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Že v sklopu predhodnih raziskav smo v dolini pod Peski v Julijskih Alpah preučevali rdeče sedimentne zapolnitve zgornje triasnih megalodontidnih školjk. Na podlagi optične in katodoluminiscentne mikroskopije ter rentgenske fluorescenčne analize smo potrdili štiri generacije zapolnjevanja školjk. Ker je eno izmed temeljnih vprašanj predhodnih raziskav, vezano predvsem na izvor sedimenta v megalodontidah, ostalo delno neodgovorjeno, smo se odločili še natančneje raziskati tamkajšnjo okolico. Detajlno smo popisali in vzorčili kamninsko zaporedje nekaj metrov pod in nad »glavno« plastnico z zgoraj omenjenimi megalodontidami. Že med prvotnim vzorčenjem smo namreč opazili, da se v obdajajočih kamninah pojavljajo paleokraške votlinice, ki so zapolnjene s podobno obarvanim rdečkastim sedimentom, oziroma kamnino, kot v megalodontidah. Z namenom dodatnega preučevanja neptunskih dajkov in njihovega vpliva na zapolnitve v zadnji generaciji smo podrobneje raziskali še dodatnih pet dajkov v bližnji okolici. Na podlagi izbranih vzorcev smo izdelali detajlne mikrofacielne analize sedimentacijskega zaporedja in neptunskih dajkov. Preučevani profil dachsteinskega apnenca večinoma predstavljajo plasti intraklastičnih peloidnih apnencev tip packestone do wackestone z večjimi bioklasti (megalodontide, polži) in korozijskimi votlinicami. V nekaj vzorcih smo na večjih bioklastih opazili prevleke mikroproblematike Thaumatoporella. V zgornjem delu profila se pojavijo plasti s stromatolitnimi laminami in plasti emerzijskih breč s črnimi intraklasti (»black pebbles«). Slednji se ponekod pojavljajo tudi v rdečih paleokraških sedimentnih zapolnitvah. V korozijskih votlinicah smo opazili večgeneracijsko zapolnjevanje z menjavanjem kalcitnega cementa in rdečih sedimentnih zapolnitev. Preiskovane neptunske dajke smo pri opisih generalno razdelili na podlagi dimenzij in lokacije pojavljanja. Dva izmed njih, ki se nahajata neposredno na »glavni« plastnici z rdeče zapolnjenimi megalodontidami in vsebujeta planktonske foraminifere, kar kaže na srednjejursko oz. mlajšo starost. Naslednja dva preučevana dajka se nahajata tik nad »glavno« plastnico. Eden izmed njiju vsebuje klaste s kalpionelami, značilne za obdobje pozne jure do začetka krede. Zadnji dajk, katerega smo raziskovali, se nahaja nekaj deset metrov stran od »glavne« plastnice in je mnogo večjih dimenzij kot vsi prejšnji. Gre za več sto metrov dolg neptunski dajk z raznolikimi sedimentnimi zapolnitvami, ki kažejo na več ločenih faz zapolnjevanja. V nekaj vzorcih smo v tem dajku določili spodnjekredne planktonske foraminifere. Na podlagi mikroskopske analize se je izkazalo, da so rdečkaste paleokraške sedimentne zapolnitve v korozijskih votlinicah izredno podobne sedimentnim zapolnitvam prve in druge faze v megalodontidnih školjkah. Zapolnitve so torej del kompleksnejšega paleokraškega sistema, ki ga opazujemo v dachsteinskemu apnencu. Pomembnejše ugotovitve v povezavi z zadnjo fazo zapolnitev školjk smo dognali s pomočjo sedimentarne analize neptunskih dajkov, kjer se je pokazala mikrofacielna podobnost med zadnjo sedimentno zapolnitvijo v megalodontidah in nekaterimi neptunskimi dajki na »glavni« plastnici. Za zaključek in odprt konec raziskave pa smo v zgornjem delu profila v eni izmed korozijskih votlinic