First Pre-Miocene Paleomagnetic Data From the Calabrian Block Document a 160° Post-Late Jurassic CCW Rotation as a Consequence of Left-Lateral Shear Along Alpine Tethys

The Calabrian block, along with Alboran, Kabylies, and Peloritani form isolated and enigmatic igneous/metamorphic terranes (AlKaPeCa) stacked over the Meso-Cenozoic sedimentary successions of the Apennines and Maghrebides. They are commonly interpreted as fragments of the Hercynian chain rifted apart from Europe during Jurassic Alpine Tethys spreading, drifted southward during Neogene roll-back of (Neo) Tethyan slab fragments for hundreds of kilometers on top of nappe piles. We report on the paleomagnetism of upper Triassic-lower Miocene sedimentary rocks from the Longobucco succession that is transgressive over the crystalline Sila Massif (NE Calabria). Well-defined magnetization directions carried by hematite were isolated in 10 sites (122 samples) in Jurassic rocks. Nine Toarcian and one Tithonian Ammonitico Rosso sites yielded a dual polarity A magnetization component whit a direction over 40 degrees from the geocentric axial dipole (GAD) field direction, that supports a positive fold test. Five sites yielded a B normal polarity component NE (<40 degrees) of the GAD direction characterized by a negative fold test. We interpret the B component as a Miocene magnetic overprint later clockwise rotated by similar to 20 degrees during the well-known Pleistocene (1-2 Ma) rotation of Calabria. When corrected for such rotation, the A component defines a similar to 160 degrees counterclockwise (CCW) rotation of the Calabrian block with respect to Europe. Of these, similar to 90 degrees likely occurred along with Corsica-Sardinia block during its Eocene-Miocene rotation from the Provencal margin. Thus, the Calabrian block underwent an additional Cretaceous-Eocene 70 degrees CCW rotation that we relate to Early-mid Cretaceous >500 km left-lateral transcurrent motion between Africa and Europe.

Automated summary

This study investigates the paleomagnetism of the Calabrian block and reveals evidence of a approximately 160-degree counterclockwise rotation of the block with respect to Europe. Additionally, a approximately 20-degree clockwise rotation during the Pleistocene period is also identified. The study suggests a potential approximately 70-degree counterclockwise rotation of the Calabrian block during the Cretaceous-Eocene period.