Successions of the Slovenian Basin structurally belong to the easternmost Southern Alps. During the Late Triassic, they were part of the Adriatic continental margin. Norian-Rhaetian successions of the Slovenian Basin are characterized mainly by dolomite of the Baba Dolomite Formation. However, in the northern part of the basin, Late Triassic limestone is preserved above Baba Dolomite Formation and is formalized as the Slatnik Formation. It is composed of hemipelagic limestone alternating with resedimented limestones. The succession documents an upward progradation of the slope environment composed of three high-frequency cycles. Most prominent progradation is referred to the second, i.e., Early Rhaetian cycle. The Slatnik Formation ends with thin-bedded hemipelagic limestone that records the end-Triassic productivity crisis, or rapid sea-level fall. The overlying resedimented limestones of the Early Jurassic Krikov Formation, document the recovery of production and shedding from the adjacent carbonate platform.

No abstract

No abstract

Izvleček UDK 551.435.84(497.471) Petra Žvab Rožič, Jože Čar & Boštjan Rožič: Geološka Struktura na območju Divače in njen vpliv na spelogenezo ter hidrogeologijo Kačne jame Jame se razvijajo vzdolž nezveznosti, sedimentarnega ali tektonskega izvora v zaporedju topnih kamnin. Na Klasičnem Krasu slednje predstavljata apnenec in dolomit. Predhodne raziskave kraških terenov jugozahodne Slovenije so pokazale jasno povezavo med smerjo jamskih kanalov in lokalnih strukturih elementov, kar se je pokazalo tudi na prikazanem območju kartiranja. Kačna jama je najdaljša jama Klasičnega Krasa in predstavlja pomemben del podzemnega toka reke Reke. S strukturnim kartiranjem površine nad jamo, ki je prilagojeno kraškim ozemljem, smo ugotovili potek treh SZ−JV prelomov in ene vmesne razpoklinske cone v enaki smeri. Te strukture so vzporedne regionalnemu Divaškemu prelomu, ki smo ga zaznali na skrajnem SV delu raziskanega območja. Med njimi potekajo prečno usmerjene razpoklinske cone, ki so deloma povite do smeri S−J. Opisano strukturo razlagamo s kompleksnim divergentno-konvergentnim desno-zmičnim prelomnim klinom. Posebej obravnavamo Risniški prelom, ob katerem sta razviti udornici Risnik in Bukovnik, ter nekaj večjih podorov v jami. V odtočni sifon na koncu Ozkega rova nizke vode odtekajo skozi Risniški prelom v smeri regionalnega gradienta. Medtem za visoke vode isti prelom predstavlja hidrogeološko zaporo, saj prej omenjeni odtočni sifon ne zmore več prevajati zadostnih količin podzemne vode in ta odteka vzdolž preloma po dobro razvitem sistemu kanalov v Nw smeri. Menimo, da ima Risniški prelom vlogo zapornega preloma.

The Middle and Upper Jurassic succession of the Slovenian Basin is characterized by pelagic sedimentation of siliceous limestones and radiolarian cherts. In the southern and central part of the basin two packages of resedimented limestones are interbedded within pelagic sediments. The Lower resedimented limestones are lower-middle Bajocian to lower Callovian in age. In the southern part of the basin they form laterally discontinuous sequences composed of limestone breccias, calcarenites and micritic limestone and in the central part of the basin calcarenite intercalations within pelagic beds. They were transported by turbidity currents from highly productive ooidal shoals of the Dinaric Carbonate Platform. The Lower resedimented carbonates correlate with the lower three members of the Travnik Formation in the Bovec Trough and similarly developed but much thicker Vajont Formation in the Belluno Basin. The difference in thickness is interpreted as a consequence of shallow-water and longshore currents on the Dinaric Carbonate Platform that transported platform material towards southwest in the direction of the Belluno Basin. The Upper resedimented limestones are upper Kimmeridgian to lower Tithonian and occur within radiolarian cherts in the upper part of the succession as calcarenite beds that originated by turbidity currents. Onset of resedimentation coincides with the emersion-related demise of barrier reef and following deposition of micritic and rare oolitic limestones on the Dinaric Carbonate Platform. Approximatelly coeval resedimented limestones occur in the fourth member of the Travnik Formation in the Bovec Trough, but are not reported from the Ammonitico Rosso Superiore Formation in the Belluno Basin. Kratka vsebinaSrednje in zgornje jursko zaporedje Slovenskega bazena ozna~uje prevladujo~a pelagi~na sedimentacija okremenjenih apnencev in radiolarijskih ro'encev. V ju'nem in srednjem delu bazena se med pelagi~nimi plastmi pojavljata dva nivoja presedimentiranih apnencev. Spodnji presedimentirani apnenci so odlo'eni v srednjem delu zaporedja in so spodnje ali srednjebajocijske do spodnjecalovijske starosti. V ju'nem delu bazena tvorijo lateralno prekinjene apnen~eve horizonte, ki jih sestavljajo apnen~eve bre~e, kalkareniti in mikritni apnenci. V srednjem delu bazena pa se pojavljajo kot posamezne kalkarenitne plasti okoli meje med okremenjenimi apnenci in radiolarijskimi ro'enci. Ti apnenci so nastali s presedimentacijo materiala s turbiditnimi tokovi iz visoko produktivnih ooidnih plitvin Dinarske karbonatne platforme. Spodnje presedimentirane apnence koreliramo s spodnjimi tremi ~leni Travni{ke formacije v Bov{kem jarku in podobno razvito, vendar mnogo debelej{o Vajont formacijo v Belluno bazenu. Razlike v debeline so predvidoma nastale kot posledica plitvovodnih tokov na Dinarski karbonatni platformi, ki so transportirali platformski material proti jugozahodu v smeri Belluno bazena. Zgornji presedimentirani apnenci so zgornjekimmeridgijske do spodnjetithonijske starosti in se pojavljajo med radiolarijs...