A significant part of this data collection is geophysical survey data in digital form, being mainly instrumental recordings made during fieldwork. Derived data created during the subsequent processing and interpretation of the field data is described in 'Nirex Magnetic Tape Archives - Processed Data'. These data were originally stored on a variety of media. With the overall aim of delivering an efficient and effective archive service, the data have been consolidated onto DLT cartridges. Some related data, which were either analogue, on obscure media or in unknown formats have been retained in their original form. British Geological Survey maintains a full catalogue of the data, as an Access database.The data sets that comprise the magnetic archive are the following: Seismic surveys: marine, land and transition zone; field, navigation, statiatcs; Geophysical wireline logging of boreholes: routine wireline logging of investigation boreholes (gamma-ray, sonic, porosity, etc.); velocity surveys; dipmeter surveys;vertical seismic profiling; borehole televiewer (BHTV) surveys; formation microscanner (FMS) surveys; Ground surveys: magnetic; gravity; radiometric; thermal imaging; photographic imaging; in-flight videos. The ownership of NIREX (Nuclear Industry Radioactive Waste Executive) was transferred from the nuclear industry to the UK Government departments DEFRA and DTI in April 2005, and then to the UK's Nuclear Decommissioning Authority (NDA) in November 2006.
