scholarly journals Ground-Penetrating Radar Prospections to Image the Inner Structure of Coastal Dunes at Sites Characterized by Erosion and Accretion (Northern Tuscany, Italy)

2021 ◽  
Vol 11 (23) ◽  
pp. 11260
Author(s):  
Adriano Ribolini ◽  
Duccio Bertoni ◽  
Monica Bini ◽  
Giovanni Sarti
Keyword(s):  
Ground Penetrating Radar ◽  
Coastal Dunes ◽  
General Context ◽  
Depositional Processes ◽  
Sedimentary Architecture ◽  
Formation And Evolution ◽  
Run Up ◽  
Ground Penetrating ◽  
Radar Facies ◽  
Sedimentary Budget

In this study we aimed to gain insights into dune formation and evolution from select coastal tracts of Northern Tuscany by inspecting their internal sedimentary architecture with Ground-Penetrating Radar (GPR) analysis. Erosion, equilibrium and accretion characterize the selected coastal tracts, and this analysis remarks on some GPR features consistently associated with specific coastal evolution states. A standard sequence of data processing made it possible to trace several radar surfaces and reflectors in the GPR profile, eventually interpreted in terms of depositional processes and erosive events. The stable or currently accreting coastal sectors show radar features compatible with a general beach progradation process, punctuated by berm formation in the general context of a positive sedimentary budget. Additionally, the radar facies distribution locally supports a mechanism of dune nucleation on an abandoned berm. Conversely, the GPR profile of the coastal sector today affected by erosion shows how a negative sedimentary budget inhibited coastal progradation and favored destructive events. These events interacted also with the active dunes, as demonstrated by the overlapping of wave run-up and aeolian radar facies. GPR prospections were effective at delineating the recent/ongoing coastal sedimentary budget by identifying radar features linked to construction/destruction phenomena in the backshore, and to dune nucleation/evolution.

scholarly journals Ground Penetrating Radar investigation of depositional architecture: the São Sebastião and Marizal formations in the Cretaceous Tucano Basin (Northeastern Brazil)

2016 ◽  
Vol 46 (1) ◽  
pp. 15-27 ◽  
Author(s):  
Larissa Natsumi Tamura ◽  
Renato Paes de Almeida ◽  
Fabio Taioli ◽  
André Marconato ◽  
Liliane Janikian
Keyword(s):  
Ground Penetrating Radar ◽  
Sedimentary Environment ◽  
Geophysical Methods ◽  
Radar Data ◽  
Northeastern Brazil ◽  
Sedimentary Environments ◽  
Hydrocarbon Reservoir ◽  
Depositional Architecture ◽  
Ground Penetrating ◽  
Radar Facies

ABSTRACT: One key factor for the advance in the study of fluvial deposits is the application of geophysical methods, being the Ground Penetrating Radar one of special value. Although applied to active rivers, the method is not extensively tested on the rock record, bearing interest for hydrocarbon reservoir analogue models. The São Sebastião and Marizal formations were the subject of previous studies, which made possible the comparison of Ground Penetrating Radar survey to previous stratigraphic studies in order to identify the best combination of resolution, penetration and antenna frequency for the studied subject. Eight radar facies were identified, being six of them related to fluvial sedimentary environments, one related to eolian sedimentary environment and one radar facies interpreted as coastal sedimentary environment. The Ground Penetrating Radar data showed compatibility to sedimentary structures in the outcrops, like planar and trough cross-stratified beds. It is noted that the obtained resolution was efficient in the identification of structures up to 0.3 m using a 100 MHz antenna. In this way, the Ground Penetrating Radar survey in outcrops bears great potential for further works on fluvial depositional architecture.

