|dc.description.abstract||The paleogeography and tectonic history of the Corsica-Sardinia Microplate
(CSM) and the opening of the Liguro-Provençal ocean since Oligocene times is
based on a wealth of geologic, geophysical, and paleomagnetic studies and
relatively well understood. From Neogene paleomagnetic data it is known that
the CSM rotated ~55° counterclockwise (CCW). Conversely, the paleogeography
of Sardinia and the surrounding regions during the Mesozoic is much less clear
due to the absence of paleomagnetic data, except for scarce studies on Triassic
and Jurassic sediments from Sardinia. These data indicate a ~90° CCW
rotational history of the microcontinent. So, between the Mesozoic data and the
Neogene data is an rotational gap of ~35°.
Earlier studies confirm the structural coherence of Sardinia from the Late
This study attempts to contribute to better time constraints for tectonic motions
of the CSM and determine whether the CSM was part of a bigger plate. A total of
~500 oriented core samples from 1 Triassic site, 2 Jurassic sites and 2
Cretaceous sites have been collected from the Nurra region. Samples taken from
the Jurassic of Nurra proved to be too weakly magnetized and did not yield any
stable directions. The Cretaceous results of one site did not yield high quality
data due to weak magnetization and consequently insufficient sampling.
The Triassic site yielded a characteristic remanent magnetisation (ChRM) of D=
297°, I= 38°, which is in good agreement with earlier published Triassic data.
Reliable Cretaceous data from Coniacian-Santonian rocks yielded a ChRM of D=
277°, I= 49°.
No significant rotation of Sardinia with respect to Europe is observed between
the Anisian (245.0 Ma) and the Santonian (83.5 Ma). The Nurra region and the
Iberian sub-continent do not share an apparent polar wander path. This implies
that Sardinia was in the Cretaceous not a part of Iberia, contrary to earlier
In the Coniacian-Santonian no rotation with respect to Europe is observed,
therefore first stage of rotation must have occurred later, between 85.8 Ma and