Abstract
A regional survey of the southern Reykjanes Ridge (52°N to 57°N) shows an irregular topography: a rift valley which is only partly recognizable as such, with varying azimuth and some fracturezone-like interruptions. The survey also comprised gravity and magnetic measurements.
The course of the axis as well as the perpendicular fractures show up well in the free air anomalies as relative troughs within an area of positive free air gravity (Figure 5). There is no indication of density variations within the topographic masses.
The anomaly pattern of total magnetic intensity indicates the exact position of the rift axis and a bifurcation at about 55°N. From the parallel magnetic anomalies south of 55°N (Figure 2) a spreading rate can be deduced of 1.10 cm/yr perpendicular to the rift axis (Figure 3). This spreading rate is at the same time the plate movement involved.
A survey of the Iceland-Faeroe Ridge with a 3–5 miles grid shows large gravity and magnetic anomalies over a smooth topography, indicating large pockets of light material, probably of volcanic origin. These areas have normal magnetization. Positive gravity anomalies forming a ring structure along the 200 m isobath are characterized by reversed magnetization.
The dissimilarity in morphology, seismicity and inner structure between the two ridges that intersect in Iceland suggest that there is no relation between the two phenomena.
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Fleischer, U. Gravity surveys over the Reykjanes Ridge and between Iceland and the Faeroe Islands. Marine Geophysical Researches 1, 314–327 (1971). https://doi.org/10.1007/BF00338260
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DOI: https://doi.org/10.1007/BF00338260