Palaeomagnetism of Ten Lava Sequences from South-Western Iceland

Abstract

This paper concerns palaeomagnetic studies of 10 lava sequences in southwestern Iceland. The sequences contain 329 lavas. Specimens which have been A.F. demagnetized provide palaeomagnetic polarities which agree very well with Tr. Einarsson's earlier compass studies of the same sequences in the field. Little new information is provided about the stratigraphic correlations among the various sequences investigated. Interpretation still depends essentially on Einarsson's original field mapping.Mean N and R pole positions are not significantly different, but are both on that side of the geographic pole far from Iceland, which conforms with the world-wide pattern recently emerging.Three transition zones provide new evidence about the behaviour of the geomagnetic field during inversion of polarity. Sub-

The R3-N3 and R5-N5 Palaeomagnetic Transition Zones in SW-Iceland Revisited.

“…We confirm the observation by WILSON et al (1972) that a complex pole path is recorded during the R5-N5 transition. The N4-R3 path, for which we have less reliable data, also seems to yield transitional poles with widely varying longitudes.…”

“…Presumably the same boundary was sampled by WILSON et al (1972) Although the magnetic stability of the samples from the last two groups of lavas was not ideal, they indicate that there was much irregular movement of the virtual pole at or close to the Gauss-Matuyama boundary (Fig. 5).…”

“…Geological information on the R3-N3 sampling sites was not reported in Einarsson's or Sigurgeirsson's publications. WILSON et al (1972) sampled in several of the R3-N3 profiles for palaeointensity measurements; however, his paper only presents pole positions and no detailed information on locations or stratigraphy. Profiles F and G of Sigurgeirsson's were resampled by KRISTJANSSON et al (1980), who used portable drills for collecting.…”

“…The R5-N5 Transition WILSON et al (1972) show a map of pole positions from several lavas having "anomalous" remanence directions in their profile C, in the Villingadalur corrie of mt. Skardsheidi at 64'30'N, 21 °34' W, just north of our Fig.…”

Paleosecular Variation of Direction and Intensity from Two Pliocene-Pleistocene Lava Sections in Southwestern Iceland.

“…(1988) of Brunhes chron age and section K of Wilson et al (1972) of early Matuyama chron age. Paleodirections obtained from 22 laves at the former section do not seem to have averaged out the secular variation completely because of their small angular standard deviation, and this suggests rapid accumulation of the lavas.…”