Морфология на младия карст в района между долините на реките Бели Лом и Малки Лом

Т. Кръстев. Морфология на младия карст в района между долините на реките Бели Лом и Малки Лом

T. Krastev.Adolescent karst morphology in the region between the Beli Lom and Malki Lom river valleys

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ADOLESCENT KARST MORPHOLOGY IN THE REGION BETWEEN THE BELI LOM AND MALKI LOM RIVER VALLEYS

Todor Krastev

Two karst groups of different age developed in the region under investigation — old and adolescent. The last karst group with its various forms and surface morphological complex in particular is subjected to studies in the article.

The adolescent karst evolution has been in progress in Neogene-Quaternary period. As soon as the Beli Lom river bed, formed in Pleo-Pleistocene as a result of differentiated neotectonic positive movements, was drained, favourable conditions for karst development came into being. A surface run-off originated in some shallow lowerings of this ancient terrace. Their orientation was dependent on one or other fissure system, predominating in the region. In space and time the erosion activities of running water gradually abated while karst processes came to the fore. Most of the embryonic erosional forms widened and deepened. So karst corrosion converted the former fluvial forms into whirlpools and ponors. Those periods, which have been relatively motionless from a tectonic point of view and caused the karst level to stagnate, marked the main stages of horizontal karst development within the whole surface morphological complex, belonging to the adolescent karst group. Vertical karst development coincided with the Beli Lom river incision by stages.

The above mentioned karst is proved to be adolescent because when the loess drifting started, numerous distinctly outlined uvals and whirlpools have been already existing.

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