Magnetic structural information obtained from the HiRES airborne survey of the Isle of Wight

Abstract

This study summarises the structural information obtained from a modern high resolution magnetic survey over the Isle of Wight corroborated with additional information derived from existing data available over a much wider area. This new, low-altitude, survey offered the opportunity to compare the UK national baseline magnetic data set (GSGB) acquired during the late 1950s and early 1960s with a high resolution airborne geophysical survey (HiRES) data set. The low level modern survey data, covering an unusually small area for an airborne magnetic investigation, has not been systematically de-cultured for non-geological perturbations since the extent of the cultural interference made the task non-viable. However, after spectral filtering of the two data sets, a West to East trending arcuated magnetic basement feature is successfully defined and compared. Depth estimates for this basement feature are proposed and considered alongside previous estimates which placed the causative body at greater depth.Onshore, the low gradient magnetic field, with little significant shallow magnetic structure within a thick succession of sedimentary rocks, is subjected to a range of filtering techniques that permit a preliminary interpretation of lineaments within the succession. This line work is considered in conjunction with the regional fault mapping undertaken as part of a seismic re-interpretation.

Levelling aeromagnetic survey data without the need for tie‐lines

“…Levelling problems were observed in both data sets, most significantly with the nose data presented here, and White, Beamish, and Cuss (2009) described the processing in detail. White and Beamish (2011) then used the final levelled magnetic data to classify the magnetic structural information contained within a high-resolution airborne survey. The region was of particular interest since the thick and relatively young, sedimentary succession displayed little significant shallow magnetic structure pushing the limits of the achievable resolution.…”

“…The levelled data were used alongside the U.K. national baseline magnetic survey data set acquired in the late 1950s and early 1960s to compare the data content in modern and previous generation aeromagnetic surveys (Beamish and White 2011). Figure 3 shows the developments made during the processing sequence with pre-levelled data shown in Fig.…”

“…Continuous N-S trending anomalies linked to poorly levelled line data are observed in the gridded AS. The levelled data are much cleaner and ready for further interpretation procedures (see Beamish and White 2011). The final data set considered here is the Tellus Border survey, an EU INTERREG IV-funded regional mapping project, flown over the border counties of the Republic of Ireland, adjacent to Northern Ireland.…”

“…This paper is published with the permission of the Executive Director, British Geological Survey (NERC). Beamish D. and White J.C. 2011. Aeromagnetic data in the UK: a study of the information content of baseline and modern surveys…”

A lithological assessment of the resistivity data acquired during the airborne geophysical survey of Anglesey, North Wales

“…Throughout the last decade, a series of multi-parameter airborne geophysical surveys have been undertaken in the UK (Peart el at., 2003;Beamish & Young, 2009;Beamish & White, 2011a;White & Beamish, 2011). The surveys acquired electromagnetic, radiometric (gamma-ray spectroscopy) and magnetic data at low altitude, and with a line-spacing of 200 m. These High Resolution Airborne Resource and Environmental (HiRES) surveys have demonstrated the high levels of precision achievable with airborne data.…”