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David Beamish - One of the best experts on this subject based on the ideXlab platform.
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peat mapping associations of airborne Radiometric Survey data
Remote Sensing, 2014Co-Authors: David BeamishAbstract:This study considers recent airborne Radiometric (gamma ray) Survey data, obtained at high-resolution, across various regions of the UK. The datasets all display a very evident attenuation of signal in association with peat, and intra-peat variations are observed. The geophysical response variations are examined in detail using example data sets across lowland areas (raised bogs, meres, fens and afforested peat) and upland areas of blanket bog, together with associated wetland zones. The Radiometric data do not map soils per se. The bedrock (the radiogenic parent) provides a specific amplitude level. Attenuation of this signal level is then controlled by moisture content in conjunction with the density and porosity of the soil cover. Both soil and bedrock variations need to be jointly assessed. The attenuation theory, reviewed here, predicts that the behaviour of wet peat is distinct from most other soil types. Theory also predicts that the attenuation levels observed across wet peatlands cannot be generally used to map variations in peat thickness. Four Survey areas at various scales, across England, Scotland, Wales and Ireland are used to demonstrate the ability of the airborne data to map peat zones. A 1:50 k national mapping of deep peat is used to provide control although variability in the definition of peat zones across existing databases is also demonstrated.
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optimal mapping of terrestrial gamma dose rates using geological parent material and aerogeophysical Survey data
Journal of Environmental Monitoring, 2012Co-Authors: B G Rawlins, C Scheib, Andrew N Tyler, David BeamishAbstract:Regulatory authorities need ways to estimate natural terrestrial gamma radiation dose rates (nGy h−1) across the landscape accurately, to assess its potential deleterious health effects. The primary method for estimating outdoor dose rate is to use an in situ detector supported 1 m above the ground, but such measurements are costly and cannot capture the landscape-scale variation in dose rates which are associated with changes in soil and parent material mineralogy. We investigate the potential for improving estimates of terrestrial gamma dose rates across Northern Ireland (13 542 km2) using measurements from 168 sites and two sources of ancillary data: (i) a map based on a simplified classification of soil parent material, and (ii) dose estimates from a national-scale, airborne Radiometric Survey. We used the linear mixed modelling framework in which the two ancillary variables were included in separate models as fixed effects, plus a correlation structure which captures the spatially correlated variance component. We used a cross-validation procedure to determine the magnitude of the prediction errors for the different models. We removed a random subset of 10 terrestrial measurements and formed the model from the remainder (n = 158), and then used the model to predict values at the other 10 sites. We repeated this procedure 50 times. The measurements of terrestrial dose vary between 1 and 103 (nGy h−1). The median absolute model prediction errors (nGy h−1) for the three models declined in the following order: no ancillary data (10.8) > simple geological classification (8.3) > airborne Radiometric dose (5.4) as a single fixed effect. Estimates of airborne Radiometric gamma dose rate can significantly improve the spatial prediction of terrestrial dose rate.
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a Radiometric airborne geophysical Survey of the isle of wight
Proceedings of the Geologists' Association, 2011Co-Authors: David Beamish, James C. WhiteAbstract:A high resolution airborne geophysical Survey across the Isle of Wight and Lymington area conducted in 2008 provided the first modern Radiometric Survey across the geological formations that characterise much of southern England. The basic Radiometric data are presented and it is evident that bedrock geology exerts a controlling influence on the broad response characteristics of the naturally occurring radioelements. A GIS-based geological classification of the data provides a quantitative assessment and reveals that a relatively high percentage of the variability of the data is explained by the Cretaceous bedrock geology but this is much reduced in the Palaeogene. The three traditional Chalk units (Lower, Middle and Upper Chalk depicted on the currently available Geological Map) provide the lowest and most distinct behaviour within the Cretaceous sequence. Mineral content within the Chalk appears to increase with increasing age. A new method of representing the baseline Radiometric information from the Survey in terms of the mean values of the geological classification is presented. The variation of radioelement geochemistry within individual formations is examined in two case studies from the Cretaceous Lower Greensand Group and the Palaeogene Hamstead Member (Bouldnor Formation). The Cretaceous sequences provide the higher levels of discrimination of localised variations in radioelement distributions. A more detailed case study examines the potential influences from the degree of water saturation in the soil and superficial deposits.
