کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4680308 | 1634916 | 2007 | 14 صفحه PDF | دانلود رایگان |
The magnetostratigraphy of the Lower–Middle Toarcian has been established in two well-dated stratigraphically expanded sections: the Sierra Palomera and the Ariño sections, located in the Iberian Range, in central-eastern Spain. Two magnetisation components could be isolated by thermal cleaning: a secondary syntectonic component of always normal polarity unblocking at intermediate temperatures up to 450 °C/475 °C (A component) and a high temperature unblocking component up to 575 °C (B component). The B component passes fold and reversal tests and is considered the characteristic remanent magnetisation of primary origin. The first Toarcian palaeomagnetic pole for Iberia has been obtained: Plat = 77.4°, Plon = 241.3°E (dm = 5.4° dp = 6.0°).Five pairs of normal and reversed polarity zones were calibrated to regional ammonite subzones. The pattern can be calibrated to other Toarcian magnetostratigraphic studies, but provides a more detailed biostratigraphic framework. A refined magnetic polarity time scale is proposed for the Lower–Middle Toarcian.
Journal: Earth and Planetary Science Letters - Volume 259, Issues 3–4, 30 July 2007, Pages 319–332