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| Titel |
Did Adria rotate relative to Africa? |
| VerfasserIn |
D. J. J. van Hinsbergen, M. Mensink, C. G. Langereis, M. Maffione, L. Spalluto, M. Tropeano, L. Sabato |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1869-9510
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| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 2 ; Nr. 5, no. 2 (2014-07-02), S.611-629 |
| Datensatznummer |
250115312
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| Publikation (Nr.) |
 copernicus.org/se-5-611-2014.pdf |
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| Zusammenfassung |
| The first and foremost boundary condition for kinematic reconstructions of
the Mediterranean region is the relative motion between Africa and Eurasia,
constrained through reconstructions of the Atlantic Ocean. The Adria
continental block is in a downgoing plate position relative to the strongly
curved central Mediterranean subduction-related orogens, and forms the
foreland of the Apennines, Alps, Dinarides, and Albanides–Hellenides. It is
connected to the African plate through the Ionian Basin, likely with Lower
Mesozoic oceanic lithosphere. If the relative motion of Adria versus Africa
is known, its position relative to Eurasia can be constrained through a plate
circuit, thus allowing robust boundary conditions for the reconstruction of
the complex kinematic history of the Mediterranean region. Based on kinematic
reconstructions for the Neogene motion of Adria versus Africa, as interpreted
from the Alps and from Ionian Basin and its surrounding areas, it has been
suggested that Adria underwent counterclockwise (ccw) vertical axis rotations
ranging from ~ 0 to 20°. Here, we provide six new paleomagnetic
poles from Adria, derived from the Lower Cretaceous to Upper Miocene
carbonatic units of the Apulian peninsula (southern Italy). These, in
combination with published poles from the Po Plain (Italy), the Istrian
peninsula (Croatia), and the Gargano promontory (Italy), document a
post-Eocene 9.8 ± 9.5° counterclockwise vertical axis rotation
of Adria. Our results do not show evidence of significant Africa–Adria
rotation between the Early Cretaceous and Eocene. Models based on
reconstructions of the Alps, invoking 17° ccw rotation, and based on
the Ionian Basin, invoking 2° ccw rotation, are both permitted within
the documented rotation range, yet are mutually exclusive. This apparent
enigma could possibly be solved only if one or more of the following
conditions are satisfied: (i) Neogene shortening in the western Alps has been
significantly underestimated (by as much as 150 km); (ii) Neogene extension
in the Ionian Basin has been significantly underestimated (by as much as
420 km); and/or (iii) a major sinistral strike-slip zone has decoupled
northern and southern Adria in Neogene time. Here we present five alternative
reconstructions of Adria at 20 Ma, highlighting the kinematic uncertainties,
and satisfying the inferred rotation pattern from this study and/or from
previously proposed kinematic reconstructions. |
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