HR: 16:30h
AN: GP54A-03    [Abstracts]
TI: The rotation of Iberia during the Aptian and the opening of the Bay of Biscay
AU: * Gong, Z
EM: gong@geo.uu.nl
AU: Langereis, C
EM: langer@geo.uu.nl
AU: Dekkers, M
EM: dekkers@geo.uu.nl
AU: Mullender, T
EM: mullende@geo.uu.nl
AB: We present paleomagnetic results of lower Cretaceous limestone and marl sequences from the Organyà Basin (Southern Pyrenees, Spain), 42 sites (810 samples), ranging in age from 125 Ma to 92.5 Ma (lowermost Aptian to Cenomanian). Positive fold tests prove a primary (pre-folding) origin of the NRM. The characteristic remanent magnetization (ChRM) direction of the lowermost Aptian limestones is 309°/55° ± 1.6° (α₉₅) (N = 112). The marl formations from the lower and middle Aptian have a ChRM declination of 334°±1.4° and an inclination of 53°±1.4° (N = 282). Upper Aptian marls & limestones show a declination of 345°±1.3° and inclination of 53°±1.3° (N = 177). The rotation is ~40° anticlockwise with respect to Eurasia and occured during the Aptian (125- 112 Ma). The Albian and Cenomanian sites all have similar directions, on average 356°/48°±2.2° (N = 239) and fit the apparent polar wander path of Eurasia. This indicates that the rotation of Iberia was completed before the Albian. The rotation of Iberia is now firmly constrained to the Aptian and its relation to other regional tectonic events will be discussed, including the evolution of the Bay of Biscay.
DE: 1525 Paleomagnetism applied to tectonics: regional, global
DE: 1527 Paleomagnetism applied to geologic processes
SC: Geomagnetism and Paleomagnetism [GP]
MN: 2007 Fall Meeting