odkrili santonijsko – maastrichtijsko sedimentno zapolnitev z globotrunkanami. As part of the previous research, we have examined red fillings of the Upper Triassic megalodontid bivalves at a selected location in the Julian Alps, in the Pod Peski Valley. Based on optical and cathodoluminescent microscopy and X-ray fluorescence analysis (XRF), we confirmed four generations of shell infillings. Since one of the basic questions of previous research, mainly related to the origin of the last generation of the sediment infill in megalodontids remained unanswered, we decided to further examine this area. We described and in detail sampled the rock sequence a few meters below and above the »main« layer with the above-mentioned megalodontids. Already during the previous sampling campaign, we noticed that solution voids appear in the surrounding rocks. These voids are filled with reddish sediment infill, similar to that in the megalodontids. In order to further study neptunian dykes and their impact on fillings in the last generation, we investigated in more detail five additional dykes in the surrounding area. Based on selected samples, we performed a detailed microfacies analysis of sediment sequence and neptunian dykes. The studied section of Dachstein limestone mainly consists of intraclastic peloidal packestone to wackestone with larger bioclasts (megalodontides, gastropods) and solution voids. In a few samples, we observed a presence of Thaumatoporella. Stromatolites and emersion breccias with black intraclasts (»black pebbles«) appear in the upper part of the section. These intraclasts also appear in some places in red paleokarst solution voids. In thesolution voids, we observed a multi-generational filling with alternation of calcite cement and red sedimentary fillings. The investigated neptunian dykes were generally divided on the basis of dimensions and location of occurrence. Two of them, located directly on the »main« layer with red-filled megalodontids, contain planktonic foraminifera, which indicates the Middle Jurassic or younger age. The next two studied dykes are located just above the »main« layer, one of which contains clasts with calpionellis, characteristic of the Late Jurassic / Early Cretaceous . The last dyke we explored is located a few tens of meters away from the »main« bedding plane and is much larger than all the previous ones. It is a hundreds of meters long, with diverse sedimentary fillings indicating several separate generations of filling. In a few sample from this dyke we identified Early Cretaceous planktonic foraminifera. Based on microscopic analysis, the reddish paleokarst sedimentary fillings in the solution voids were found to be remarkably similar to the sedimentary fillings of the first and second phases in the megalodontid bivalves. The fillings are part of the more complex paleokarst system observed in the Dachstein limestone. More important findings, related to the last generation, were also found in the neptunian dykes, where optical microscopy also showed similarity between the last sediment filling in megalodontids and some neptunian dykes on the »main« bedding plane. For ending of our research, we discovered a Santonian - Maastrichtian sedimentary filling with globotruncanid foraminifers in the upper part of the succession in one of the solution voids.

