Detailed paleomagnetic study of two volcanic polarity transitions recorded in eastern Iceland

• Published in: Physics of the earth and planetary interiors 1999-09, Vol.115 (2), p.119-135
• Main Authors: Herrero-Bervera, Emilio, Walker, George P.L, Harrison, Christopher G.A, Garcia, Jose Guerrero, Kristjansson, Leo
• Format: Article
• Language: English
• Subjects: Iceland; Paleomagnetism; Virtual geomagnetic pole
• ISSN: 0031-9201; 1872-7395
• DOI: 10.1016/S0031-9201(99)00074-6

Two sequences of 45 and 49 individual lava flows respectively have been sampled in eastern Iceland. The two sections range in age from 12.09 to 10.21 Ma as reported by Watkins and Walker [Watkins, N., Walker, G.P.L., 1977. Magnetostratigraphy of eastern Iceland. Am. J. Sci. 277, 513–584.] and are labelled as profiles C and D. Stepwise alternating field (AF) and thermal demagnetizations accompanied by investigations of rock magnetic properties indicate that the magnetization is primarily carried by titanomagnetite. Demagnetization experiments have identified eight and six transitional lavas, respectively, for these profiles. The transitional virtual geomagnetic poles (VGPs) of the (R-N) profile C reversal are located mainly between Patagonia and Antarctica with a tendency of the virtual poles to move towards west coast of South America, subsequently traveling to the northern hemisphere through several discrete steps located in the middle part of South America, then to west Africa and on to central Asia before the poles settle into normal polarity. The second and younger VGP path corresponding to profile D is a path characterized by a reverse-to-normal-to-reverse (R-N-R) motion of the virtual poles. This path is characterized by poles located in west Antarctica, Patagonia and the western and eastern part of South America. The passage from the southern to the northern hemisphere is also through a discrete sets of steps along the southwestern Pacific followed by a rapid motion to the northern Siberian region, continuing to the western equatorial part of South America before moving on to the central region of Asia, followed by a motion to the western Pacific prior to the final move to the eastern part of Antarctica. The data from eastern Iceland based on highly reliable transitional results, as indicated by the demagnetizations and rock magnetic experiments derived from relatively spaced sites and different ages, seem to indicate that the eastern Icelandic high latitude (66°N) profiles studied have several persistent transitional paleofield features that are uniquely observed at those sites particularly when compared to other volcanic records located at lower latitudes.