Horst Structure and Planation Surfaces—Little Carpathians Mts.

Abstract

The Little Carpathians form the most distant, southwestern promontory of the Western Carpathians, wedged between the Záhorská and Podunajská lowlands. They represent mountains individualized and internally differentiated by multidirectional geomorphological lines arranged in a geomorphological grid typical for horst morphostructures. The Little Carpathians are divided into six morphostructural units, which are further differentiated into lower order morphostructural units. In addition to the morphostructural regionalization, the chapter presents the basic scheme of geomorphological development of the Little Carpathians during the neotectonic period. The initial relief of the study area was likely a low ridge individualized in the Badenian period, within roughly similar boundaries as the contemporary mountains. In the changing morphostructural and morphoclimatic conditions, gradual transformation of the relief into a rising horst occurred, which, however, did not behave as an internally homogeneous morphostructure. Its complexity was dictated by different structural-lithological properties of the geological substratum, especially by the diverse developments of its morphostructural units. Therefore, the nature and intensity of transformation processes varied from place to place. In principle, the replacement of old forms by the new ones has progressed from the edge of the mountain range to its interior. So, planation surfaces and subsequent valleys originating in the Neogene can be found in its central part, while the slopes and valleys in the foothills are younger, of Quaternary age. Climatic oscillations of the Quaternary period had a great influence on the transformation of the relief. In the contact area between the mountains and the lowlands, the youngest development of relief is characterized by very intensive anthropogenic impact and its transformation.