Age and environmental conditions for the formation of the Pannonian mega-yardang system

The Pannonian mega-yardang system is the northernmost mega-yardang field in Europe, exerting a profound influence on the relief and surface hydrographic structure of Western Hungary. Despite its significance, the precise timing and climatic conditions under which this mega-yardang system formed remain elusive. The geological setting was studied, the former humidity and biome patterns were modelled, the climatically analogous regions of the past climates of the region were identified, and the Köppen Aridity Indices of the region were compared to the aridity values of other yardang fields from five continents in the last 3.3 mys. The geological structure of the yardangs suggests an origin post-dating the Tortonian period but preceding the mid-Pleistocene era. In the Zanclean and in the warmer periods of the Piacenzian, the studied region had humid subtropical climatic conditions that were not suitable for the formation of large-scale aeolian landforms. Similarly, in the Quaternary period, the climate varied between boreal and humid continental, which was not conducive to the formation of mega-yardang fields. Cold semi-arid climatic conditions only existed in the mid-Pliocene cold period and perhaps at the transition of the Pliocene to the Pleistocene. This paleoclimatic hypothesis is in accordance with the Pliocene fossil record of the region, which contains the remains of such arid habitat-dwelling fauna elements as camelids and struthionids. The comparison of the development of Köppen Aridity Indices among yardangs in other territories also suggests that the Pannonian mega-yardang system may have formed around the transition of the Neogene to the Quaternary epochs.

Graphical abstract