Rock magnetic properties of basalt lithologies and subsurface modeling from magnetic field data for the Reykjanes peninsula (Iceland)

Dietze, Frank; Kontny, Agnes; Heyde, Ingo; Vahle, C.


Different stratigraphic and lithologic basalt units of the Reykjanes peninsula (SW-Iceland), where the submarine Reykjanes Ridge passes over into the rift zone of southwestern Iceland, were studied with respect to their rock magnetic properties. The less than 11500 years old basaltic fissure eruptions show a relative high natural remanent magnetization, NRM, (average: 17.5 Aim)and high Koenigsberg values (65.8) indicating a clear dominance of the natural remanent magnetization compared to the induced part of the magnetization. The geomagnetic field was measured relative to the regional field at Reykjanes peninsula along three profiles normal to the mid-Atlantic spreading axis. These measurements along with the rock magnetic data and field observations were used for modeling the geological subsurface of the Reykjanes peninsula. The model suggests a potentially complex network of shallow dykes in the subsurfaceof this area, which we interpret as source of the positive as well as negative short wavelengthanomalies.