GeoIndex help | Geophysics map theme

View the geophysics map theme

Click on the links below for further information about the available datasets.

Overview

These data-sets relate to measurements of the various geophysical properties of rocks. They aid mineral exploration, and in conjunction with other data-sets, are fundamental to our understanding of the UK's subsurface and 'deep' geology.

For more information on the geophysical datasets available from BGS, please see the digital products pages.

UKOGL Exploration Seismic Data

Exploration seismic data coverage provided by the UK Onshore Geophysical Library.

UKOGL provides a fully reconciled archive of:

  • Digital field data demultiplexed to SEG-Y format
  • Supporting observers reports and associated acquisition documents as digital scans
  • Line location data in UKOOA format
  • Processed digital stacks / migrations in SEG-Y format
  • Hard copy stack / migrated sections

UK Onshore Geophysical Library
Tel: 020 8780 2634
email: contact@ukogl.org.uk
Web: www.ukogl.org.uk
Contacts: Neil Anderton / Mark Alldred

Coal Authority Digital Geophysical Logs

The map shows the location and names of boreholes with digital geophysical logs acquired by the former National Coal Board and British Coal during their exploration for coal in the UK.

Ownership of UK coal exploration data was transferred to the Coal Authority (CA) following privatisation of the UK coal industry. The CA have appointed the British Geological Survey as custodian of this important national geological data archive. These data are in general publicly available; however, access to data within active mining licences is restricted in that it requires the consent of the mining licensee.

The CA data archive includes digital data for some of the geophysical borehole logging. These are mainly in the form of original field tapes; however, also available are some data transcribed onto more modern media during BGS projects.

The BGS will be pleased to provide information on data availability for named boreholes or within specified geographic areas, together with cost estimates and options for supplying copies. In the first instance please contact BGS Enquiries (enquiries@bgs.ac.uk) or go to the Enquiries section of the BGS web site, www.bgs.ac.uk

Coal Authority Seismic Data

The map shows the location and line-identifiers of reflection seismic profiles acquired by the former National Coal Board and British Coal during their exploration for coal in the UK.

Ownership of UK coal exploration data was transferred to the Coal Authority (CA) following privatisation of the UK coal industry. The CA have appointed the British Geological Survey as custodian of this important national geological data archive. These data are in general publicly available; however, access to data within active mining licences is restricted in that it requires the consent of the mining licensee.

The CA data archive includes hardcopy and digital data for the reflection seismic profiles, such as film and paper prints, original field tapes, demultiplexed data, processed stacked data, navigation (location) data and observers' and surveyors' acquisition reports. But please note that not all data types are available for all profiles.

The BGS will be pleased to provide information on data availability for named profiles or within specified geographic areas, together with cost estimates and options for supplying copies.

In the first instance please contact BGS Enquiries (enquiries@bgs.ac.uk) or go to the Enquiries section of the BGS web site, www.bgs.ac.uk.

Gravity readings

Land gravity

Regional gravity observations on the UK mainland, Northern Ireland, offshore islands, tidal estuaries and seabed. Most of the surveys were carried out by the BGS but the database includes data originally acquired by other organisations and subsequently given to the BGS to be managed as part of the national archive. Complete coverage of the UK mainland with a station density of 1-2 stations per square kilometre. The dataset for Great Britain is now available for free download.

Marine gravity

Unadjusted ship gravity, magnetic and bathymetry data acquired by BGS as part of its Offshore Reconnaisance Mapping Programme. This programme commenced in 1967, and was funded mainly by the Department of Energy. Unadjusted ship gravity and bathymetry data from various commercial and academic surveys between 1965 and 1994. Confidential M.O.D Hydrographic Office integrated ship gravity and magnetics surveys of NW Europe marine areas for which BGS acts as agent. Network adjusted gravity and magnetic compilations of data from BGS and non-BGS sources. Information on licensing costs.

High-resolution airborne surveys

The high-resolution airborne surveys shown on GeoIndex are classed as those flown with low terrain clearance (typically below 200m) and flight line spacing of less than 300m. The surveys were flown with various combinations of magnetic, radiometric and EM techniques, and include:

  • Surveys flown for the DTI mineral reconnaissance programme
  • Commercial surveys flown for mineral exploration and subsequently donated to the BGS
  • Surveys flown for the BGS for research and other purposes

Many of the datasets were originally recorded in analogue form, but the largest and those of most interest have been digitised. Please e-mail enquiries@bgs.ac.uk to enquire for information about availability and costs.

Regional airborne magnetic survey areas and flight lines

The surveys include:

  • Analogue airborne magnetic surveys of Great Britain for the Geological Survey (GSGB), which was subsequently digitised.
  • Commercial analogue survey of North Sea by Aeroservices Inc, subsequently digitised by BGS.
  • Commercial digital (+ one analogue) surveys off NW/N/NE of Britain by Huntings Geology and Geophysics, purchased outright by BGS.
  • Local surveys, digital and analogue aeromagnetic (+ other methods) surveys for BGS and commercial companies.

