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    Electrical resistivity and Ground Penetrating Radar for the characterisation of the internal architecture of Quaternary sediments in the Midlands of Ireland


    Pellicer, Xavier M. and Gibson, Paul (2011) Electrical resistivity and Ground Penetrating Radar for the characterisation of the internal architecture of Quaternary sediments in the Midlands of Ireland. Journal of Applied Geophysics, 75. pp. 638-647. ISSN 0926-9851

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    Abstract

    Geophysical techniques Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) supported by traditional field methods are used for the geological mapping, description and interpretation of Quaternary unconsolidated sediments in a site located in theMidlands of Ireland. The site comprises a broad range of glacial and postglacial sediments (diamicton, esker sand and gravel, glaciolacustrine sand, glaciolacustrine silt/clay and peat). Preliminary fieldwork comprising, geomorphological mapping, lithostratigraphic analysis of exposures and borehole drilling and laboratory testing encompassing particle size distribution analysis were carried out to broadly characterise the geology of the study area. These data aided locating the geophysical profiles and supported the geophysical data interpretation. FiveGPR radargrams were collected and permitted depicting the subsurface internal architecture within low conductivity unconsolidated sediments and aided to the classification and characterisation of sedimentological and deformational structures. Four ERT profiles allowed the depth to bedrock to be determined and lithological classification of the sediments. The use of these geophysical techniques in combination with geotechnical and geological data allowed (i) the determination of the lithological composition and detailed internal architecture of the subsurface, (ii) the characterisation and description of the geology of the site and (iii) understanding the depositional processes acting in the area during ice withdrawal. Diamicton and esker gravelswere deposited subglacially by an ice sheetwithdrawingwestwards; glaciolacustrine sediments located along the southmargin of the esker ridgewere laid down in an ice marginal environment as a subaqueous fan composed of silt, sand and gravel, and as distal deposits composed of silt and clay in the lower ground area between the fan and the esker ridge. Peat developed during postglacial times andwas partially cut away by anthropogenic action at a later stage.

    Item Type: Article
    Keywords: Glacial; Electrical Resistivity Tomography; GPR; Near-surface; Ireland;
    Academic Unit: Faculty of Social Sciences > Geography
    Item ID: 4191
    Depositing User: Paul Gibson
    Date Deposited: 06 Feb 2013 10:47
    Journal or Publication Title: Journal of Applied Geophysics
    Publisher: Elsevier
    Refereed: Yes
    URI:

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