Begunjščica je pogorje v Južnih Karavankah. Jurske plasti na Begunjščici izdanjajo na njenem južnem pobočju in so relativno dobro razgaljene. Begunjščica tako predstavlja pomembno območje za razumevanje jurske sedimentarne evolucije Julijskega praga. Jurske plasti loči vsaj en močnejši prelom, ki jih razdeli na severni in južni blok. V svoji magistrski nalogi sem preučila in opisala jurske plasti v južnem tektonskem bloku Begunjščice. Izdelala sem sedimentološki profil in iz detajlne mikrofacielne in biostratigrafske analize interpretirala sedimentarno evolucijo jurskega zaporedja. Obravnavano zaporedje sem razdelila na štiri glavne litostratigrafske enote. Profil se začne z mikritnimi apnenci z biogenim drobirjem in vmesnimi apnenčevimi brečami, ki so se odlagali na že poglobljenem območju v zgodnji juri. Prisotni so tudi manganovi gomolji in skorje, ki kažejo na izredno počasno sedimentacijo. Sledi izrazito nepravilna meja in nato kratko zaporedje glinavcev, laporovcev, rožencev in apnencev, močno obogatenih z manganom in manganovimi skorjami, katerih spodnji del je verjetno sočasen s spodnjetoarcijskim oceanskim anoksičnim dogodkom. Zaporedje se v toarciju nadaljuje s kondenziranimi apnenci tipa ammonitico rosso, med katerimi se prav tako pojavljajo apnenčeve breče, z manganiziranimi klasti in klasti starejših kamnin. Proti vrhu profila se zaporedje vedno bolj spreminja v močno sinsedimentno deformiran apnenec s kaotično strukturo, ki je nastal s sinsedimentnimi plazovi. Starost teh plasti je vprašljiva, lahko da so še toarcijske starosti, možno pa je, da so iz sredine srednje jure in je pod njimi stratigrafska vrzel. Profil se zaključi z menjavanjem pelagičnih in turbiditnih sedimentov, ki najverjetneje predstavljajo apnenčeve razvoje pred plastnatimi roženci, ki se na severnem bloku Begunjščice začnejo odlagati neposredno preko tanke plasti kaotične apnenčeve breče, profil južnega bloka pa jih več ne zajema. Analiza jurskih plasti južnega bloka Begunjščice je potrdila podobnosti z razvoji severnega bloka, kar dokazuje, da se jursko zaporedje na južnem pobočju večkrat ponovi zaradi manjših gub in preloma. Zaporedji se sicer razlikujeta predvsem v debelini plasti, kar kaže na verjetno bolj potopljen južni blok že v juri. Današnji prelom je najverjetneje samo reaktiviran mezozojski normalni prelom. Regionalna korelacija pokaže, da na ožjem območju nekdanje Julijske karbonatne platforme primerljivih razvojev s toarcijskimi apnenci tipa ammonitico rosso ni, so pa ti značilni za ostale paleogeografske enote Južnih Alp in tudi ostala območja jurskega pasivnega roba Jadranske mikroplošče. Mt. Begunjšcica is a mountain range in the Southern Karavanke Mountains. The Jurassic beds of Mt. Begunjšcica are relatively well exposed on its southern slope and therefore Mt. Begunjščica represent an important section for the understanding of Jurassic sedimentary evolution of Julian High. Jurassic beds are separated by at least one stronger fault, which divides them into the north and south block. In my master's thesis, I studied and described the Jurassic succession in the southern tectonic block of Mt. Begunjščica. A sedimentological section was logged and sampled for thin sections. I interpreted the sedimentary evolution of the Jurassic succession from detailed microfacial and biostratigraphic analysis. The succession is composed of four major lithostratigraphic units. The section begins with micritic limestones with biogenic debris and intermediate limestone breccias deposited in a deepened environment in the Early Jurassic. Manganese nodules and crusts are also present, indicating extremely slow sedimentation rates. After that irregular boundary follows and a short succession of shales, marls, cherts and limestones heavily enriched with manganese, with the lower part very likely deposited during the Early Toarcian oceanic anoxic event. The Toarcian sequence continues with condensed limestones of Ammonitico Rosso type, among which limestone breccias also occur, with manganese clasts and older rocks. Towards the top of the profile, the sequence changes more to the highly deformed limestone created by slumps. The age of these layers is questionable, they may still be of the Toarcian age, but it is also possible that they are Middle Jurassic in age and deposited above the stratigraphic gap. The section ends with alternating pelagic and turbiditic sediments, representing more calcareous development prior to radiolaritic deposits, which begin depositing at the northern block of the Mt. Begunjščica at the end of the Middle Jurassic but are not covered by the profile of the southern block anymore. The analysis of Jurassic beds on the south block of Mt. Begunjščica confirmed similarities with the section of the north block, which proves that the Jurassic sequence is repeated several times due to minor folds and a fault. The successions differ, in particular, in the thickness of the beds, indicating probably more submerged southern block already in the Jurassic. Today's fault is probably just a reactivated Mesozoic normal fault. The regional correlation shows that there are no comparable successions with Toarcian Ammonitico Rosso limestones in the narrower Julian Carbonate Platform, but they are typical for other paleogeographic units of the Southern Alps as well as other areas of the Jurassic passive margin of the Adriatic microplate.

