Late Cretaceous-Cenozoic thermal evolution of the northern part of the Central Western Carpathians (Slovakia): revealed by zircon and apatite fission track thermochronology

- Thermal evolution of source-sink system was studied by FT analysis.
- Six tectono-thermal phases were determined by FT dating and geological constraints.
- Cenozoic intramontane basin originated due to post-Cretaceous orogenic collapse.
- Northward migration of the mountains exhumation process was documented.
- Time-temperature evolution of study area was inferred from FT and geological data.

Tectono-thermal evolution of the northern part of Central Western Carpathians (Slovakia) was revealed by zircon and apatite fission track thermochronology of Neogene deposits, volcanic rocks, and crystalline basement. New fission track ages combined with previous geochronological data are correlated with main tectonic events and important palaeogeographic changes. (1) The palaeo-Alpine burial to more than 10 km depths, heating (> 320 °C) and low-grade metamorphism of the crystalline basement was caused by crustal thickening due to nappe stacking driven by the collisional processes (~ 90-75 Ma). (2) Extensional collapse and exhumation of basement complexes during the Late Cretaceous to Middle Eocene (~ 75-40 Ma). (3) The extension process resulted in a new sedimentary cycle of the Central Carpathian Palaeogene Basin (~ 40-25 Ma) in the northern part of the Central Western Carpathians. During the ensuing burial under the thick sedimentary cover, the crystalline basement of the northern zone resided at 'hotter' conditions (ca. > 120 °C and < 200 °C) which led to full annealing of apatite single-grain ages. In the meanwhile the southern zone of the crystalline basement was gradually exhumed to the depth of 5-3 km and occasionally appeared at the erosion surface. (4) Disintegration of the Central Carpathian Palaeogene Basin (~ 25-20 Ma) was closely connected with a partial exhumation of the Central Western Carpathians and intensive denudation. (5) The Middle to Late Miocene (~ 20-9 Ma) subduction of the Outer Carpathians substratum had crucial consequences for the tectonic evolution of the hinterland that was located in the upper crustal plate. The most external zone of the hinterland basement domain (Lúčanská and Krivánska Fatra Mts.) was exhumed to the 5-3 km depth and the intramontane basins were opened. (6) New fission track data and geomorphological criteria refer to the Pliocene-Quaternary mountain building processes in the external zones of the Central Western Carpathians.