic boulders from glacial drifts we directly date East Antarctic Ice Sheet variations. Erosion-corrected neon and beryllium exposure ages indicate that a major ice advance reaching elevations of about 500m above present ice levels occurred between 1.125 and 1.375 million years before present. Subsequent ice fluctuations were of lesser extent but timing is difficult as all erratic boulders from related deposits show complex exposure histories. Sample-specific erosion rates were on the order of 20-45cmMa-1 for a quartzite and 10-65cmMa-1 for a sandstone boulder and imply that the modern cold, arid climate has persisted since at least the early Pleistocen
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