Paleomagnetic and geochronologic constraints on the geodynamic evolution of the Central Dinarides

Arjan de Leeuw; Oleg Mandic; Wout Krijgsman; Klaudia Kuiper; Hazim Hrvatović

doi:10.1016/j.tecto.2012.01.004

Paleomagnetic and geochronologic constraints on the geodynamic evolution of the Central Dinarides

Tectonophysics. 2012 Mar 20;530-531(2):286-298. doi: 10.1016/j.tecto.2012.01.004.

Authors

Arjan de Leeuw¹, Oleg Mandic², Wout Krijgsman¹, Klaudia Kuiper³, Hazim Hrvatović⁴

Affiliations

¹ Paleomagnetic Laboratory 'Fort Hoofddijk', Utrecht University, Budapestlaan 4, 3584 CD, Utrecht, the Netherlands.
² Department of Geology & Palaeontology, The Natural History Museum Vienna, Burgring 7, 1010 Wien, Austria.
³ Isotope Geochemistry, Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, the Netherlands.
⁴ Federal Institute for Geology, Sarajevo, Ustanička 11, 71210 Ilidža, Bosnia and Herzegovina.

Abstract

The geodynamic evolution of the Dinaride Mountains of southeastern Europe is relatively poorly understood, especially in comparison with the neighboring Alps and Carpathians. Here, we construct a new chronostratigraphy for the post-orogenic intra-montane basins of the Central Dinarides based on paleomagnetic and ⁴⁰Ar/³⁹Ar age data. A first phase of basin formation occurred in the late Oligocene. A second phase of basin formation took place between 18 and 13 Ma, concurrent with profound extension in the neighboring Pannonian Basin. Our paleomagnetic results further indicate that the Dinarides have not experienced any significant tectonic rotation since the late Oligocene. This implies that the Dinarides were decoupled from the adjacent Adria and the Tisza-Dacia Mega-Units that both underwent major rotation during the Miocene. The Dinaride orogen must consequently have accommodated significant shortening. This is corroborated by our AMS data that indicate post-Middle Miocene shortening in the frontal zone, wrenching in the central part of the orogen, and compression in the hinterland. A review of paleomagnetic data from the Adria plate, which plays a major role in the evolution of the Dinarides as well as the Alps, constrains rotation since the Early Cretaceous to 48 ± 10° counterclockwise and indicates 20° of this rotation took place since the Miocene. It also shows that Adria behaved as an independent plate from the Late Jurassic to the Eocene. From the Eocene onwards, coupling between Adria and Africa was stronger than between Adria and Europe. Adria continued to behave as an independent plate. The amount of rotation within the Adria-Dinarides collision zone increases with age and proximity of the sampled sediments to undeformed Adria. These results significantly improve our insight in the post-orogenic evolution of the Dinarides and resolve an apparent controversy between structural geological and paleomagnetic rotation estimates for the Dinarides as well as Adria.

Keywords: Adria; Chronostratigraphic review; Dinaride Lake System; Dinarides; Intra-montane basins; Paleomagnetic review.