The Gallejaur intrusion in northern Sweden — a geophysical study

Abstract
Geophysical and geological models of the Gallejaur structure in northern Sweden are presented. The plausibility of each of them is discussed. It is shown that the models so far suggested, as interpreted mainly on the basis of geological mapping, are not compatible with petrophysical studies combined with gravity and magnetic data. An alternative model of the Gallejaur structure based on combined geological, petrophysical and geophysical interpretation is suggested. The structure is interpreted as a large rounded mafic laccolith intrusion with a shallow cap of monzonite derived by differentiation at the top. The maximum depth extent of the structure is calculated to be about 3.5 to 4.5 kilometres.