scholarly journals GPR Detection of Fossil Structures in Conductive Media Supported by FDTD Modelling and Attributes Analysis: An Example from Early Pleistocene Marine Clay at Bargiano Site (Central Italy)

Geosciences ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 386
Author(s):  
Maurizio Ercoli ◽  
Roberto Bizzarri ◽  
Angela Baldanza ◽  
Angela Bertinelli ◽  
Diego Mercantili ◽  
...  

The application of Ground Penetrating Radar (GPR) prospecting to the search of fossil structures, particularly using advanced techniques like Finite-difference time-domain (FDTD) modelling and GPR attribute analysis, is currently poorly exploited in paleontology. Here, we promote the use of such a GPR workflow at Bargiano (Umbria, central Italy), a unique paleontological site known for the discovery of cetacean skeletons, dolomitized sperm-whale cololites (Ambergrisichnu salleronae), and layered fossil assemblages. The study site is characterized by a very uneven topography shaping highly conductive clayey deposits, representing not exactly ideal conditions for GPR surveying. After generating models encompassing a real topography and variable electrical properties of media, we simulated buried fossil structures at variable depth with different size and geometry, using different operative frequencies. After obtaining information on the characteristics of reflections, investigation depth, and detectability, we provide a comparison with experimental data, also used to compute instantaneous amplitude and phase attributes. Upon depicting a peculiar GPR signature for our targets, we discuss the results in light of ground-truthing performed through trenching. Our workflow allowed us to restrict the excavation areas, extending the surface information in depth in a non-invasive way, and optimizing the field operations, necessary for the preservation of the study site.

2021 ◽  
Author(s):  
Brian J. Armstrong ◽  
Stephanie Edwards‐Baker ◽  
Paul Penzo‐Kajewski ◽  
Andy I. R. Herries

2014 ◽  
Vol 926-930 ◽  
pp. 2777-2780
Author(s):  
Hong Yuan Fang ◽  
Jian Li ◽  
Jia Li

The second-order Lobatto IIIA-IIIB symplectic partitioned RungeKutta (SPRK) method, combining with the first-order Mur absorbing boundary condition, is developed for the simulation of ground penetrating radar wave propagation in layered pavement structure. For 2-dimetional case, a significant advantage of this method is that only two functions need to be calculated at each time step. The total-field/scattered-field technique is used for plane wave excitation. Numerical examples are presented to verify the accuracy and efficiency of the proposed algorithm. The results illustrate that the reflected signal calculated by the SPRK method is in good agreement with that obtained using the finite difference time domain (FDTD) scheme, but the CPU time consumed by proposed algorithm is reduce about 20% of the FDTD scheme. In addition, an actual field test is conducted to evaluate the further performance of the SPRK method. It is found that the simulated waveform fits well with the measured signal in many aspects, especially in the peak amplitude and time delay.


2016 ◽  
Vol 17 (4) ◽  
pp. 362-370 ◽  
Author(s):  
Alexander Krainyukov ◽  
Igor Lyaksa

Abstract The paper is devoted to using ground penetrating radar (GPR) for the detection of tree roots in an urban area, since GPR allow detect the hidden objects in non invasive way. It is necessary exactly to know the growth direction, thickness and depth of the roots of the tree to confidently assert about the tree root influence on the technical condition of engineering objects and structures: of the buildings, of pavements, of roadway, of engineering communications and etc. The aim of the given research was experimentally to evaluation the possibilities of detection of tree roots in an urban area with the use of GPR on frequency 400 MHz and of algorithms of secondary processing of GPR signals. Results of interpretation of radar profile and evacuation of soil around tree show the possibility of detection of the tree roots and the determination of their parameters using one or two radar concentric profiles.


2014 ◽  
Vol 31 (2) ◽  
pp. 133-141 ◽  
Author(s):  
Fabian Welc ◽  
Radosław Mieszkowski ◽  
Sebastian Kowalczyk ◽  
Jerzy Trzciński

Abstract This paper presents the preliminary results of ground penetrating radar sounding applied at the desert archaeological site in Saqqara (Egypt). The survey was carried out in 2012 within a project realized by Institute of Archaeology, Cardinal Stefan Wyszyński University in Warsaw and the Faculty of Geology, University of Warsaw. One of the key aims of the research was testing the application of ground penetrating radar to non-invasive surveys of desert archaeological sites. Radargrams obtained for area of so called the Dry Moat channel surrounding the Step Pyramid complex have shown the geological structure of its filling. It comprises among others debris-sand conglomerate of diluval origin characterized by a significant content of the clay fraction and clay minerals. Such lithological content strongly attenuate the propagation of EM waves, restricting the depth range of the GPR survey. The conducted geophysical prospection west to the Step Pyramid in Saqqara has confirmed the high applicability of the GPR method in non-invasive studies of vast architectural structures, such as the monumental ditch surrounding the Step Pyramid known as the Dry Moat. It should summarised that high horizontal resolution obtained during GPR survey is a result of local geological structure of the searched area, i.e. strong lithological contrast of the sediments filling the Dry Moat, which, depending on their mineralogical composition


