MAGNETIC SURVEYS OF ICELAND

Data from a 1968-1980 aeromagnetic survey of Iceland and a 1972-1973 marine magnetic survey of a part of the shelf around Iceland have been digitized and upgraded. Additional aeromagnetic survey lines were flown in 1985-1986. After appropriate low-pass filtering and regridding, a new multicolor map of geomagnetic field intensity anomalies over the island and its surroundings was produced. The main features of the anomaly field are of two types: The first (a) comprises broad lineations subparallel to currently active or extinct spreading zones. These are believed to be mostly due to tilted basalt lava flows of alternating remanence polarity; in Quaternary regions, other extrusives, of subglacial origin, also contribute to the lineations. The second (b) comprises localized anomalies of the order of 10 km or less at individual volcanic centers. We describe some of these features in terms of current knowledge of the age, structure and magnetic properties of the uppermost crust in Iceland.