Secular variation and reversals in a composite 2.5 km thick lava section in central Western Iceland

Abstract

The direction and intensity of primary remanence has been measured in oriented specimens from 367 lava flows of Late Miocene age in Western Iceland. The lavas which were sampled in 8 overlapping profiles, were generally good material for paleomagnetic measurements. In a 2500-m composite section, at least 15 reversals of polarity and several excursions are recorded. The mean remanence direction and other overall paleomagnetic parameters for the present collection of lavas are similar to those found elsewhere in Iceland. The average rate of buildup of this lava pile was rather low and possibly episodic. Hence, correlations to the geomagnetic polarity time scale and to polarity patterns in other composite sections mapped in Iceland are not straightforward.

Stratigraphy and paleomagnetism of a 2.9-km composite lava section in Eyjafj�rdur, Northern Iceland: a reconnaissance study

“…4), indicating absence of more than one directionally distinct high-coercivity components. This behavior is also dominant in lavas from other surveys in Iceland (e.g., Kristjansson and Johannesson 1999 , Fig. 3).…”

“…Some of these lavas might be more appropriately named "flow units" or "compound flows" (cf. Watkins and Walker 1977;Kristjansson and Johannesson 1999). This serial correlation is quite common in the Miocene to Quaternary lava pile in Iceland (see Kristjansson et al 1980, Section 5.2;Kristjansson et al 2003).…”

Paleomagnetism and magnetic anomalies in Iceland

“…However, no In the stippled area, basement rocks are less than 0.8 Ma old, and we also indicate the position of the 10 Ma isochron (Saemundsson, 1986). The numbers refer to publications where the composite surveys are reported, as follows: (1) Watkins and Walker (1977); (2) Helgason (1982), Bleil et al (1982); (3) Kristjansson et al (1995); (4) McDougall et al (1976b) and Kristjansson and Gudmundsson (2005); (5) Helgason and Duncan (2001); (6) Saemundsson et al (1980); (7) Kristjansson et al (1992); (8) Kristjansson et al (2004); (9) Doell (1972), Kristjansson et al (1988), Eiriksson et al (1990); (10) McDougall et al (1984); (11) Kristjansson and Johannesson (1996); (12) Kristjansson et al (2003); (13) ; (14) Kristjansson and Johannesson (1999); (15) Kristjansson et al (1980); (16) Kristjansson et al (1991); (17) Kristjansson and Gudmundsson (2001). certain correlations between distant parts of the country, using e.g. particular geomagnetic epochs or extensive clastic horizons, have been found so far.…”

Dike intrusion as a possible cause of linear Martian magnetic anomalies

“…The result of these processes is to reduce the magnetizatioñ 3-6 A m -1 Johnson, 1991, 1993a;Smith and Banerjee, 1986). For comparison, a recent study of subaerial Icelandic basalts found a maximum magnetization of 16.2 A m -1 (Kristjansson and Johanesson, 1999).…”