V magistrskem delu so predstavljeni neptunski dajki, ki se pojavljajo v dachsteinskem apnencu zgornje triasne starosti. Raziskano območje se nahaja v severozahodnem delu Slovenije, na sedlu med Batognico in Krnom in naprej ob poti proti Gomiščkovemu zavetišču. Strukturno gledano pripada Južnim Alpam, natančneje Krnskemu pokrovu. V mezozoiku so celotne današnje Južne Alpe pripadale pasivnemu kontinentalnemu robu Tetide. Na omenjenem območju so v tem času prevladovale ekstenzijske napetostne razmere, ki so idealne za nastanek neptunskih dajkov. Ti so definirani kot zapolnitve praznih prostorov v starejši kamnini z mlajšim morskim sedimentom. Glede na geometrijo pojavljanja, ki je posledica nastanka praznih prostorov, smo neptunske dajke ločili na dve skupine, in sicer na monomiktne breče z mozaično teksturo in kaotične breče. Nastanek obeh skupin je vezan na lomne deformacije. Znotraj dachsteinskega apnenca so značilne korozijske votline, ki so nastale tik po odložitvi apnenca oziroma pred formiranjem neptunskih dajkov. Z detajlnimi mikroskopskimi raziskavami sedimenta, ki zapolnjuje prazne prostore, smo določili relativno časovno zaporedje zapolnitev korozijskih votlin in neptunskih dajkov. Začetek nastanka prvih praznih prostorov znotraj dachsteinskega apnenca je posledica zakrasevanja matične kamnine ob daljši izpostavljenosti subaerskim pogojem. Nastale so korozijske votlinice, ki so bile zapolnjene z alohtonim sedimentom transportiranim gravitacijsko ali z morskim tokom, delno pa s kalcitnim cementom. Zapolnitve so zgornjetriasne starosti. Ekstenzijska tektonika, ki je povročila nastanek ekstenzijskih razpok in prvih neptunskih dajkov, se je glede na naše raziskave na območju Krna začela zagotovo šele koncem jure. Nastale razpoke je zapolnila breča z ostrorobi klasti in rdečkastim vezivom, ki ponekod vsebuje kalpionele. Obstoja starejše faze odpiranja razpok, ki so jih opazili v predhodnih raziskavah, nismo potrdili. The master's thesis presents the neptunian dykes from the Upper Triassic Dachstein limestone. The studied area is located in the northwern Slovenia, in a saddle between Batognica and Mt. Krn and along the way to the Gomišček shelter. This area is structurally part of the Southern Alps, specifically the Krn Nappe. Mesozoic rocks of the Southern Alps formed at the passive continental margin of the Tethis Ocean. During this period the margin experienced extension, which is a favourable condition for the formation of neptunian dykes. These are defined as bodies of younger sediment filling fissures in rocks exposed on the sea floor. Based on the geometry of the neptunian dykes, they were classified into two groups: neptunian dykes with jigsaw structure and chaotic breccias. The geometry of the both groups is due to brittle deformation of the host rock. The corrosion voids appeared in the Dachstein limestone, which were formed after sedimentation of the limestone and before formation of the neptunian dykes. A detailed microscopic research of the sediment that fills the corrosion voids and the neptunian dykes helped in determination of the relative timing of the fillings. The first step is represented by karstification of the host rock. The voids were then filled with allochthonous sediment transported by gravity flows or water currents, and partly with calcite cement. According to our research, the active extension, which caused the formation of the extensional cracks, started at the end of Jurassic or later. The open cracks were filled with breccia, which is composed of sharp clasts in red matrix, which may contain calpionellids. We could not confirm the older phases of opening and extension observed in the previous studies.