B G Rawlins - One of the best experts on this subject based on the ideXlab platform.
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optimal mapping of terrestrial gamma dose rates using geological parent material and aerogeophysical Survey data
Journal of Environmental Monitoring, 2012Co-Authors: B G Rawlins, C Scheib, Andrew N Tyler, David BeamishAbstract:Regulatory authorities need ways to estimate natural terrestrial gamma radiation dose rates (nGy h−1) across the landscape accurately, to assess its potential deleterious health effects. The primary method for estimating outdoor dose rate is to use an in situ detector supported 1 m above the ground, but such measurements are costly and cannot capture the landscape-scale variation in dose rates which are associated with changes in soil and parent material mineralogy. We investigate the potential for improving estimates of terrestrial gamma dose rates across Northern Ireland (13 542 km2) using measurements from 168 sites and two sources of ancillary data: (i) a map based on a simplified classification of soil parent material, and (ii) dose estimates from a national-scale, airborne Radiometric Survey. We used the linear mixed modelling framework in which the two ancillary variables were included in separate models as fixed effects, plus a correlation structure which captures the spatially correlated variance component. We used a cross-validation procedure to determine the magnitude of the prediction errors for the different models. We removed a random subset of 10 terrestrial measurements and formed the model from the remainder (n = 158), and then used the model to predict values at the other 10 sites. We repeated this procedure 50 times. The measurements of terrestrial dose vary between 1 and 103 (nGy h−1). The median absolute model prediction errors (nGy h−1) for the three models declined in the following order: no ancillary data (10.8) > simple geological classification (8.3) > airborne Radiometric dose (5.4) as a single fixed effect. Estimates of airborne Radiometric gamma dose rate can significantly improve the spatial prediction of terrestrial dose rate.
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airborne Radiometric Survey data and a dtm as covariates for regional scale mapping of soil organic carbon across northern ireland
European Journal of Soil Science, 2009Co-Authors: B G Rawlins, R M Lark, B P Marchant, Dermot Smyth, C Scheib, C JordanAbstract:Soil scientists require cost-effective methods to make accurate regional predictions of soil organic carbon (SOC) content. We assess the suitability of airborne Radiometric data and digital elevation data as covariates to improve the precision of predictions of SOC from an intensive Survey in Northern Ireland. Radiometric data (K band) and, to a lesser extent, altitude are shown to increase the precision of SOC predictions when they are included in linear mixed models of SOC variation. However the statistical distribution of SOC in Northern Ireland is bimodal and therefore unsuitable for geostatistical analysis unless the two peaks can be accounted for by the fixed effects in the linear mixed models. The upper peak in the distribution is due to areas of peat soils. This problem may be partly countered if soil maps are used to classify areas of Northern Ireland according to their expected SOC content and then different models are fitted to each of these classes. Here we divide the soil in Northern Ireland into three classes, namely mineral, organo-mineral and peat. This leads to a further increase in the precision of SOC predictions and the median square error is 2.2 %2. However a substantial number of our observations appear to be mis-classified and therefore the mean squared error in the predictions is larger (30.6 %2) since it is dominated by large errors due to mis-classification. Further improvement in SOC prediction may therefore be possible if better delineation between areas of large SOC (peat) and small SOC (non-peat) could be achieved.
