Kras Frmilske doline v Krajinskem parku Boč-Donačka gora

Abstract

V Krajinskem parku Boc-Donacka gora, na vzhodnem robu slovenskega krasa, imamo solski primer pokrajine v kateri se je zakrasevanje povrsja »pravkar« pricelo. Ohranjene so oblike iz katerih lahko spoznamo postopni prehod iz recnega v kraski relief. Frmilska dolina je bila prvotno porecje v nekarbonatnih kamninah, ki pa je zaradi erozije »nasedlo« na karbonatno podlago in se prestavilo v podzemlje. Iz nekdaj enotnega porecja je nastalo 14 aktivnih slepih dolin in 14 zakraselih recnih dolin brez povrsinskega vodnega toka. Razclenjen povrsinski odtok se nadaljuje v sklenjen podzemni odtok vse do kraskih izvirov pri Studeniskem samostanu v dolini Dravinje. Na obmocju Frmilske doline lahko opazujemo se vec recnih in kraskih pojavov: jame, izvire, presihajoco mlako, udorno steno, sufozijske vrtace in požiralnike v nekarbonatnih kamninah, recne terase in suhe ali fosilne meandre v zakraseli dolini, obvisele doline in spodmole. In the Landscape Park Boc-Donacka Gora (eastern Slovenia), on the eastern edge of the Slovenian karst, we have a textbook example of a territory in which the karstic process has "just" started. There are preserved features, which allow us to understand the transformation from a fluvial landscape to a karstic one. Frmile Valley was originally a river valley in non-carbonate rocks, but due to erosion it became stranded on carbonate rocks. Its waters were mostly transferred to the underground drainage. Fragmentation of the former river valley formed 14 active blind valleys and 14 inactive river valleys that already lost all surface water to the underground drainage. The disconnected surface runoff recharges the same karst aquifer which springs are located at the Studenice Monastery in the Dravinja Valley. In the area of Frmile Valley several fluvial and karstic features can be observed, i.e. caves, springs, a periodic pond, a hill slope collapsed into an underground cave, numerous suffosion dolines and ponors in the non-carbonate rocks, river terraces, dry or fossil meanders in karst valley, hanging valleys, a rock shelter.