A comparison of the correlation structure in GPR images of deltaic and barrier‐spit depositional environments

Geophysics ◽  
2000 ◽  
Vol 65 (4) ◽  
pp. 1142-1153 ◽  
Author(s):  
Paulette Tercier ◽  
Rosemary Knight ◽  
Harry Jol
Keyword(s):  
Correlation Length ◽  
Ground Penetrating Radar ◽  
Depositional Environments ◽  
Geostatistical Analysis ◽  
Maximum Correlation ◽  
Correlation Lengths ◽  
Correlation Structures ◽  
Geostatistical Models ◽  
Ground Penetrating ◽  
Radar Facies

We have used geostatistical analysis of radar reflections to quantify the correlation structures found in 2-D ground‐penetrating radar (GPR) images. We find that the experimental semivariogram, the product of the geostatistical analysis of the GPR data, is well‐defined and can be modeled using standard geostatistical models to obtain an estimate of the range or correlation length, and the maximum correlation direction, in the 2-D GPR image. When we compare the results from geostatistical analysis of GPR data from selected deltaic and barrier‐spit depositional environments we find different correlation structures in GPR images from different depositional environments. GPR images from braid deltas have near‐horizontal correlation directions and correlation lengths on the order of a few meters. In contrast, the GPR image of a fan‐foreset delta has a very long (>24 m) correlation length and a maximum correlation direction plunging 20°. In the GPR images from barrier spits, we find maximum correlation directions that are horizontal or plunging a few degrees. The correlation lengths range from 7 to 43 m, depending on the orientation of the GPR image relative to spit end growth, and on the specific radar facies that is analyzed.

scholarly journals Ground-penetrating radar profiling on embanked floodplains

2007 ◽  
Vol 86 (1) ◽  
pp. 55-61 ◽  
Author(s):  
M.A.J. Bakker ◽  
D. Maljers ◽  
H.J.T. Weerts
Keyword(s):  
Ground Penetrating Radar ◽  
Sedimentary Facies ◽  
Extreme Floods ◽  
Architectural Elements ◽  
Accommodation Space ◽  
Sand Bars ◽  
Sediment Deposits ◽  
Radar Velocity ◽  
Ground Penetrating ◽  
Radar Facies

AbstractManagement of the Dutch embanked floodplains is of crucial interest in the light of a likely increase of extreme floods. One of the issues is a gradual decrease of floodwater accommodation space as a result of overbank deposition of mud and sand during floods. To address this issue, sediment deposits of an undisturbed embanked floodplain near Winssen along the river Waal were studied using ground-penetrating radar (GPR). A number of radar facies units were recognized. Boreholes were used to relate radar facies units to sedimentary facies and to determine radar velocity. The GPR groundwave is affected by differences in moisture and texture of the top layer and probably interferes with the first subsurface reflector. The architectural elements recognized in the GPR transects confirm earlier reported insights on human-influenced river behaviour. This is testified in the development of sand bars during flood regimes that are probably more widespread than previously established.

scholarly journals Looking through drumlins: testing the application of ground-penetrating rada

2014 ◽  
Vol 60 (224) ◽  
pp. 1126-1134 ◽  
Author(s):  
Matteo Spagnolo ◽  
Edward C. King ◽  
David W. Ashmore ◽  
Brice R. Rea ◽  
Jeremy C. Ely ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Feasibility Study ◽  
Ground Penetrating Radar ◽  
Surface Profile ◽  
Weather Conditions ◽  
Clayey Sediment ◽  
Sedimentary Architecture ◽  
Unfavourable Weather ◽  
Ground Penetrating ◽  
Radar Antenna

AbstractGround-penetrating radar (GPR) is becoming a commonly applied technique in geomorphology. However, its use in the study of subglacial bedforms has yet to be fully explored and exploited. This paper presents the results of a GPR feasibility study conducted on a drumlinized terrain in Cumbria, UK, where five drumlins were investigated using multiple radar antenna frequencies. The site was selected for the presence of nearby bedrock outcrops, suggesting a shallow drumlinized diamict–bedrock contact and a permeable lithology. Despite the clayey sediment and unfavourable weather conditions, a considerable penetration depth of ~12 m was achieved when using a 50 MHz antenna, with a separation of 1 m, trace spacing of 1 m and 128-fold vertical stack. Results indicate that the drumlinized diamict is in direct erosional contact with the bedrock. While the internal drumlin geometry is generally chaotic on the stoss side, evidence of layering dipping downflow at an angle greater than the drumlin surface profile was found on the lee side. The inter-drumlin areas comprise ~4 m of infill sediment that masks part of the original drumlin profile. Overall, this study indicates that GPR can be deployed successfully in the study of glacial bedform sedimentary architecture.

