This paper attempts to explain the tectonic history and possible reasons for the change of trend of the northwestern part of the Internal Dinarides in a transitional area between the Southeastern Alps, central Dinarides and Tisia, north of Zagreb. Structural and palaeomagnetic data collected in pre-Neogene rocks at Medvednica Mountains, combined with palaeomagnetic data available from Neogene rocks in the surrounding area, point to the following conclusions:(1) The reason for dramatic deflection in structural trend of the Internal Dinarides in the area north of Zagreb is a 1308 clockwise rotation and eastward escape of a tectonic block comprising Medvednica Mountains and the surrounding inselbergs, bounded to the north by the easternmost tip of the Periadratic Lineament. In Medvednica Mountains, the main period of tectonic escape and associated clockwise rotation occurred in the Late Palaeogene, possibly in the Oligocene-earliest Miocene.(2) When rotated into the original position, the trend of observed pre-Neogene structures of Medvednica Mountains becomes parallel to the major structural trend of the central Dinarides. In view of their original orientation, these structures are interpreted in the following way:(a) The first D1 deformational event is attributed to the Aptian-Albian nappe stacking in the central-northern Dinarides that was accommodated by a top-to-the-north directed shearing and northward propagation of already obducted ophiolites of the Central Dinaridic ophiolite zone. This nappe stacking, which resulted in a weak regional metamorphism in tectonic units underlying the ophiolites, was orogen-parallel or at a very acute angle to known structural (and possibly palaeogeographic) trends. This implies a major left-lateral shear component along the former Adriatic margin and obducted Dinaridic ophiolite zone.(b) This was followed by Early Albian orogen-perpendicular shortening (D2) that was accommodated by folding and top-to-the-west thrusting. This deformation resulted in gradual cooling of the metamorphic stack and also in uplift and erosion of the higher structural units.(c) The D3 deformational event was driven by renewed E -W shortening that took place after the Paleocene, most probably during the Middle Eocene-Oligocene, i.e. synchronous with the main Dinaridic tectonic phase of the External Dinarides. This shortening was probably triggered by collision and thrusting of Tisia over the northern segment of the Internal Dinarides.(d) This was finally followed by D4 pervasive, right-lateral N-S shearing that is tentatively interpreted as being related to the right-lateral shearing of the Sava zone during the Eocene-Oligocene.(e) Following the main period of tectonic escape and induced clockwise rotation along the Periadriatic fault, possibly in the Oligocene-earliest Miocene, the Medvednica Mountains and the surrounding area were affected by repeated extensions and inversions since the Early Miocene to recent times. Palaeomagnetic data suggest that in the Early Miocene (but probably before the Karpa...

Paleomagnetic analyses were carried out on samples from 19 localities within two different mega-tectonic units in Northern Romania: Tisza-Dacia (11 localities) and ALCAPA (8 localities). The samples cover a range of different lithologies: (1) Late Cretaceous red-coloured marl to marly limestone, (2) EoOligocene flysch sediments, and (3) mid-Miocene (Langhian) tuffite (Dej tuff and related sediments). The Late Cretaceous and mid-Miocene specimens carry secondary paleomagnetic signals exhibiting a counter clockwise deflection of the paleo-declinations by some 30°, while the Eo-Oligocene localities indicate an overall clockwise deflected (between some 45°and >90°) paleodeclination with respect to present-day north. Clockwise rotation postdates the age of sedimentation (Lower Oligocene), as well as (at least partially) thrusting of the Pienides onto the Tisza-Dacia mega-tectonic unit, which occurred between 20.5 and 18.5 Ma. Clockwise rotation predates post-12 Ma counter clockwise rotations inferred for the mid-Miocene localities.Surprisingly, the clockwise rotations of the first rotational stage not only affected the (par-) autochthonous sedimentary cover of the Tisza-Dacia megatectonic unit, but also the allochthonous flysch nappes of the Pienides, i.e. the eastern tip of the ALCAPA mega-tectonic unit. Well-documented opposed rotation of the remainder of ALCAPA necessitates a detachment of this eastern tip of ALCAPA after 18. Die Rotation der Eo-Oligozänen Proben fand nach der Sedimentation der jüngsten Proben (unteres Oligozän), und zumindest teilweise nach dem Deckenschub der Pieniden (20.5-18.5 Ma) auf den Tisza-Dacia Block statt. Diese Rotation mit dem Uhrzeigersinn geht der durch die mittel-Miozänen Proben dokumentierten gegenläufigen Rotation (ab 12 Ma) voraus.Die Rotationen der früheren Phase wurden nicht nur in den Sedimenten aus der (par-) autochthonen Bedeckung von Tisza-Dacia, sondern auch in den überschobenen Pieniden nachgewiesen. Dieses Ergebnis ist auf den ersten Blick überraschend, da sie Teil von ALCAPA sind, der Rest von ALCAPA zu dieser Zeit aber in einem gegenläufigen Sinn, also gegen den Uhrzeigersinn, rotierte. Diese gegenläufigen Rotationen erfordern also eine tektonische Ablösung der östlichsten Spitze von ALCAPA vom Rest dieser grosstektonischen Einheit. Der wahrscheinlichste Ort für eine solche Ablösung befindet sich an den Rändern der Transkarpathischen Depression. Die zweite Rotationsphase, ca. 30°gegen den Uhrzeigersinn nach 12 Ma, ist auch aus dem OstSlovakischen Becken bekannt. Sowohl die Internen West-Karpathen westlich des Ost-Slovakischen Beckens, als auch das südliche Apuseni Gebirge, zeigen nach 12 Ma ein vom Arbeitsgebiet abweichendes Rotationsverhalten.

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