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  • Articles  (2)
  • 02.01. Permafrost  (1)
  • Central Italy; Limnology; Paleolimnology; Paleoseismicity; Paleomagnetism; Stable isotopes; Scanning XRF  (1)
  • 1
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    Lakes as paleoseismic records in a seismically-active, low-relief area (Rieti Basin, central Italy) (2019)
    Details
    Publication Date: 2019-10-16
    Description: Small lakes in low relief areas are atypical candidates for studies on paleoseismicity, but their sediments can contain seismically induced event layers (seismites) generated through strong ground shaking, sediment transport, hydrological reorganization and/or changes in groundwater chemistry and flow. Lakes Lungo and Ripasottile are shallow lakes (〈10 m deep) located in the tectonically active Rieti Basin in the central Apennines, Italy, where strong normal faulting earthquakes (Mw 6.5 to 7.0) regularly occur. Sediment cores from these lakes provide paleoseismic indicators for the past similar to 1000 years. Sedimento-logical and geochemical analysis reveals four event layers identified in both lakes that correspond with documented large-scale earthquakes in 1298, 1349, 1639, and 1703 AD. Chronological correlation between earthquakes and paleoseismic features is reliable because of the resolution of sediment dating available for the studied cores. The common physical structure is a physically homogenous bed (homogenite) of re-suspended sediment consisting of a denser, high magnetic susceptibility (kappa) clastic base, with organic matter concentrated above. Co-seismic to post-seismic chemical signatures are associated with some event layers and may represent abrupt or transient shifts to a groundwater-dominated system, or permanent changes in groundwater flow and/or spring discharge. Excursions in delta C-13(org) may represent disruptions or changes in carbon source. Not all event layers show the same features, a result attributed to differences in seismic processes as well as the lake attributes, and anthropogenic modification. The observations made here may provide a new means of detecting paleoseismicity and may be applied to other low relief lakes in seismically active areas. (C) 2019 Elsevier Ltd. All rights reserved.
    Description: Published
    Description: 186-207
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: 4A. Oceanografia e clima
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Keywords: Central Italy; Limnology; Paleolimnology; Paleoseismicity; Paleomagnetism; Stable isotopes; Scanning XRF
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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  • 2
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    Antarctic permafrost degassing in Taylor Valley by extensive soil gas investigation (2023)
    Elsevier
    Details
    Publication Date: 2023-02-20
    Description: Ongoing studies conducted in northern polar regions reveal that permafrost stability plays a key role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emissions, both from physical and microbial processes. The potential impact of greenhouse gas release from the Antarctic region has not, to date, been investigated. In Antarctica, the McMurdo Dry Valleys comprise 10 % of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit at a slower rate. The work presented herein examines a comprehensive sample suite of soil gas (e.g., CO2, CH4 and He) concentrations and CO2 flux measurements conducted in Taylor Valley during austral summer 2019/2020. Analytical results reveal the presence of significant concentrations of CO2, CH4 and He (up to 3.44 vol%, 18,447 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increased CO2 flux rates (estimated CO2 emissions in the study area of 21.6 km2 ≈ 15 tons day-1). We suggest that the gas source is connected with the deep brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emissions from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms.
    Description: Published
    Description: 161345
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Antarctica; ; CO(2) output; ; McMurdo Dry Valleys; ; Permafrost; ; Soil gas survey ; 02.01. Permafrost
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Location Call Number Limitation Availability
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