ALBERT

Description:    Scarce basin remnants of Cretaceous synorogenic sediments exposed in the Medvednica, Ivanščica, Žumberak Mts. and Samobor Hills of northern Croatia record the early orogenic history of the NW Dinarides. The provenance of sandstones from five clastic formations (Oštrc, Bistra, Kravljak, Vivodina and Glog) which cover a time span from Early to late Late Cretaceous was studied by combining petrography, whole-rock geochemistry, heavy mineral chemistry and detrital zircon fission track dating. These sediments record at least two major regional thermotectonic events which correlate well with those affecting both the Alps and the Tisza-Dacia unit to the north and east, and the central Dinaride region to the south. Short zircon fission track lag times in Barremian to Albian sediments indicate that continental fragments of the distal Adria plate margin underwent relatively fast, synsedimentary exhumation in the Early Cretaceous. Moreover, a clear dominance of Campanian zircon cooling ages (80–73 Ma) in Maastrichtian sandstones indicates detritus deriving from the erosion of newly and rapidly exhumed basement units which had undergone Late Cretaceous metamorphism in the Eastern Alps and/or the Tisza-Dacia region. Probably, the rapid Maastrichtian erosion generating metamorphic detritus occurred to a great extent on neighbouring Austroalpine basement units, and/or on the upper plate Tisza-Dacia unit during the subduction stage or the initial stages of the continent–continent collision with Adria. Development of the accretionary wedge probably resulted in a renewed availability of ophiolites for erosion within small and/or dynamically changing catchments, which can be deduced from the notable differences in reconstructed source lithologies for the coeval Glog and Vivodina formations. Combined evidence from sedimentary provenance indicators precludes the Dinaride (Adriatic) basement as a significant source for the Maastrichtian sediments. Content Type Journal Article Pages 1-23 DOI 10.1007/s00015-012-0107-3 Authors Borna Lužar-Oberiter, Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia Tamás Mikes, Abteilung Sedimentologie/Umweltgeologie, Geowissenschaftliches Zentrum der Universität Göttingen, Goldschmidtstrasse 3, 37077 Göttingen, Germany István Dunkl, Abteilung Sedimentologie/Umweltgeologie, Geowissenschaftliches Zentrum der Universität Göttingen, Goldschmidtstrasse 3, 37077 Göttingen, Germany Ljubomir Babić, Department of Geology, Faculty of Science, University of Zagreb, Horvatovac 102a, 10000 Zagreb, Croatia Hilmar von Eynatten, Abteilung Sedimentologie/Umweltgeologie, Geowissenschaftliches Zentrum der Universität Göttingen, Goldschmidtstrasse 3, 37077 Göttingen, Germany Journal Swiss Journal of Geosciences Online ISSN 1661-8734 Print ISSN 1661-8726