A total-field magnetic anomaly map of the Reykjanes peninsula, Southwest Iceland

Aeromagnetic surveys of the Reykjanes peninsula in Southwest Iceland were carried out in 1965 and 1968. They revealed the presence of positive magnetic anomalies in the southern and central parts of the peninsula, whereas a broad negative anomaly followed its northern coast. These variations were caused only to a small extent by the local topography. A map of SW-NE trending fissure swarms in the peninsula, published in 1978, indicated that they were correlated with the positive anomalies as well as with centers of recent volcanism and high-temperature geothermal activity. Processing of the results from the 1968 survey combined with further surveys in 1973, 1985–1986 and 1991–1992 has resulted in a new multicolor map of field residuals in the Reykjanes peninsula and its surroundings. The most prominent feature in the map is lineations of positive anomalies partially overlapping with the volcanic fissure swarms. Susceptibility measurements on drill cuttings indicate that their sources may reach to more than 1.5 km depth.