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understanding airborne Radiometric Survey signals across part of eastern england
Earth Surface Processes and Landforms, 2007Co-Authors: B G Rawlins, R M Lark, R WebsterAbstract:A low-level airborne Radiometric Survey provides data on the concentrations of gammaemitting elements including potassium (K), thorium (Th) and uranium (U) in the upper half metre of the soil. Where weathering has not penetrated much beyond this depth, as in the young soils that cover much of England and Wales, the signal is likely to be related to the soil's clay content and its parent material. In these situations Radiometric Survey could be valuable for mapping soil digitally. We wished to understand how the Radiometric signal relates to parent material and soil geochemistry, and to identify the spatial structure, if not the sources, of any unexplained variation. We analysed the joint spatial variation of the airborne gamma signal and high-resolution soil geochemical Survey data across part of eastern England by modelling their coregionalization. We also used reml to assess the joint effects of soil geochemistry and parent material on the Radiometric signals of K and Th. The overall correlations of Radiometric estimates with soil Survey data for K and Th were large, as were the structural correlations for components of variation spatially dependent up to 49 and 16 km for K and Th respectively. This suggests that the Radiometric signals for these two elements provide effective estimates of the amounts in the soil and their patterns of distribution. Although class of parent material accounted for a third of of the variance in the Radiometric K signal, much of the variation within the classes is explained by geochemistry, suggesting that subtler changes can be detected. A larger proportion of the Th signal was accounted for by parent material. This supports our expectation that Radiometric signals for K and Th provide information on parent material in the young landscapes of England and Wales. We are therefore confident that airborne Radiometric Surveys would be useful for making thematic maps of soil, particularly the soil's texture and closely related properties across England and Wales. Copyright © 2007 Natural Environment Research Council. Published in 2007 by John Wiley & Sons, Ltd.
Mark Duffett - One of the best experts on this subject based on the ideXlab platform.
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mineral resources tasmania tiers airborne magnetic and Radiometric Survey data released
Preview, 2021Co-Authors: Mark DuffettAbstract:The data obtained by the Tiers airborne magnetic and Radiometric Survey in February-April 2021 have now been finalised and are available for download via the Mineral Resources Tasmania (https://www...
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mineral resources tasmania tiers airborne magnetic and Radiometric Survey update
Preview, 2021Co-Authors: Mark DuffettAbstract:After a long gestation period, the Tiers airborne magnetic and Radiometric Survey spanning central and eastern Tasmania was flown through February and March, with acquisition likely completed aroun...
R Ravisankar - One of the best experts on this subject based on the ideXlab platform.
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data on the Radiometric Survey over a kaolinitic terrain in dahomey basin nigeria
Data in Brief, 2018Co-Authors: T A Adagunodo, Olaide Sakiru Hammed, M R Usikalu, Williams A Ayara, R RavisankarAbstract:Abstract This article consists the in situ data sets of activity concentrations of radionuclides (K-40, Th-232 and U-238) and gamma radiation dose rates measured about 1 m above a kaolinitic terrain in Ifonyintedo, Dahomey Basin, SW Nigeria. Nineteen (19) data points were randomly occupied at the lower axis of the kaolin field using a hand-held detector known as Super-Spec (RS 125). At each data point, the measurements were taken four times, while their averages and standard deviations were estimated in order to ensure accuracy. The Radiometric Survey was carried out between December, 2017 and January, 2018. The data sets were processed and analyzed via a descriptive statistics. The data can be explored further by estimating the radiological risks to the miners on the field, and to correlate the activity concentrations of the data with the activity concentrations of the tiles that are produced from the kaolin deposits in Ifonyintedo. Furthermore, the data from this article could be compared with other data acquired over a kaolinitic terrain across the globe.
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radioactivity and radiological hazards from a kaolin mining field in ifonyintedo nigeria
MethodsX, 2018Co-Authors: T A Adagunodo, A I George, I A Ojoawo, K Ojesanmi, R RavisankarAbstract:The concentrations of the radionuclides in the subsurface formation (soils and rocks) solely depend on their geological origin, which enables its variation from point to point on the Crust. Construction materials can possess elevated concentrations of radioactivity if their byproducts are mined from contaminated radionuclide sources. In this article, results of in situ measurements of radioactivity concentrations of 40K, 232Th, and 238U as well as gamma doses and radiological hazards from kaolin mining field were presented and evaluated. Eleven stations were randomly occupied in order to cover the upper axis of a kaolin mining field in Ifonyintedo. The Radiometric Survey was achieved using Super-Spec (RS-125), equipment capable of measuring activity concentrations and gamma doses. For each location, measurements were taken four times, while its mean and standard deviation values were estimated for better accuracy. The overall mean activity concentrations (for 40K, 232Th and 238U) and gamma dose were estimated as 93.9 Bq kg-1, 65.1 Bq kg-1, 38.2 Bq kg-1, and 59.6 nGyh-1 respectively. The estimated radiological hazards from the measured parameters showed that the overall mean concentrations of Radium Equivalent, External and Internal Hazards, Annual Effective Dose, Gamma and Alpha Indices, and Representative Level index are 138.5 Bq kg-1, 0.37 0.48, 0.29 mSvyr-1, 0.48, 0.19, and 0.97 respectively. By comparing the mean values of the activity concentrations and their radiological risks with the several world standards from the literature, kaolin deposits in Ifonyintedo are highly rich in thorium.
