Evidence for glacial geological controls on the hydrology of Maine (USA) peatlands

Geology ◽  
2020 ◽  
Vol 48 (8) ◽  
pp. 771-776
Author(s):  
Xi Chen ◽  
Xavier Comas ◽  
Andrew Reeve ◽  
Lee Slater
Keyword(s):  
Ground Penetrating Radar ◽  
Peat Soil ◽  
Spatial Association ◽  
Geochemical Data ◽  
Atmospheric Methane ◽  
Multiple Sources ◽  
Ch4 Production ◽  
Geological Factors ◽  
Ground Penetrating

Abstract Freshwater pools commonly form eccentric crescent patterns in peatlands, an important atmospheric methane (CH4) source, and show an apparent spatial association with eskers in some deglaciated regions. However, the role of underlying permeable glacial deposits such as eskers in regulating hydrogeology, and perhaps even carbon cycling, in peatlands is rarely considered. In this study, ground-penetrating radar imaging and direct coring confirmed that clustered pools coincide with buried esker crests in contact with peat soil in Caribou Bog and Kanokolus Bog in Maine (USA). Hydraulic head and geochemical data combined with lidar indicate vertical water flow from shallow peat toward the permeable esker crests, suggesting enhanced downward transport of labile organic carbon that presumably accelerates rates of methanogenesis in deep peat. Eskers might therefore serve as proxies for enhanced CH4 production in deep peat, as supported by differences in dissolved CH4 profiles depending on proximity to pools. Geographic data compiled from multiple sources suggest that many peatlands with eccentric pools appear to be located proximal to esker systems in Maine and Fennoscandia. These geological factors may be important, previously unrecognized controls on water and the carbon cycle in peatlands.

REFLECTION COEFFICIENT OF AN ELECTROMAGNETIC WAVE IN CONDUCTIVE MEDIA

2018 ◽  
pp. 100-106
Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov
Keyword(s):  
Reflection Coefficient ◽  
Ground Penetrating Radar ◽  
Electromagnetic Waves ◽  
Water Contamination ◽  
Survey Design ◽  
Direct And Inverse Problems ◽  
The Difference ◽  
Ground Penetrating ◽  
Ideal Dielectric

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.

scholarly journals Performance of Soil Water Content Using Ground Penetrating Radar with Different Antenna Frequencies

2018 ◽  
Vol 7 (2.29) ◽  
pp. 815
Author(s):  
Nurul Izzati Abd Karim ◽  
Samira Albati Kamaruddin ◽  
Rozaimi Che Hasan
Keyword(s):  
Dielectric Permittivity ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Ground Penetrating Radar ◽  
Peat Soil ◽  
Relative Dielectric Permittivity ◽  
Depth Of Penetration ◽  
Engineering Research ◽  
Ground Penetrating

Accurate measurements of Soil Water Content (SWC) with applicable and relevant support are essential in many fields of earth and soil engineering research. Ground Penetrating Radar (GPR) is a geophysical tool that measures and provides accurate results for determination of the SWC. To prove the accuracy of SWC measurement using GPR, a field survey was performed in peat soil. This paper presents a fieldwork survey with the aim of assessing the SWC measurement using GPR. The survey work was conducted at Johor Bharu using different antenna frequencies (250 and 700 MHz). Five profiles, which is 5m by 5m in length, were scanned along an east-west direction with a common offset at an equal spacing of 1m.  To measure the SWC using GPR, the researchers used the velocity from the GPR’s signal from the receiving antenna to the soil. Statistical analysis was carried out based on the dielectric permittivity and SWC. Schaap’s equation and Roth’s equation were used to distinguish the relative dielectric permittivity of the soil to SWC. The results of this study show the linear function,  for the measured SWC. The validation graph shows that at a frequency of 250 MHz, the depth of penetration was greater compared to the frequency of 750 MHz. These results, suggest that a higher frequency will give higher resolution but lower depth penetration.  

