Palaeomagnetic studies of Icelandic lava flows,Geophys
This paper describes a palaeomagnetic investigation of 107 igneous bodies, mostly basaltic lavas, of Pliocene and Pleistocene age in Iceland. A variety of conclusions has resulted from the study. Palaeomagnetic directions in lavas erupted in 1729, 1783 and 1875 do not support the postulated ' c...
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| Format: | Text |
| Language: | English |
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1972
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1029.6073 http://gji.oxfordjournals.org/content/26/5/459.full.pdf |
| Summary: | This paper describes a palaeomagnetic investigation of 107 igneous bodies, mostly basaltic lavas, of Pliocene and Pleistocene age in Iceland. A variety of conclusions has resulted from the study. Palaeomagnetic directions in lavas erupted in 1729, 1783 and 1875 do not support the postulated ' cycloid ' path for the Icelandic geomagnetic pole. Data are given for an application of geomagnetic reversal stratigraphy showing that Bering Strait opened more than 3 My ago, allowing Pacific boreal mollusks to enter Icelandic waters; these data also suggest that there were at least nine extensive glaciations since a time over 2 My ago. Lava flows erupted on Snaefellsnes Peninsula, western Iceland, contain large amounts of viscous remanent magnetization; partial demagnetization studies reveal a pre-dominant reversed polarity for most of these lavas with one pronounced ' excursion ' of virtual geomagnetic poles to very low latitudes. Detailed studies of a dike cutting a lava flow show that the lava's remanence is unaffected beyond one dike width from the dike contacts. Brunhes epoch paleosecular variation is consistent with a model combining a changing nondipole field like the present one with a dipole wobble of about 11". 1. |
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