Are “Collapse Dolines” Formed Only by Collapse?

Abstract

Razprava teče o udornicah, enem na videz najbolje definiranih površinskih kraških pojavov. Kljub temu je v literaturi zaslediti zelo različne poglede, nekateri vidiki njihove geomorfogeneze pa so bili doslej prezrti. Predvsem gre za za nadalnji razvoj globeli v kraškem površju, potem ko so prepadne stene udornice že uničene, pobočja oblikuje samo še žepasto preperevanje, denudacija pa se je zajedla že globoko pod dno nekdanjega jamskega rova. Take globeli imenuje avtor fantomske udornice. V nadalnjem obravnava pet v Sloveniji najbolj običajnih tipov udornic in jih klasificira s pomočjo terminologije splošne teorije sistemov. Zaključuje, da sam udor stropa ostaja bistven del celotnega procesa, je pa volumsko lahko zelo podrejen.

The paper concerns collapse dolines, which appear to be one of the best-defined surface karst phenomena. Despite this appearance, one may find quite different views in the literature, and some the aspects of their morphogenesis have been overlooked completely. Among these aspects the most obvious is the question of the ongoing development of the closed depression. After the perpendicular walls have disappeared, the slopes are reshaped only by pocket weathering, and denudation penetrates deep below the former level of the preexisting cave floor. Dolines at this stage of development have been termed phantom collapse dolines. Five of the most common collapse doline types found in Slovenia are considered in terms of general systems theory, leading to a conclusion that cave roof collapse remains the crucial event in a collapse doline’s development. However, the collapse event itself may be relatively subdued in terms of the volume of free fallen mass involved.