Record details

Title
    Palaeomagnetism in the Sines massif (SW Iberia) revisited: evidences for Late Cretaceous hydrothermal alteration and associated partial remagnetization
Author
    Henry, B.
    Kratinová, Zuzana
    Marques, F. O.
    Moita, P.
    Ribeiro, P.
    Silva, P. F.
Language
    anglicky
Publication type
    článek v odborném periodiku
Source title - serial
    Geophysical Journal International
Vol./nr.
    Roč. 195, č. 1
Pages
    s. 176-191
Year
    2013
Notes
    Projekt: PTDC/CTE-GIX/098696/2008, FCT, PT3cav_un_auth*0302127
    Rozsah: 16 s. : P
Subject category
    magnetic fabrics and anisotropy
    magnetic mineralogy and petrology
    palaeomagnetism applied to tectonics
Keyword
    Alteration
    Associated
    Cretaceous
    Evidences
    Hydrothermal
    Iberia
    Late
    Massif
    Palaeomagnetism
    Partial
    Remagnetization
    Revisited
    Sines
    SW
Abstract (in english)
   This study revisits the palaeomagnetism of the Sines massif in the southwestern Iberian Margin (Portugal). The palaeomagnetic analysis was complemented by a comprehensive study of the magnetic mineralogy by means of rock magnetic measurements and petrographic observations. The overall dispersion of palaeomagnetic directions and their migration observed during stepwise demagnetizations have revealed the superposition of remanence components. We interpret this complex palaeomagnetic behaviour as related to the regional hydrothermalism associated with the last stages of Late Cretaceous magmatic activity. This environment favoured mineralogical alteration and a partial chemical remagnetization, giving in most samples a composite magnetization, which has been erroneously interpreted as the primary one in a previous study, then leading to a questionable model for Cretaceous Iberia rotation. Nonetheless, for some samples a single component has been isolated.
   Interesting rock magnetic properties and microscopic observations point to a well-preserved magnetic mineralogy for these samples, with magnetite clearly of primary origin.
Contributor
    AV ČR Brno, Geofyzikální ústav
Contributor code
    AV ČR, GFÚ
Source format
    U
Import date
    23. 10. 2014