none 10.2113/JEEG11.1.53 Environmental and Engineering Geophysical Society Environmental and Engineering Geophysical Society 2613 24456688 59784 2026010708535543700 10.32389 2026-01-07T13:54:05Z 2006-11-16T15:34:14Z 17 Journal of Environmental and Engineering Geophysics 1943-2658 1083-1363 03 2006 03 01 2006 03 01 2006 11 1 A. Ruffell School of Geography, Queen's University, Belfast, N. Ireland School of Geography, Queen's University, Belfast, N. Ireland J.M. McKinley School of Geography, Queen's University, Belfast, N. Ireland School of Geography, Queen's University, Belfast, N. Ireland C.D. Lloyd School of Geography, Queen's University, Belfast, N. Ireland School of Geography, Queen's University, Belfast, N. Ireland C. Graham School of Geography, Queen's University, Belfast, N. Ireland Abstract Spectral gamma-ray data can be obtained by non-destructive, automated, rapid and inexpensive survey methods. Previous studies utilise only total count, or total count as well as K, U and Th data. This work examines the use of Th/K and Th/U ratios to define the subsurface extent of partially-buried features at the centimeter to meter scale. On-site results are presented from two case studies as two-dimensional cross-sections. Changes in Th/K and Th/U ratios coincide with the known location of buried structures to within 10 cm horizontal resolution. Gradual changes in total count, K, U and Th measurements give a lower horizontal accuracy of 30 cm to 1 m. Grids of data were manipulated in ArcGISTM using a thin plate spline function to maximise information use and provide ‘easy to interpret’ maps of the survey areas. Unlike total count or individual element maps, Th/K and Th/U ratio maps can be compared to the known location of subsurface structures, vindicating the use of ratio cross-sections and maps in archaeological, geotechnical and forensic applications. It is concluded that the capacity to observe sub-surface features is enhanced through the use of Th/K and Th/U ratios. 03 2006 03 01 2006 03 01 2006 53 61 10.2113/JEEG11.1.53 https://pubs.geoscienceworld.org/jeeg/article/11/1/53/139248/Th-K-and-Th-U-Ratios-from-Spectral-Gamma-Ray https://pubs.geoscienceworld.org/eegs/jeeg/article-pdf/11/1/53/3009519/53.pdf https://pubs.geoscienceworld.org/eegs/jeeg/article-pdf/11/1/53/3009519/53.pdf https://pubs.geoscienceworld.org/jeeg/article/11/1/53/139248/th-k-and-th-u-ratios-from-spectral-gamma-ray http://library.seg.org/doi/abs/10.2113/JEEG11.1.53 Journal of Applied Geophysics Ayres 48 1 2001 10.1016/S0926-9851(01)00053-2 Natural gamma-ray activity compared to geotechnical and environmental characteristics of near surface sediments Chang 2002 Introduction to geographic information systems Journal of Applied Geophysics Chiozzi 38 209 1998 10.1016/S0926-9851(97)00035-9 Ground radiometric survey of U, Th and K on the Lipari Island, Italy Darnley 1987 Regional airborne gamma-ray surveys: A review High resolution sequence stratigraphy: Innovations and applications Davies 104 25 1996 Spectral gamma ray characterization of high resolution sequence stratigraphy: Examples from Upper Carboniferous fluvio-deltaic systems, County Clare, Ireland Journal of Applied Geophysics El Nabi 42 105 1995 Statistical evaluation of airborne gamma-ray spectroscopic data from the Magal Gebriel area, south Eastern Desert Mineral deposit studies in Nova Scotia, Volume 2 Ford 71 1993 Radioelement mapping of parts of the Musquodoboit Batholith and Liscomb complex, Meguma zone Nova Scotia Computer Aided Geometric Design Franke 2 87 1985 10.1016/0167-8396(85)90011-1 Thin plate splines with tension Journal of Applied Geophysics Gautam 45 97 2000 10.1016/S0926-9851(00)00022-7 Mapping subsurface karst structure with gamma ray and electrical resistivity profiles: A case study from Pokhara Geological Magazine Hadley 137 137 2000 10.1017/S0016756800003976 Gamma-ray spectroscopy in structural correlations: An example from the Neoproterozoic succession of Donegal (NW Ireland) Geological applications of wireline logs Hurst 48 211 1990 Natural gamma-ray spectrometry in hydrocarbon-bearing sandstones from the Norwegian continental shelf Geoderma Hutchinson 62 45 1994 10.1016/0016-7061(94)90027-2 Splines—More than just a smooth interpolator Johnston 2001 Using ArcGIS™ geostatistical analyst Jones 2002 Use of gamma-ray spectrometry for Archaeological site investigations Kearey 280 2002 An introduction to geophysical exploration Computers and Mathematics with Applications Mitáš 16 983 1988 10.1016/0898-1221(88)90255-6 General variational approach to the interpolation problem Geographical information systems. Volume I: Principles and technical issues Mitáš 2nd ed. 481 1999 Spatial interpolation Journal of Applied Geophysics Moussa 48 137 2001 10.1016/S0926-9851(01)00077-5 Gamma-ray spectrometry: A new tool for exploring archaeological sites: A case study from East Sinai, Egypt Uranium-series disequilibrium: Applications to earth, marine and environmental sciences Osmond 259 1992 Uranium-series mobilisation and surface hydrology Uranium-series disequilibrium: Applications to earth, marine and environmental sciences Rosholt 167 1992 Mobilisation and weathering Archaeological Prospection Ruffell 5 203 1998 10.1002/(SICI)1099-0763(199812)5:4<203::AID-ARP96>3.0.CO;2-D Shallow ground investigation using radiometrics and spectral gamma-ray data Shives 741 1997 The detection of potassic alteration by gamma-ray spectrometry—Recognition of alteration related to mineralization Geological applications of wireline logs II Slatt 65 3 1992 Outcrop gamma-ray logging to improve understanding of subsurface well log correlations Journal of Environmental Radioactivity Tyler 45 235 1999 10.1016/S0265-931X(98)00110-6 Monitoring Anthropogenic Radioactivity in Salt Marsh Environments through in situ gamma ray spectrometry An introduction with applications Wackernagel 3rd ed. 2003 Multivariate geostatistics