Author(s):  
Hamed Faghihi Kashani ◽  
Carlton L. Ho ◽  
Charles P. Oden ◽  
Stanley S. Smith

In recent years there has been an increase in the knowledge of, and need for, non-invasive monitoring of ballast in order to identify the problematic sections of track and decrease the maintenance cost. Various technologies such as Ground Penetrating Radar (GPR) are becoming accepted for investigating the condition of ballast. However since these techniques were not originally developed for engineering applications, their applicability in ballast evaluations can be sometimes uncertain. Continued empirical studies and condition specific calibrations are needed to demonstrate repeatable and quantifiable results. In this study large-scale track models with trapezoidal section area were constructed at the University of Massachusetts to investigate the effects of breakdown fouling, and the effects of changing geotechnical properties on GPR traces. This paper presents the design and construction of large scale track models, and methods used for GPR data collection. GPR data are presented in this paper that demonstrate sensitivity to the track model properties and variables. In particular, the experiments are being used to evaluate changes in GPR data with changing geotechnical properties of the ballast such as density, water content, grain size distribution (GSD), and fouling percentage.


Geosciences ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 416
Author(s):  
Angela Baldanza ◽  
Roberto Bizzarri ◽  
Francesco Posati ◽  
Manuel Ravoni

Although drillholes in modern and ancient ostracods are known, the record is relatively scarce when compared to other taxa, and mainly exist with reference to the marine environment. Moreover, less is known about perforated ostracods, and more generally, about bioerosion in freshwater environments. Traces of predation on freshwater ostracods are reported for the first time in deep-lake deposits belonging to the early Pleistocene Fosso Bianco Unit, and outcropping in the Cava Nuova section (Umbria, central Italy). Deposits are mainly clay to silty clay and sand; the fossil record is sparse, and is mainly comprised of very rare gastropods and bivalves, ostracods and plant remains (leaves, seeds and wood’s fragments). The association of ostracods consists of Candona (Neglecandona) neglecta, Caspiocypris basilicii, Caspiocypris tiberina, Caspiocypris perusia, Caspiocypris tuderis, Caspiocypris posteroacuta, and Cyprideis torosa. The Caspiocypris group, considered to be endemic to the grey clays of the Fosso Bianco Unit, present the majority of specimens affected by predation, with a prevalence of predated female valves and a comparable number of right and left predated valves, while only a few of Candona(N.) neglecta (adult and juvenile) valves are perforated. Traces of predation for nourishment, represented by microborings of different types, were abscribed to the ichnospecies Oichnus paraboloides Bromley 1981, Oichnus simplex Bromley 1981, Oichnus gradatus Nielsen and Nielsen 2001, Oichnus ovalis Bromley 1993, and Dipatulichnus rotundus Nielsen and Nielsen 2001. Microboring affected both adult and juvenile specimens, evidencing prey–predator coexistence in the same environment over a long period of time. This report makes a fundamental contribution to the knowledge of predation in this peculiar confined environment, also suggesting prey–predator relations over a relatively short time interval (80–160 ka).


2016 ◽  
Vol 3 (1) ◽  
pp. 66
Author(s):  
Giovanni Pasini ◽  
Alessandro Garassino

We report <em>Petrochirus</em> sp. (Diogenidae Ortmann, 1892) from the early Pleistocene of the Podere dell’Infrascato, Volterra (Pisa, Tuscany, central Italy). The record of <em>Petrochirus</em> sp. in this peculiar environment (upper bathyal zone) is significant due to the scarce knowledge about the genus distribution in the paleo-Mediterranean area.


Author(s):  
Alessio Iannucci ◽  
Marco Cherin ◽  
Leonardo Sorbelli ◽  
Raffaele Sardella

Abstract The Miocene-Pliocene (Turolian-Ruscinian) transition represents a fundamental interval in the evolution of Euro-Mediterranean paleocommunities. In fact, the paleoenvironmental changes connected with the end of the Messinian salinity crisis are reflected by a major renewal in mammal faunal assemblages. An important bioevent among terrestrial large mammals is the dispersal of the genus Sus, which replaced all other suid species during the Pliocene. Despite its possible paleoecological and biochronological relevance, correlations based on this bioevent are undermined by the supposed persistence of the late surviving late Miocene Propotamochoerus provincialis. However, a recent revision of the type material of this species revealed an admixture with remains of Sus strozzii, an early Pleistocene (Middle Villafranchian to Epivillafranchian) suid, questioning both the diagnosis and chronological range of P. provincialis. Here we review the late Miocene Suidae sample recovered from the Casino Basin (Tuscany, central Italy), whose taxonomic attribution has been controversial over the nearly 150 years since its discovery. Following a comparison with other Miocene, Pliocene, and Pleistocene Eurasian species, the Casino Suidae are assigned to P. provincialis and the species diagnosis is emended. Moreover, it is recognized that all the late Miocene (Turolian) European Propotamochoerus material belongs to P. provincialis and that there is no compelling evidence of the occurrence of this species beyond the Turolian-Ruscinian transition (MN13-MN14).


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