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Območje strunjanskega klifa gradi eocenski fliš. Faciesna združba je dokaj monotona, gre za menjavanje laporovcev in distalnih siliciklastičnih turbiditov z vmesnimi redkimi, vendar izstopajočimi plastmi kalciturbiditov. Med rtom Ronek in Sv. Križem smo posneli 216 metrov sedimentološkega profila. Iz celotnega zaporedja zaradi svetlejše barve izstopa 8 debelejših plasti karbonatnih turbiditov, ki sem jih detajlno raziskala v pričujoči diplomski nalogi. Najbolj reprezentativna je 145 centimetrov debela plast, kjer je razvidna popolna Boumova sekvenca, kjer vrhnjih 60 centimetrov predstavlja vrhnji (Te) del sekvence. Najdebelejša 5,7 metrov debela kalciturbiditna plast je pri Sv. Križu. Posebnost te plasti so veliki lapornati plastiklasti, ki so na površini večinoma izprani, zato ima kamnina votlikav videz. Ta plast se končuje s skoraj 3 metre debelo kapo apnenega laporja. Ostale kalciturbiditne plasti so tanjše in jih gradijo vrhnji deli Boumove sekvence. Debelozrnati kalciturbiditi so tipa rudstone do packstone in jih sestavljajo bentoške foraminifere, rdeče alge in ehinodermske ploščice, redkeje najdemo bioklaste školjk in briozojev. Pojavljajo se tudi apnenčevi klasti, ki vsebujejo biogeni drobir, ostrakode, planktonske foraminifere ter ponekod tudi rdeče alge. Pogosto nakazujejo plastične deformacije, zato so najverjetneje erodirani sedimenti zunanje platforme (rampe) ali pobočja. V drobnozrnatih kalkarenitih opazimo planktonske foraminifere in zrna kremena. Podolgovata zrna so orientirana vzporedno s plastnatostjo, vezivo pa je mikrit z veliko biogenega drobirja. Izvorno območje kalciturbiditov je bila Dinarska (Jadranska) karbonatna platforma, fliši na strunjanskem klifu ne vsebujejo erodiranih klastov starejših platformskih apnencev, kar nakazuje nerazbrazdan prehod med južneje ležečo Dinarsko karbonatno platformo in flišnim bazenom. The area of Strunjan cliff is built by Eocene flysch. The facies association is rather monotonous, it's about changing marls and distal siliciclastic turbidites, with intermediate rare, but outstanding calciturbite layers. Between cape Ronek and Sveti Križ we logged 216 meters long sedimentological section. From the whole sequence because of lighter color stands out 8 thicker layers of carbonate turbidites, which I researched detaily for my diploma thesis. The most representative is 145 cm thick layer, where complete Bouma sequence is visible, where the upper 60 cm represents upper (Te) part of sequence. The thickest 5,7 meters calciturbidite layer is at Sveti Križ. The special feature of this layes is large marly plasticlasts, which are mostly washed out on the surface, so the rock has a hollow appearance. This layer ends with a nearly 3 meters thick limestone marl cap. Other calciturbidite layers are thinner and formed by upper parts of Bouma sequence. Coarse-grained calciturbidites are rudstone to packstone type and are composed of benthic foraminifera, red algae and echinoderm fragments, rarely found are bivalve shells and bryozoans. Limestone clasts, containing biogenic debris, ostracods, planctonic foraminifera and some red algae also appear. They often indicate plastic deformations, so they are most likely eroded outer platform (ramp) or slope sediments. In fine-grained calcarenites we observe plankton foraminifera and quartz grains. Elongated grains are orientatied parallel to the bedding, matrix is micrite with a lot of biogenic debris. Source area of calciturbidites was Dinaric (Adriatic) Carbonate Platform, flysch on Strunjan cliff does not contain eroded clasts of older platform limestones, which suggests mostly unfurrowed transition between the south lying Dinaric Carbonate Platform and the flysch basin. |
