Gemorphogenetics of the Classical Karst - Kras

Abstract

V času med eocenom in pliocenom so bile s temena krednega apnenčevega antiklinorija v osrednjem in zahodnem delu planote Kras in s kozinsko-podgrajske antiklinale erodirane flišne plasti, zaradi česar se je ob splošnem zniževanju okoliške ravnine ob pogojih zajezenega krasa razširjal in zniževal ravnik na razkritih apnencih. Največji del planote Krasa predstavlja najstarejši del kraškega ravnika. Na Krasu so se v pliocenu in kvartarju pasovi ravnika hitreje zniževali v smeri proti SZ, vmesno zastajajoče ali dvigujoče se površje pa je s tem dobilo obliko vzpetin na severozahodnem robu planote. Zaradi hitrejšega grezanja vipavske sinklinale so vodni tokovi prenehali teči preko planote Krasa še preden je bil fliš, ki jim je preprečeval pot proti jugu, odstranjen zaradi grezanja severnega dela Tržaškega zaliva. Zaradi tega na Krasu ni slepih dolin ali polj. Pač pa je veliko vrtač, površje je kamnito, zaradi česar je iz Krasa nastal splošni pojem kras. Obe značilnosti sta tipični za submediteranske dinarske kraške ravnike, gosto naseljene in obdelane ter zaradi tega brez gozdov

Between Eocene and Pliocene, erosion of flysch strata on the top of Cretaceous limestone anticlinorium in the central and western part of the Kras plateau and the Kozina-Podgrad anticline uncovered and widened – and simultanously lowered - the karst plain in the conditions of dammed karst. The largest portion of Kras plateau is covered with karst plain, its oldest part. In Pliocene, the karst plain was fractured and subsided towards the NW regardless of older folded structure; during this process, several zones of elevations were formed through slower subsiding or uplifting. Due to faster lowering of the Vipava syncline, water streams stopped running over the Kras plateau before the flysch, damming the waters from the Kras plateau to the south was removed due to the subsiding in the northern Gulf of Trieste. Thus, no fossil blind valleys or poljes are found on the Kras plateau. However, there is considerable density of dolines and the surface is stony, giving the karst its original name. Both phenomena are typical of deforrested, densely populated and cultivated Submediterranean Dinaric karst plains.