Combining sedimentological and geophysical data for high-resolution 3-D mapping of fluvial architectural elements in the Quaternary Po plain (Italy)

Bersezio, R.; Giudici, M.; Mele, M.

doi:10.1016/j.sedgeo.2007.05.002

Cited by 80 publications

(54 citation statements)

References 22 publications

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“…According to Lunt et al (2004), describing deposits in three dimensions below the water table and studying depositional processes during the all-important high-flow stages and over large time and space scales are the most important challenges. According to Bersezio et al (2007), the models based on the borehole data are often oversimplified. Lunt et al (2004) reported that most of the direct observations of river deposits come from trenches and cut-bank exposures situated above the water table, which represent a small fraction of channel-belt deposits.…”

mentioning

confidence: 99%

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Słowik

2011

J Soils Sediments

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Purpose The main goal of the study was to compare the potential of conventional and geophysical methods (ground-penetrating radar; GPR) to reconstruct the migration phases of a meandering lowland riverbed: the Obra River in western Poland. The purpose was to verify that the migration phases can be distinguished using the GPR measurement providing near-continuous imaging of alluvial structures and to discuss differences between the spatial extent of the migration phases distinguished using geologic data and GPR surveys. Materials and methods Historical maps from the eighteenth and the nineteenth century were analyzed to study transformations of the Obra River bed pattern. One hundred twenty tube sample borings were undertaken along five profiles to recognize the floodplain lithology. Granulation coefficients were determined using the method of moments to distinguish lithofacies of the alluvial deposits. The GPR measurement was performed using a georadar MALA ProEx equipped with shielded 100 and 250 MHz antennae. The GPR images were compared to geologic profiles to determine the depth scale and accuracy of the measurements. The depth scale of the GPR images was determined on the basis of the correlation of the radar reflections with the geologic profiles. Ten organic sediment samples were collected to determine the age of the migration phases.Results and discussion Point bars with layering of sand deposits, organic sediment fills, erosion surfaces, and gravel beds were distinguished using the 250 MHz antenna. However, some of sedimentary structures (e.g., inserts of fine sands in the organic deposits) were beyond the detection range of the antennae. The glacial/alluvial sediment interface was detected using the 100 MHz antenna which enabled the determination of the thickness of the alluvial fill. Traces of a period of early development of the Obra valley and three migration phases of the Obra River bed were distinguished. The research indicated that the Obra was a meandering river at least 7,000 years before present and that during the last 3,000 years, channel islands were formed within the studied section of the valley. Conclusions The GPR method allowed for the analysis of the spatial variability of alluvial deposits and helped to describe how meander bends were formed. The presented GPR images illustrate the spatial extent of the migration phases in a more detailed way than using only sedimentary information. However, geologic data are necessary for interpretation of the GPR images. It was shown that the GPR method gives useful results in spite of rough land surface and dense vegetation.

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Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Słowik

2011

J Soils Sediments

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“…Recent advances in affordable geophysical techniques for regional surveying are expected to greatly aid in delineating the physical characteristics of aquifers (see, e.g. Bersezio et al 2007;Chalikakis et al 2008).…”

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Geochemical reactivity of subsurface sediments as potential buffer to anthropogenic inputs: a strategy for regional characterization in the Netherlands

Gaans

Griffioen

Mol³

et al. 2010

J Soils Sediments

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Purpose Sedimentary aquifers are prone to anthropogenic disturbance. Measures aimed at mitigation or adaptation require sound information on the reactivity of soil/sediments towards the infiltrating water, as this determines the chemical quality of the groundwater and receiving surface waters. Here, we address the issues of relevant sediment properties, adequate analytical methods, borehole location selection, detail of stratification, and required sample size, to develop a protocol for efficient characterization of subsurface reactivity on a regional scale. Materials and methods The sequence of geological formations in the Dutch part of the North Sea Basin is documented in the form of systematic descriptions of some 450,000 borings. The basic data are stored in a database that also includes a limited amount of geochemical data collected for specific research projects. Based on the borehole descriptions, a Digital Geological Model of the Netherlands (DGM) has recently been completed. We combined the results of a statistical analysis of the existing geochemical data with theoretical and practical considerations, to assess the degree of variability of subsurface reactivity, the relevance of different DGM-based stratifications, and the efficiency and possible redundancy of analytical parameters. Results and discussion We present two protocols for the quantitative characterization of the reactive properties of the soil and subsurface sediments of the Netherlands, down to a depth of about 30 m below surface level. As numerous strategies are already available for soil surveying, the facies-based protocol for boring and sampling is aimed at subsoil sediments. Stratification is a combination of regional, lithological, and lithostratigraphical classifications. Selection of borehole locations and sampling depths is first based on the a priori information. Given the results of the first round, additional boring, sampling and analysis are performed when necessary. The analytical protocol also applies to soil surveys. It deploys limited means to obtain the most relevant information on subsurface reactivity in view of the priority environmental issues identified. Conclusions With the progress of technologies for aquifer architecture characterization and routine chemical analysis, assessment of subsurface reactivity on a regional scale has now become feasible. Lithological stratification is essential, but regional and lithostratigraphical variability cannot be ignored. With adequate stratification, a sample size of 45 per stratum was found sufficient in most instances. The key analytes chosen appear to be statistically independent; hence, a further reduction in analytical techniques would result in serious loss of information.

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“…In contrast, the low frequency decreases the resolution, and the survey depth is deeper [16]. GPR has been used to analyze fluvial facies [15,[17][18][19][20][21][22][23]. However, silt and clay depositions cause attenuation of the radar signal which limits the depth range of measurement but can also be useful to determine the thickness of alluvial fill [24].…”

Section: Ground Penetrating Radar (Gpr)mentioning

confidence: 99%

Imaging and locating paleo-channels using geophysical data from meandering system of the Mun River, Khorat Plateau, Northeastern Thailand

et al. 2017

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Abstract:The Khorat Plateau from northeast Thailand, the upstream part of the Mun River flows through clastic sedimentary rocks. A massive amount of sand was transported. We aimed to understand the evolution of fluvial system and to discuss the advantages of two shallow geophysical methods for describing subsurface morphology of modern and paleo-channels. We applied Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) to characterize the lateral, vertical morphological and sedimentary structures of paleo-channels, floodplain and recent point bars. Both methods were interpreted together with on-sites boreholes to describe the physical properties of subsurface sediments. As a result, we concluded that four radar reflection patterns including reflection free, shingled, inclined and hummocky reflections were appropriated to apply as criteria to characterize lateral accretion, the meandering rivers with channel-filled sequence and floodplain were detected from ERT profiles. The changes in resistivity correspond well with differences in particle size and show relationship with ERT lithological classes. Clay, silt, sand, loam and bedrock were classified by the resistivity data. Geometry of paleo-channel embayment and lithological differences can be detected by ERT, whereas GPR provides detail subsurface facies for describing point bar sand deposit better than ERT.

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Combining sedimentological and geophysical data for high-resolution 3-D mapping of fluvial architectural elements in the Quaternary Po plain (Italy)

Cited by 80 publications

References 22 publications

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Reconstructing migration phases of meandering channels by means of ground-penetrating radar (GPR): the case of the Obra River, Poland

Geochemical reactivity of subsurface sediments as potential buffer to anthropogenic inputs: a strategy for regional characterization in the Netherlands

Imaging and locating paleo-channels using geophysical data from meandering system of the Mun River, Khorat Plateau, Northeastern Thailand

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