Skip to main content
Article thumbnail
Location of Repository

Aeromagnetic data in the UK : a study of the information content of baseline and modern surveys across Anglesey, North Wales

By David Beamish and James C. White


A number of modern, multiparameter, high resolution airborne geophysical surveys (termed HiRES) have been conducted over the past decade across onshore UK. These were undertaken, in part, as a response to the limited resolution of the existing UK national baseline magnetic survey data set acquired in the late 1950s and early 1960s. Modern magnetic survey data, obtained with higher precision and reduced line spacing and elevation, provide an improved data set; however the distinctions between the two available resources, existing and new, are rarely quantified. In this contribution we demonstrate and quantify the improvements that can be anticipated using the new data. The information content of the data sets is examined using a series of modern processing and modelling procedures that provide a full assessment of their resolution capabilities. The framework for the study involves two components. The first relates to the definition of the shallow magnetic structure in relation to an ongoing 1:10 k and 1:50 k geological map revision. The second component relates to the performance of the datasets in defining maps of magnetic basement and assisting with larger scale geological and structural interpretation. One of the smaller HiRES survey areas, the island of Anglesey (Ynys Môn), off the coast of NW Wales is used to provide a series of comparative studies. The geological setting here is both complex and debated and cultural interference is prevalent in the low altitude modern survey data. It is demonstrated that successful processing and interpretation can be carried out on data that have not been systematically corrected (decultured) for non-geological perturbations. Across the survey area a wide number of near-surface magnetic features are evident and are dominated by a reversely magnetized Palaeogene dyke swarm that extends offshore. The average depth to the upper surfaces of the dykes is found to be 44 m. The existing baseline data are necessarily limited in resolving features <1 km in scale; however a detailed comparison of the existing and new data reveals the extent to which these quasi-linear features can be resolved and mapped. The precise limitations of the baseline data in terms of detection, location and estimated depth are quantified. The spectral content of both data sets is examined and the longest wavelength information is extracted to estimate the resolution of magnetic basement features in the two data sets. A significant finding is the lack of information in the baseline data set across wavelengths of between 1 and ∼10 km. Here the HiRES data provide a detailed mapping of shallow magnetic basement features (1–3 km) that display a relevance to current understanding of the fault-bounded terranes that cross the survey area. Equally, the compact scale of the modern survey does not provide deeper (>3 km to upper surface) assessments of magnetic basement. This further assessment is successfully provided by the larger scale baseline data which locates and defines a mid-crustal magnetic basement feature, centred beneath the Snowdon Massif, and illustrates that basement of similar characteristic extends beneath much of Anglesey.\ud \u

Publisher: Wiley
Year: 2011
DOI identifier: 10.1111/j.1365-246X.2010.04852.x
OAI identifier:

Suggested articles


  1. (2004). A new set of magnetic field derivatives for mapping mineral prospects. doi
  2. (1995). A review of detailed airborne geophysical surveys in Great Britain, Mineral Reconaissance Programme Report, British Geological Survey,
  3. (1989). A terracing operator for physical property mapping with potential field data, doi
  4. (1968). Aeromagnetic anomalies related to remnant magnetization in volcanic rock,
  5. (1986). Approximating edges of source bodies from magnetic or gravity anomalies,
  6. (1998). Colour Shaded Relief Magnetic Anomaly Map of Britain, Ireland and adjacent
  7. (2002). Comparison of airborne and marine magnetic data in Donegal Basin, Ireland. The Leading Edge,
  8. (2008). Edge enhancement of potential-field data using normalized statistics, doi
  9. (2006). Enhancing potential field data using filters based on the local phase,
  10. (2009). Geophysics of Northern Ireland: the Tellus effect,
  11. (2010). HiRes airborne geophysical survey of Anglesey: a key dataset for unravelling complex geology and establishing an environmental baseline,
  12. (2003). Manual approaches to the removal of cultural noise from high-resolution aeromagnetic data acquired over highly developed areas, doi
  13. (1996). Palaeogene dyke swarm, NW Wales: evidence for Cenozoic sinistral fault movement,
  14. (1995). Potential Theory in Gravity and Magnetic Applications,
  15. (2009). Terracing potential field data, doi
  16. (1987). The age of blueschist metamorphism in Anglesey, North Wales: evidence from 40Ar/39Ar mineral dates of the Penmynydd schists. doi
  17. (2008). The Cleveland Dyke in southern Scotland, doi
  18. (2009). The HiRES airborne geophysical survey of Anglesey: Logistics Report, British Geological Survey

To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request.