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The geological interpretation of gravity and magnetic surveys over the exposed southern margin of the Galway Granite, Ireland
Author(s) -
Fairhead J. D.,
Walker P.
Publication year - 1977
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3350120102
Subject(s) - geology , bouguer anomaly , magnetic anomaly , margin (machine learning) , gravity anomaly , geochemistry , geomorphology , seismology , paleontology , machine learning , oil field , computer science
Gravity measurements across the southern margin of the Galway granite, on the Islands of Gorumna and Lettermullen, reveal small positive Bouguer anomalies of amplitudes less than 40 g.u. associated with the denser country rock. These anomalies suggest that the ‘country rock’ is no more than a thin wedge, thickening southwards. Such a structure may form part of a large roof pendant or roof section with the true granite margin lying further south. Magnetic anomaly profiles across the granite contact reveal that the rock groups, making up the country rock, have distinct magnetic character which may provide a means of mapping their southern extent beneath Galway Bay.