Estimating winter ebullition bubble volume in lake ice using ground-penetrating radar

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. H13-H25 ◽  
Author(s):  
Nadia Fantello ◽  
Andrew D. Parsekian ◽  
Katey M. Walter Anthony
Keyword(s):  
Ground Penetrating Radar ◽  
Growth Models ◽  
Field Measurements ◽  
Gas Content ◽  
Atmospheric Methane ◽  
Lake Ice ◽  
Electromagnetic Models ◽  
Lake Bottom Sediments ◽  
Ground Penetrating ◽  
Gas Volume

Freshwater lakes are an important source of atmospheric methane ([Formula: see text]); however, uncertainties associated with quantifying fluxes limit the accuracy of climate warming projections. Among emission pathways, ebullition (bubbling) is the principal and most challenging to account for given its spatial and temporal patchiness. When lakes freeze, many methane-rich bubbles escaping from lake-bottom sediments are temporarily trapped by downward-growing lake ice. Because bubble position is then seasonally fixed, we postulate that it should be possible to locate bubbles using a geophysical approach sensitive to perturbations in the ice-water interface and ice sheet structure generated by bubbles. We use ground-penetrating radar (GPR) to noninvasively quantify the amount of ebullition gas present in lake ice. To do this, an appropriate petrophysical transformation is required that relates radar wave velocity and volumetric gas content. We use laboratory experiments to show that electromagnetic models and volumetric mixing formulas were good representations of the gas volume-permittivity relationship. We found a standard deviation in dielectric permittivity between the models of 0.03, 0.03, and 0.02 for 20%, 50%, and 70% gas content, respectively. Second, by combining two GPR geometries (common and multioffset), we were able to locate bubbles and estimate gas volume with low uncertainty, with [Formula: see text] being the lowest uncertainty found and [Formula: see text] the largest. Finally, we found that GPR reflection patterns were associated with different previously identified ice-bubble classes. These geophysical results coupled with ancillary field measurements and ice-growth models also suggest how GPR can contribute to estimates of seasonal and annual ebullition fluxes over large spatiotemporal scales within and among lakes, thereby helping to reduce uncertainties in upscaled estimates of ecosystem methane emissions.

scholarly journals Imaging tropical peatlands in Indonesia using ground-penetrating radar (GPR) and electrical resistivity imaging (ERI): implications for carbon stock estimates and peat soil characterization

2015 ◽  
Vol 12 (10) ◽  
pp. 2995-3007 ◽  
Author(s):  
X. Comas ◽  
N. Terry ◽  
L. Slater ◽  
M. Warren ◽  
R. Kolka ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ground Penetrating Radar ◽  
Peat Soil ◽  
Mineral Soil ◽  
Electrical Resistivity Imaging ◽  
Resistivity Imaging ◽  
C Storage ◽  
Tropical Peatlands ◽  
Ground Penetrating ◽  
Soil Interface

Abstract. Current estimates of carbon (C) storage in peatland systems worldwide indicate that tropical peatlands comprise about 15% of the global peat carbon pool. Such estimates are uncertain due to data gaps regarding organic peat soil thickness, volume and C content. We combined a set of indirect geophysical methods (ground-penetrating radar, GPR, and electrical resistivity imaging, ERI) with direct observations using core sampling and C analysis to determine how geophysical imaging may enhance traditional coring methods for estimating peat thickness and C storage in a tropical peatland system in West Kalimantan, Indonesia. Both GPR and ERI methods demonstrated their capability to estimate peat thickness in tropical peat soils at a spatial resolution not feasible with traditional coring methods. GPR is able to capture peat thickness variability at centimeter-scale vertical resolution, although peat thickness determination was difficult for peat columns exceeding 5 m in the areas studied, due to signal attenuation associated with thick clay-rich transitional horizons at the peat–mineral soil interface. ERI methods were more successful for imaging deeper peatlands with thick organomineral layers between peat and underlying mineral soil. Results obtained using GPR methods indicate less than 3% variation in peat thickness (when compared to coring methods) over low peat–mineral soil interface gradients (i.e., below 0.02°) and show substantial impacts in C storage estimates (i.e., up to 37 MgC ha−1 even for transects showing a difference between GPR and coring estimates of 0.07 m in average peat thickness). The geophysical data also provide information on peat matrix attributes such as thickness of organomineral horizons between peat and underlying substrate, the presence of buried wood, buttressed trees or tip-up pools and soil type. The use of GPR and ERI methods to image peat profiles at high resolution can be used to further constrain quantification of peat C pools and inform responsible peatland management in Indonesia and elsewhere in the tropics.

