Exhumation history of the Tatry Mountains, Western Carpathians, constrained by low‐temperature thermochronology

Abstract

This study tests alternative models for the growth of the Tatry Mountains (Central Western Carpathians) by the application of low-temperature thermochronology. Zircon (U + Th)/He ages from the north of the range are mostly between 48 and 37 Ma and indicate cooling prior to the onset of fore-arc sedimentation in the region (42-39 Ma). In contrast, zircon (U + Th)/He ages in the south of the range are around 22 Ma. Apatite fission track ages across the sampled sites range from 20 to 15 Ma. Apatite (U + Th)/He ages range from 18 to 14 Ma with little variation with elevation or horizontal location. Based on thermal modeling and tectonic reconstructions, these Miocene ages are interpreted as cooling in the hanging wall of a northward dipping thrust ramp in the current location of the sub-Tatric fault with cooling rates of 20°C/Myr at~22-14 Ma. Modeled cooling histories require an abrupt deceleration in cooling after~14 Ma to <5°C/Myr. This is associated with termination of deformation in the Outer Carpathians and is synchronous with the transition of the Pannonian Basin from a syn-rift to a postrift stage and with termination of N-S compression in the northern part of the Central Western Carpathians. Overall, the timing of shortening and exhumation is synchronous with the formation of the Outer Carpathian orogen and so the Miocene exhumation of the Tatry records retrovergent thrusting at the northern margin of the Alcapa microplate.

Building and exhumation of the Western Carpathians: New constraints from sequentially restored, balanced cross sections integrated with low‐temperature thermochronometry

“…Cooling ages ranging between 20 and 15 Myr characterize the western Polish OC successions, whereas a more recent exhumation event (8–20 Myr) involves the PKB deposits. Cooling ages for the PKB are consistent with the published exhumation ages for the IC domain [ Burchart , ; Baumgart‐Kotarba and Král , ; Danišìk et al ., , , , , ; Śmigielski et al ., , ], thus suggesting a common cooling event for these two different tectonic domains, as shown in our structural model [see also Castelluccio et al ., ]. Forward modeling allowed us not only to validate the geological cross sections and contextualize the thermochronometric data sets but also to calculate the shortening rate for each step of the reconstructed tectonic evolution.…”

“…[, and references therein]). For the IC s.s., apatite fission track (AFT) and apatite (U‐Th)/He (AHe) data suggest that the last cooling event is not older than 20 Ma for both the crystalline massifs and the Paleogene deposits of the CCPB [ Anczkiewicz , ; Anczkiewicz et al ., , ; Danišìk et al ., , , , and references therein; Śmigielski et al ., , ]. This feature has been interpreted by Danišìk et al .…”

“…Several low‐T themochronometric data sets are available for this study area [ Anczkiewicz , ; Anczkiewicz et al ., , ; Andreucci et al ., ; Burchart , ; Danišìk et al ., ; Král ', ; Králiková et al ., , ; Struzik et al ., ; Śmigielski et al ., , and data herein]. The oldest ages have been detected by the 40 Ar/ 39 Ar system [ Hók et al ., ; Putiš et al ., ] in the Lúčanská Fatra Mountains (IC) (see Figure for location).…”

“…In the Tatra Mountains, another possible explanation for the Middle/early late Miocene exhumation could be the activation of the Sub‐Tatra fault, whose kinematics is still poorly known due to the occurrence of thick Quaternary cover. This fault has been either interpreted as south dipping normal fault [ Hrušecký et al ., ; Jurewicz , ] or as north dipping reverse fault [ Sperner , ; Śmigielski et al ., ]. Králiková et al .…”

New data on the age of the sedimentary infill of the Orava-Nowy Targ Basin – a case study of the Bystry Stream succession (Middle/Upper Miocene, Western Carpathians)

“…Sev eral in de pend ent mod ern surveys based al to gether on >50 sam ples pointed to a time in ter val from ~22 to ~10 Ma as the main ep i sode of Neo gene ex hu mation and the re lated fault ac tiv ity in the Tatra Mas sif (Králiková et al, 2014;Anczkiewicz et al, 2015;Śmigielski et al, 2016). At the time of sed i men ta tion of in ves ti gated tuffite (~12 Ma), the faults that bound the Tatra Mas sif from the west (Choč --Prosečné-Krowiarki Fault) and from the east (Ružbachy Fault) acted most prob a bly as strike-slip sinistral faults and sub-Tatra Fault as a re verse struc ture (Sperner et al, 2002;Králiková et al, 2014;Śmigielski et al, 2016). The ~12 Ma age of the tuffite in the Bystry Stream area fits well into these re sults and the follow ing tec tonic in ter pre ta tion.…”