Palaeomagnetic results from the southeastern segment of the External Dinarides: call for a fresh view on the role of the Shkodër–Peć fault system
摘要
The Dinaric fold-and-thrust belt forms the link between the Alpine and Hellenic orogenic systems, where the transition between differently rotating domains is a key problem in Mediterranean tectonics. The Shkodër–Peć fault system has been regarded as a major structure within this transition and as a possible boundary between counter-clockwise-rotated northern and clockwise-rotated southern segments. This study tests this interpretation by investigating the palaeomagnetic evolution of the southeastern External Dinarides, focussing on the rotational history of the High Karst Unit, Dalmatian and Budva Zones relative to this major transverse structure. Palaeomagnetic investigation was conducted at 62 geographically distributed localities over these 3 zones. The main target was the Budva Zone, for which we document a general 50° clockwise vertical-axis rotation of post-Cretaceous age. An important feature of this zone is the fan-like distribution of clockwise-rotated declinations, which correlates with the general trend of the thrust front and is characteristic of a salient-recess-type thin-skinned thrust. Whilst the northwestern Dalmatian Zone shows no post-Cretaceous rotation, Jurassic localities of the southeastern High Karst Unit show clockwise rotation of similar magnitude to that of the Mesozoic localities of the Budva Zone. These clockwise rotations match those documented in the northwestern parts of the Hellenides. They indicate that the Shkodër–Peć fault system is not the primary boundary between differently rotating domains; instead, the main change occurs near the northwestern terminus of the Budva Zone.
Graphical abstract