scholarly journals INVESTIGATION OF THE INTERNAL STRUCTURE AND EVOLUTION OF THE HOLOCENE BARRIER OF MARICÁ (RIO DE JANEIRO, BRAZIL)

2015 ◽  
Vol 33 (3) ◽  
pp. 461
Author(s):  
Carolina Pereira Silvestre ◽  
André Luiz Carvalho da Silva ◽  
Maria Augusta Martins da Silva ◽  
Amilsom Rangel Rodrigues
Keyword(s):  
Internal Structure ◽  
Sea Level ◽  
Ground Penetrating Radar ◽  
Rio De Janeiro ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
The Holocene ◽  
Sea Level Fluctuations ◽  
Sedimentary Architecture ◽  
Ground Penetrating

ABSTRACT. The objective of this study is the identification of the internal structure of the Holocene barrier of the Maricá coastal plain (Rio de Janeiro, Brazil) for the understanding of the evolution of this coast. The regional geomorphology is characterized by the large Maricá lagoon and by two sandy barriers which confines a series of small near-dry lagoons. Geophysical data obtained from ground-penetrating radar (GPR) images, with 400 and 200 MHz shielded antennae and borehole samples, both reaching down to about 10 meters in depth, provided information about the sedimentary architecture and geological and oceanographical processes responsible for the evolution of this area in the Holocene. The results show that the barrier internal structure is formed by a set of strata presenting different geometries, dip directions and organization, relative to the following depositional environments: dunes, washover fans, beach and tidal channels. It was possible to determine the importance of the sea level changes, longshore currents and overwash processes for the barrier development. Strong reflectors representing eolian strata dipping towards the continent point out to a phase of barrier retrogradation; afterwards, a succession of very well preserved beach paleoscarps, located south of the previous barrier, shows a phase of barrier progradation. Such evidences indicate that the barrier evolved according to the Holocene sea level fluctuations recognized for the Brazilian coast.Keywords: ground-penetrating radar, barrier-lagoon system, Holocene, Maricá coast. RESUMO. O presente estudo objetivou identificar a estrutura interna da barreira holocênica buscando compreender a evolução da planície costeira de Maricá (Rio de Janeiro). A geomorfologia regional é caracterizada pela Lagoa de Maricá e duas barreiras arenosas, separadas por pequenas lagunas colmatadas. Dados geofísicos obtidos com um georadar, com antenas de 400 e 200 MHz, e amostras de sondagem geológica, ambos até a profundidade média de 10 metros, forneceram informações sobre a arquitetura sedimentar e os processos geológicos e oceanográficos responsáveis pela evolução desta área no Holoceno. Os resultados mostram que a estrutura interna da barreira é formada por um conjunto de estratos de diferentes geometrias, direções de mergulho e modos de organização relacionados aos seguintes ambientes deposicionais: dunas, leques de arrombamento, praias e canais de maré. Essas características permitiram o entendimento da dinâmica costeira responsável pelo desenvolvimento da barreira, com destaque para as variações do nível do mar, correntes de deriva litorânea e mecanismos de sobrelavagem. Refletores marcantes representando estratos eólicos inclinados para o continente indicam uma fase de retrogradação da barreira; a esse episódio se seguiu um período marcado por sucessivas paleoescarpas de tempestade, localizadas mais ao sul, indicando uma fase de progradação. Essas evidências mostram que a barreira evoluiu de acordo com as fases de transgressão e regressão marinha do Holoceno reconhecidas para o litoral brasileiro.Palavras-chave: georadar, sistema barreira-laguna, Holoceno, litoral de Maricá.

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