Magnetostratigraphy of Early-Middle Toarcian expanded sections from the Iberian Range (central Spain)

作者：Osete Maria Luisa^*; Gialanella Paola Romana; Gomez Juan J; Villalain Juan J; Goy Antonio; Heller Friedrich

来源：Earth and Planetary Science Letters, 2007, 259(3-4): 319-332.

DOI：10.1016/j.epsl.2007.04.048

• magnetostratigraphy
• Early Jurassic
• biostratigraphy
• Iberian Plate

The magnetostratigraphy of the Lower-Middle Toarcian has been established in two well-dated strati graphically expanded sections: the Sierra Palomera and the Arino 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 degrees C/475 degrees C (A component) and a high temperature unblocking component up to 575 degrees 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 degrees, Plon=241.3 degrees E (dm=5.4 degrees dp=6.0 degrees).
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.

• 出版日期2007-7-30