Multi-level Domica–Baradla cave system (Slovakia, Hungary): Middle Pliocene–Pleistocene evolution and implications for the denudation chronology of the Western Carpathians
Résumé
The trans-boundary Slovak-Hungarian Domica-Baradla cave system (Slovak and Aggtelek karsts), >26 km in length, consists of evolution levels that have been formed in relation to the incision phases of the Josva Valley. Existing opinions on the age of the well-known cave system have not been based on the dating of cave sediments deposited during older evolution phases. Previous U-series dating and the first paleomagnetic analyses of dripstones, flowstones and fine-grained allochthonous sediments identified only younger accumulative phases of the cave evolution in Late Pleistocene. Our cosmogenic nuclide dating (Be-10 and Al-26) of allochthonous fluvial gravels from the upper and lower levels of the Domica Cave (Slovakia) reveal much older evolution phases. Two burial ages at 3.47 +/- 0.78 Ma and 2.94 +/- 0.50 Ma show that the upper level of the cave system originated in, or before, the Middle Pliocene. Its younger accumulation phases (Early-Middle Pleistocene) are documented based on magnetostratigraphy and U-series dating of fine-grained sediments and flowstones. The Brunhes/Matuyama boundary (780 ka), Kamikatsura excursion (similar to 900 ka), Santa Rosa excursion (similar to 932 ka) and Jaramillo magnetozone (similar to 1.001-1.069 Ma) were identified from the newly studied profile in the Sucha chodba Passage (the ages of flowstones in upper part of this profile are similar to 130 ka, 173 ka and 199 ka). In some places, several small older (paleokarst?) solutional phreatic cavities are cut by this cave level. The lower evolution level, located 12-18 m below the upper level, originated in the Early Pleistocene (the burial age of allochthonous fluvial gravels is 1.92 +/- 0.25 Ma). Low pre-burial denudation rates (3.1-5.6 m/Ma) correspond with the slowdown or interruption of tectonic uplift of the area and the long-term stabilized erosion base level during the formation of these cave levels. Their origin was linked with the formation of large pediments, of which remnants are preserved on both sides of the Josva Valley (Hungary). The pediments probably correlate to the 'foothill' (Middle Pliocene) and 'river-side' (Late Pliocene-Early Pleistocene) levels in the denudation chronology of the Western Carpathians.