Digital filtering of high sensitivity aeromagnetic data over the U.S. Atlantic continental margin and its application to regional tectonics

The U.S. Geological Survey contracted a high‐sensitivity, digital aeromagnetic survey that was flown over the U.S. Atlantic continental margin over a period of 15 months between 1974 and 1976. The 185,000 km of profile data have a relative accuracy approaching a few tenths of a nanotesla, which allowed compilation into maps at a scale of 1:250,000, with a contour interval of 2 nT. Automatic data processing using the Werner method allowed calculations of apparent depth to sources of the magnetic anomalies on all of the profiles, assuming a dike or interface as a source. Comparison of the computed depths to magnetic basement with multichannel seismic profiles across the survey area helped to reduce ambiguities in magnetic depth estimates and enabled interpolation of basement structures between seismic profiles. The resulting map showing depth to basement of the Atlantic continental margin is compatible with available multichannel seismic data, and we consider it a reasonable representation of the base of the sedimentary column.

Download Full-text

Project EASTMAR: acquisition of high sensitivity aeromagnetic data off East Greenland

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v100.7707 ◽

1980 ◽

Vol 100 ◽

pp. 91-94

Author(s):

H.C Larsen ◽

L Thorning

Keyword(s):

Continental Margin ◽

North Atlantic ◽

High Sensitivity ◽

Aeromagnetic Data ◽

Energy Agency ◽

Aeromagnetic Survey ◽

East Greenland ◽

Main Work ◽

Marine Gravity ◽

Multichannel Seismic Reflection

Project EASTMAR, an aeromagnetic survey of major parts of the continental margin off East Greenland, is an energy research project originally funded by the Danish government through the Energy Agency (Thorning, 1978; Larsen & Thorning, 1979). During 1979, the EASTMAR project has been included in an EEC supported geophysical project called the NAD project (North Atlantic D; see also Risum, this volume). The aim of the NAD project is to map the deep and regional structures of the continental margin off East Greenland by using high sensitivity aeromagnetic surveys, multichannel seismic reflection and marine gravity surveys, and to prepare a preIiminary assessment of the petroleum geology of the region. In 1979, the main work of EASTMAR has been the acquisition of new aeromagnetic data between latitudes 600 N and 800 N in accordance with the flight programme (fig. 31; and Larsen & Thorning, 1979) and compilation of existing aeromagnetic and seismic data (Larsen, 1980).

Download Full-text

Geophysical investigations offshore East Greenland - Project NAD

Rapport Grønlands Geologiske Undersøgelse ◽

10.34194/rapggu.v105.7755 ◽

1981 ◽

Vol 105 ◽

pp. 56-60

Author(s):

M.S Andersen ◽

H.C Larsen ◽

J.B Risum ◽

L Thorning

Keyword(s):

Continental Margin ◽

High Sensitivity ◽

Geophysical Data ◽

Aeromagnetic Data ◽

East Greenland ◽

Gravity And Magnetic ◽

Marine Gravity ◽

Geophysical Surveys ◽

Geophysical Investigations

The objective of project NAD is to map the continental margin of East Greenland, using high sensitivity aeromagnetic surveys and multichannel seismic refIection and marine gravity and magnetic surveys, and to prepare a preliminary petroleum geological assessment of the region on the basis of all the available data. The aeromagnetic surveys were carried out during 1979 (Larsen & Thorning, 1980). Marine geophysical surveys are planned for 1980, 1981 and 1982 (Risum, 1980). During 1980 a total of 2610 km of marine geophysical data were collected and the processing and interpretation of the aeromagnetic data acquired in 1979 was continued.

Download Full-text