The survey covering Great Britain is now available for free download.

Local geophysical surveys lines and points.

The database contains an index to over 600 ground geophysical surveys carried out in the UK for a variety of projects. A large number of these surveys were done in conjunction with the DTI Mineral Reconnaissance Programme in the 1970's and 80's, and many others were carried out at the request of BGS field mapping groups. Information held describes the survey objective, location of measurements, geophysical methods and equipment used, reports and publications, storage locations of data and results (for analogue and digital data), dates and personnel. There are three data-sets; one showing the outline of the survey areas, another showing the actual survey lines within each area and another showing the survey points.

Magnetic anomalies

This low-resolution image has been produced from BGS airborne and marine magnetic data. The colour was generated using the BGS COLMAP software package. Colour levels are defined by histogram equalisation. Combining this image with the grey shaded relief image produces a similar image to the colour shaded relief image.

A published coloured shaded relief map, using the full resolution of the data and produced at a scale of 1:1 500 000, is available. Click here for further details. The map covers a larger area than this image, and includes additional data from other sources.

The data used to compile this image are available in various forms for academic and commercial licencing.

DATA PROCESSING
The data from surveys covering the UK mainland have been digitised from their original analogue form. Elsewhere data were acquired digitally. Standard methods of processing were used to remove diurnal and secular variations and to minimise line intersection errors. While efforts have been made to remove artefacts from the data, some may remain between adjacent datasets. Generally anomalies over man-made structures have not been removed.

The data have been interpolated onto a 1km x 1km grid using a variable tension technique, and smoothed.

REFERENCE FIELDS
Total field magnetic anomalies are referred to a variant of the International Geomagnetic Reference Field 1990 (IGRF90). In order to achieve an acceptable fit between adjacent surveys a correction was applied to IGRF90 for epochs prior to 1970, taking account magnetic observatory values.

Gravity anomalies

This low-resolution image has been produced from BGS land and marine gravity data. The colour was generated using the BGS COLMAP software package. Colour levels are defined by histogram equalisation. Combining this image with the grey shaded relief image produces a similar image to the colour shaded relief image.

A published coloured shaded relief map, using the full resolution of the data and produced at a scale of 1: 1500 000, is available priced at £4.95. Click here for further details. The map covers a larger area than this image, and includes additional data from other sources.

The data used to compile this image are available in various forms for academic and commercial licencing.

The measured gravity values have been corrected in order to show the anomalies attributable to variations in crustal density. In broad terms the blues are attributable to large volumes of low density rocks, the reds to high density rocks. Significant lows occur, for instance, over areas of thick, low density sedimentary rocks(e.g. Cheshire Basin, Wessex Basin), or large granites (eg Cornwall).

BGS provide two commercial services for accurately determining site specific values of g usually used by engineering laboratories doing weight drop tests etc. where an accurate value of gravity is required. For less accurate applications a value can also be calculated.

Marine data. Free-air anomalies have been calculated from observed gravity values along marine survey lines. Line intersection errors between crossing lines and overlapping surveys have been used using network adjustment techniques. Free air anomalies have been calculated for sea-bottom stations.

Land data. Bouguer anomalies have been calculated from gravity observations at points of known height. In order to minimise the effect of topography, Bouguer corrections for the British Mainland have been applied using a density estimated for each station. Elsewhere a correction density of 2.67 Mg/m3 has been used. Corrections for the gravitational effect of terrain have been made where significant, and in a general extent to a radius of 48.6km.

The data have been interpolated onto a 1km x 1km grid using a variable tension technique, and smoothed.

Superficial deposits 1:625 000 scale

The 'Superficial deposits' shown on the GeoIndex map includes the youngest geological deposits laid down in England and Wales, Scotland and part of Northern Ireland. This map is based on the first edition Drift 1:625 000 scale Geological Map of the United Kingdom published in 1977 as two sheets, North and South, available from the BGS Internet Shop.

The Superficial deposits, mainly formed in the Quaternary period of geological time, which extends from the present back to 2 million years ago. Many of the deposits were formed during episodes of glaciation ,or deposited by rivers. They occur as discontinuous patches and larger spreads and rest on top of the older rocks (referred to in the Bedrock).

Most of these Superficial deposits are unconsolidated sediments such as gravel, sand, silt and clay. The name of each deposit or group of deposits corresponds to that shown on the published 1:625 000 map e.g. River Terrace Deposits.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1977. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Faults 1:625 000 scale

Digital geological dataset depicting the faults only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Dykes 1:625 000 scale

Digital geological dataset depicting the dykes only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Bedrock 1:625 000 scale

The 'bedrock' shown on the GeoIndex map comprises the bedrock geology, which represents the outcrops (at surface) and subcrops (at near-surface, beneath superficial deposits) in England and Wales, Scotland and part of Northern Ireland. It is based on the third edition Solid 1:625 000 scale Geological Map of the United Kingdom published in 1979 as two sheets, North and South. These sheets are available from the BGS Internet Shop.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276