scholarly journals Experimental assessment of the viability of using ground penetrating radar for metal wire-snare detection

Crime Science ◽  
2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Hervé Borrion ◽  
Amin Amiri ◽  
Dorothea Delpech ◽  
A. M. Lemieux
Keyword(s):  
National Parks ◽  
Situation Awareness ◽  
Ground Penetrating Radar ◽  
Natural Habitat ◽  
Wildlife Crime ◽  
Illicit Trade ◽  
Security Personnel ◽  
Practical Challenge ◽  
Ground Penetrating

Abstract Wildlife crime is an international issue with the illicit trade of flora and fauna estimated to be worth several billion dollars. In national parks, the problem can often be summarised as an arms race, with poachers trying to remain undetected by park rangers and other security personnel that are trying to protect the natural habitat and species from exploitation. Within this context, the detection of wire snares is a critical step. Not only can it reduce the number of animals caught by poachers but it can also help rangers develop better situation awareness and, in turn, improve patrolling strategies. To address the practical challenge of wire-snare detection across wide areas, this article examines the capacity of ground penetrating radar (GPR). Using two snares of small and medium sizes, the experiment confirmed the promising role of this technology, even if poachers attempt to conceal the snares underneath small tree branches and roots.

The role of ground penetrating radar and geostatistics in reservoir description

1997 ◽  
Vol 16 (11) ◽  
pp. 1576-1584 ◽  
Author(s):  
Rosemary Knight ◽  
Paulette Tercier ◽  
Harry Jol
Keyword(s):  
Ground Penetrating Radar ◽  
Reservoir Description ◽  
Ground Penetrating

scholarly journals Results of Comprehensive Geophysical Studies on the Search for Crypts on the Territory of Suburban Necropolis of Tauric Chersonese in the Karantinnaya Balka

2021 ◽  
Vol 247 ◽  
pp. 1-9
Author(s):  
Vladimir Glazunov ◽  
Alexey Ageev ◽  
Gleb Gorelik ◽  
Tatyana Sarapulkina
Keyword(s):  
Ground Penetrating Radar ◽  
Geophysical Methods ◽  
Electrical Tomography ◽  
Interior Space ◽  
Archaeological Heritage ◽  
Saint Petersburg ◽  
State Museum ◽  
Geological Factors ◽  
Ground Penetrating ◽  
First Time

The article presents the results of comprehensive studies carried out by the research team of Saint Petersburg Mining University in cooperation with the specialists from the State Museum-Preserve "Tauric Chersonese" in 2019. The purpose of the work was to discover and map antique and medieval crypts (ancient burial structures) on the territory of suburban necropolis of Tauric Chersonese in the Karantinnaya balka. The complex of geophysical methods included continuous ground penetrating radar sounding at two center frequencies of 350 and 500 MHz and contactless electrical tomography. To minimize spatial errors in the process of studies, topographic and geodetic works were carried out. For the first time wave electromagnetic effects were identified, which indicated the positions of hidden underground crypts. Geological factors were established that are favorable for cutting crypts in the layered thickness of Sarmatian limestones. The obtained results allowed to justify the feasibility of continuing geophysical works at the necropolis in order to study interior space of the discovered crypts and to determine the boundaries of archaeological heritage.

Sign in / Sign up

Export Citation Format

Share Document