R M Lark - One of the best experts on this subject based on the ideXlab platform.
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airborne Radiometric Survey data and a dtm as covariates for regional scale mapping of soil organic carbon across northern ireland
European Journal of Soil Science, 2009Co-Authors: B G Rawlins, R M Lark, B P Marchant, Dermot Smyth, C Scheib, C JordanAbstract:Soil scientists require cost-effective methods to make accurate regional predictions of soil organic carbon (SOC) content. We assess the suitability of airborne Radiometric data and digital elevation data as covariates to improve the precision of predictions of SOC from an intensive Survey in Northern Ireland. Radiometric data (K band) and, to a lesser extent, altitude are shown to increase the precision of SOC predictions when they are included in linear mixed models of SOC variation. However the statistical distribution of SOC in Northern Ireland is bimodal and therefore unsuitable for geostatistical analysis unless the two peaks can be accounted for by the fixed effects in the linear mixed models. The upper peak in the distribution is due to areas of peat soils. This problem may be partly countered if soil maps are used to classify areas of Northern Ireland according to their expected SOC content and then different models are fitted to each of these classes. Here we divide the soil in Northern Ireland into three classes, namely mineral, organo-mineral and peat. This leads to a further increase in the precision of SOC predictions and the median square error is 2.2 %2. However a substantial number of our observations appear to be mis-classified and therefore the mean squared error in the predictions is larger (30.6 %2) since it is dominated by large errors due to mis-classification. Further improvement in SOC prediction may therefore be possible if better delineation between areas of large SOC (peat) and small SOC (non-peat) could be achieved.
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understanding airborne Radiometric Survey signals across part of eastern england
Earth Surface Processes and Landforms, 2007Co-Authors: B G Rawlins, R M Lark, R WebsterAbstract:A low-level airborne Radiometric Survey provides data on the concentrations of gammaemitting elements including potassium (K), thorium (Th) and uranium (U) in the upper half metre of the soil. Where weathering has not penetrated much beyond this depth, as in the young soils that cover much of England and Wales, the signal is likely to be related to the soil's clay content and its parent material. In these situations Radiometric Survey could be valuable for mapping soil digitally. We wished to understand how the Radiometric signal relates to parent material and soil geochemistry, and to identify the spatial structure, if not the sources, of any unexplained variation. We analysed the joint spatial variation of the airborne gamma signal and high-resolution soil geochemical Survey data across part of eastern England by modelling their coregionalization. We also used reml to assess the joint effects of soil geochemistry and parent material on the Radiometric signals of K and Th. The overall correlations of Radiometric estimates with soil Survey data for K and Th were large, as were the structural correlations for components of variation spatially dependent up to 49 and 16 km for K and Th respectively. This suggests that the Radiometric signals for these two elements provide effective estimates of the amounts in the soil and their patterns of distribution. Although class of parent material accounted for a third of of the variance in the Radiometric K signal, much of the variation within the classes is explained by geochemistry, suggesting that subtler changes can be detected. A larger proportion of the Th signal was accounted for by parent material. This supports our expectation that Radiometric signals for K and Th provide information on parent material in the young landscapes of England and Wales. We are therefore confident that airborne Radiometric Surveys would be useful for making thematic maps of soil, particularly the soil's texture and closely related properties across England and Wales. Copyright © 2007 Natural Environment Research Council. Published in 2007 by John Wiley & Sons, Ltd.
