Paleomagnetism of Aptian-Albian sections from the Northern Apennines (Italy): Implications for the 150-100 Ma apparent polar wander of Adria and Africa | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Paleomagnetism of Aptian-Albian sections from the Northern Apennines (Italy): Implications for the 150-100 Ma apparent polar wander of Adria and Africa

Type de publication:

Journal Article

Source:

Earth and Planetary Science Letters, Volume 276, Ticket 1-2, p.115-128 (2008)

ISBN:

0012-821X

Numéro d'accès:

ISI:000261679200012

Mots-clés:

UMR 7154 ; Paléomagnétisme ; N° Contribution : 2415

Résumé:

We computed a new 120 to 100 Ma high-resolution Apparent Polar Wander Path (APWP) for Adria from magnetostratigraphic studies in the Northern Apennines (Italy). We analyzed 274 cores from three Early Aptian-Late Albian sections of the Marne a Fucoidi Fm., belonging to the sedimentary succession deposited above the Adria passive margin during Meso-Cenozoic time. To solve the problem of tectonic rotations induced during the Apennine orogenesis, we computed relative rotations between sections and realigned them into a common declination reference frame (Bosso, Italy). These new data were added to the previous 150-125 Ma segment computed from the same region [Satolli, S., Besse, J.. Speranza, F., Calamita, F., 2007. New 125-150 Ma high-resolution Apparent Polar Wander Path for Adria from magnetostratigraphic sections in Umbria-Marche (Northern Apennines. Italy): Timing and duration of the global Jurassic-Cretaceous hairpin turn. Earth Planet. Sci. Lett. 257, 329-342. doi:10.1016/j.epsl.2007.03.009.] to get a very high-resolution 100 to 150 Ma APWP for Adria. The comparison of our APWP with the African APWP segment of Besse and Courtillot computed with 10 Myr sliding window [Besse. J., Courtillot. V., 2002. Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr. J. Geophys. Res. 107. doi:10.1029/2000JB000050.] leads to the following conclusions: 1) our segment (after a 25 clockwise rotation of the Bosso reference frame) is in very good agreement with the African APWP, as shown by a very similar time evolution of inclinations and declinations, most often statistically indistinct; 2) this agreement vindicates our previous model of structural unit rotation for older periods [Satolli, S., Besse, J., Speranza, F., Calamita, F., 2007. New 125-150 Ma high-resolution Apparent Polar Wander Path for Adria from magnetostratigraphic sections in Umbria-Marche (Northern Apennines, Italy): Timing and duration of the global Jurassic-Cretaceous hairpin turn. Earth Planet. Sci. Lett. 257, 329-342. dot:10.1016/j.epsl.2007.03.009.] 3) the concept of "synthetic" APWP construction is strongly validated; 4) the good agreement found strengthens the fact that Adria has been a promontory of Africa at the lithospheric level during Late Jurassic-Early Cretaceous (150-100 Ma), affected by tectonic rotations linked to the Apennines orogenic phases during Neogene; 5) our data evidence a possible ca. 105 Ma southward motion of Adria undetected from classical African APWPs. Finally, we have not found evidence for reversals interrupting the long normal Cretaceous superchron in our sections. (C) 2008 Elsevier B.V. All rights reserved.

Notes:

Satolli, Sara Besse, Lean Calamita, Fernando