Toward understanding the post‐collisional evolution of an orogen influenced by convergence at adjacent plate margins: Late Cretaceous–Tertiary thermotectonic history of the Apuseni Mountains

Abstract

[1] The relationship between syn-to post-collisional orogenic shortening and stresses transmitted from other neighboring plate boundaries is important for understanding the kinematics of mountain belts, but has received little attention so far. The Apuseni Mountains are an example of an orogen in the interference zone between two other subduction systems located in the external Carpathians and Dinarides. This interference is demonstrated by the results of a combined thermochronological and structural field study that quantifies the post-collisional latest Cretaceous-Tertiary evolution. The exhumation history derived from apatite fission track and (U-Th)/He thermochronology indicates that the present-day topography of the Apuseni Mountains originates mainly from latest Cretaceous times, modified by two tectonic pulses during the Paleogene. The latter are suggested by cooling ages clustering around ∼45 Ma and ∼30 Ma and the associated shortening recorded along deep-seated fault systems. Paleogene exhumation pulses are similar in magnitude (∼3.5 km) and are coeval with the final collisional phases recorded in the Dinarides and with part of the Carpathian rotation around the Moesian promontory. These newly quantified Paleogene exhumation and shortening pulses contradict the general view of tectonic quiescence, subsidence and overall sedimentation for this time interval. The Miocene collapse of the Pannonian Basin did not induce significant regional exhumation along the western Apuseni flank, nor did the subsequent Carpathian collision. This is surprising in the overall context of Pannonian Basin formation and its subsequent inversion, in which the Apuseni Mountains were previously interpreted as being significantly uplifted in both deformation stages.Citation: Merten, S., L. Matenco, J. P. T. Foeken, and P. A. M. Andriessen (2011), Toward understanding the post-collisional evolution of an orogen influenced by convergence at adjacent plate margins: Late Cretaceous-Tertiary thermotectonic history of the Apuseni Mountains, Tectonics, 30, TC6008,

Heavy minerals and exotic pebbles from the Eocene flysch deposits of the Magura Nappe (Outer Western Carpathians, eastern Slovakia): their composition and implications on the provenance

“…In the pre-Alpine (Variscan) basement of the Tisza Mega-Unit the prevailing rock association consists of gneiss, micaschist, amphibolites, and granitoids (Szederkényi et al, 2012;Haas and Buday, 2014). Based on the palaeogeographic position of the Tisza Mega-Unit during the Eocene (Csontos, 1995;Csontos and Vörös, 2004;Handy et al, 2014;Kováč et al, 2016), palaeoflow analysis indicating the SE source (Koráb et al, 1962;Kováčik et al, 2011, our data), and the data dealing with its exhumation (e.g., Merten et al, 2011; until the Middle Eocene according to Kounov and Schmid, 2013), this unit could be a possible source area. Chemical analyses of garnets studied show similar composition to those from the Tisza Mega-Unit crystalline basement (cf.…”

“…The geological composition of the Silesian Ridge varied from north to south (Soták, 1992;Budzyń et al, 2008Budzyń et al, , 2011 and did not relate to the Bohemian Massif (Soták, 1990). Koráb et al, 1962;Stránik, 1965;Contescu et al, 1966;Nemčok et al, 1968;Marschalko, 1975;Marschalko et al, 1976;Soták, 1990;Mišík et al, 1991aMišík et al, , 1991bOszczypko andOszczypko-Clowes, 2006, 2009;Márton et al, 2007Márton et al, , 2013Schmid et al, 2008;Hnylko, 2011a;Merten, 2011;Merten et al, 2011;Kováčik et al, 2011Kováčik et al, , 2012Plašienka, 2012;Handy et al, 2014;Hnylko and Generalova, 2014;Plašienka and Soták, 2015;Hnylko O et al, 2015;Hnylko OM et al, 2015;Hnylko and Hnylko, 2016;Bónová et al, 2016Bónová et al, , 2017Kováč et al, 2016). MnZ -Monastyrets Zone; DB -Dukla basin, SR -Silesian Ridge, SSR -Sub-Silesian Ridge, KR -Kumane Ridge, SMR -South Magura Ridge (Cordillera); CWC -Central Western Carpathians, MHB -Myjava-Hričov Basin, EA -Eastern Alps; KhN -Kahlenberg Nappe; PKB -Pieniny Klippen Belt; BKU -Biele Karpaty Unit; INZ -Inacovce Zone; KRZ -Kricevo Zone; SZ -Szolnok Zone; T -Tisza Mega-Unit; MZ -Mecsek Zone, V-BZ -Villány-Bihor Zone, B-CZ -Békés-Codru Zone; D -Dacia Mega-Unit; TB -Transylvanian Basin (land and epicontinental area), MB -Maramures Basin (trough), VZ -Vezhany Zone; EV -Eastern Vardar ophiolitic unit; EC -Eastern Carpathians; MR -Marmarosh (Rakhov) Zone (elevation), ChN -Chornohora Nappe; SvN -Svydovets Nappe, SvB -Svydovets Basin (dipping part); KrN -Krasnoshora Nappe, Fore-Marmarosh Suture (Ceahlau): BrN -Burkut Nappe;...…”

Tectonic Models for the Evolution of Sedimentary Basins

“…The coupling between the mechanical extension of the Pannonian Basin and its thermal effects recorded in the Transylvanian Basin should have taken place in such a way that the intervening Apuseni Mountains did not underwent any significant Miocene vertical movements. The related exhumation and large-scale domal structure is mainly the effect of Cretaceous-Paleogene deformations (Merten et al, 2011). In contrast to earlier periods of extension, massive thermal-sag sedimentation is observed in direct relationship with and postdating the Pannonian-Lower Pontian detachments and/or normal faults (such as the Makó depression, Figure 28).…”

Heavy minerals from sedimentary rocks of the Malcov Formation and their palaeogeographic implications for evolution of the Magura Basin (Western Carpathians, Slovakia) during the Late Eocene – Late Oligocene

“…6.4D) and Apuseni Mts. (Tisza Mega-Unit) were exhumed Merten et al, 2011). How ever, it should be noted that the rocks from higher lev els of the meta mor phic com plexes were ex posed, and ow ing to the in creased con tent of car bon ate clasts along with the cover se quences or nappes of the Fore-Marmarosh Su ture -Kaminnyi Potik, Rakhiv and Burkut (Porkulets), rel a tively rich in car bon ates.…”