Sedimentološka analiza srednjetriasnih breč izpod Vernarja v Julijskih Alpah

Kadivec, Katarina (avtor), Gale, Luka (mentor), Celarc, Bogomir (komentor)

V okviru magistrskega dela je bilo raziskano triasno stratigrafsko zaporedje pod Vernarjem (2225 m) v Julijskih Alpah. Le te so strukturno del Južnih Alp. Na vzhodni strani Vernarja, nekaj 100 m pod vrhom, leži horizont Ukovških breč. Debelina horizonta se bočno spreminja od 30 do 150 m. Vzporedno z brečami se nahajajo rdeči gomoljasti apnenci. Nad horizontom breč in rdečih apnencev leži masiven platformni apnenec Schlernske formacije. V magistrski nalogi sem natančneje opisala stratigrafsko zaporedje na vzhodni strani Vernarja, znotraj katerega se nahajajo Ukovške breče. Le te so v večjem delu sestavljene iz karbonatnih klastov. Njihova analiza kaže, da so apnenci, ki gradijo klaste breč, večinoma nastajali na karbonatni platformi in so bili kasneje kot klasti erodirani z relativno dvignjenega bloka. S pomočjo fosilov, predvsem foraminifer, sem določila, da so klasti anizijske starosti. Prisotni so tudi vulkanski klasti, ki so bili domnevno erodirani iz riolitov, ki so nastali z izlivi lave. Kot tanjše vmesne plasti se pojavi tudi karbonatni peščenjak. Na podlagi analize rdečih gomoljastih apnencev in mikrofosilov v njih ter s primerjavo z že znanimi primeri, sem ugotovila, da so se ti odložili v poznem aniziju, v plitvomorskem okolju. Analizirala sem tudi vzorce masivne Schlernske formacije. Raziskave v sklopu magistrske naloge so razsvetlile sledečo sedimentarno evolucija območja: 1) zaradi tektonske aktivnosti je konec anizija nastal polgraben, ki se je zapolnil s sedimenti Ukovške breče; 2) na robu klančine je, deloma lateralno z odlaganjem breč, potekala sedimentacija rdečih gomoljastih apnencev; 3) za tem je sledila karbonatna produkcija na ladinijski karbonatni platformi. Razvoji se dobro korelirajo tudi z ostalimi že opisanimi primeri iz Julijskih Alp (Prisojnik), Kamniško-Savinjskih Alp (Ute, Križevnik), Karnijskih Alp, Balatonskega višavja, Zunanjih Dinaridov in Dolomitov.

• Jezik: Slovenski jezik
• Ključne besede: polgraben, trias, anizij, ladinij, Ukovška breča, foraminifere, sedimentologija, stratigrafija, Julijske Alpe
• Vrsta gradiva: Magistrsko delo/naloga
• Organizacija: NTF - Naravoslovnotehniška fakulteta
• Leto izida: 2020
• PID: 20.500.12556/RUL-122915
• COBISS.SI-ID: 43424515
• Datum objave v RUL: 16.12.2020

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Sedimentological analysis of middle triassic breccias below Mt. Vernar in Julian Alps

Izvleček

In the context of the master 's thesis the Triassic stratigraphic sequence on Mt. Vernar (2225 m) was investigated. Mt. Vernar is located in the Julian Alps, which are structurally (tectonically) part of the Southern Alps. About 100 m below the summit on the eastern side of the mountain is the horizon of the Uggovitz breccia. The thickness of the horizon varies laterally from 30 to 150 m. Laterally with breccias occurs red nodular limestone. Above the breccias and the red nodular limestone is a massive platform limestone of the Schlern Formation. In the thesis, the detailed stratigraphic sequence of the eastern side of Mt. Vernar is described. The Uggovitz breccia occurs in this sequence. The composition of the clasts was described in detail. The breccia consists mainly of carbonate clasts. Their analysis showed that they were mostly formed as limestones on the carbonate platform and were later eroded as clasts from a relatively elevated block. Based on the fossils, mainly foraminifera, we concluded that the clasts are of Anisian age. Volcanic clasts eroded from rhyolite lava are also visible. Carbonate sandstone occurs as thin layers between breccia beds. By analyzing the overlying red nodular limestones and the fossils contained therein and comparing them with other known cases, we found that the limestone was deposited in a shallow water marine environment. By analyzing samples from the uppermost massive Schlern Formation we found that carbonate production continued on the Ladinian platform after the half-graben was filled with sediments. Based on an analysis of the sediments, it is interpreted that a half-graben was formed as a consequence of the extension at the end of the Anisian and filled with sediments of the Uggovitz breccia. Thereafter, the shallow water sedimentation of red nodular limestone continued after that carbonates were produced on the relatively uplifted Ladinian carbonate platform. The stratigraphic succession fromVernar is similar to other known and described cases from the Julian Alps (Prisojnik), Kamnik-Savinja Alps (Ute, Križevnik), Carnian Alps, Balaton Highlands, the outer Dinarides and the Dolomites.

• Ključne besede: Half-graben, Triassic, Anisian, Ladinian, Uggovitz breccia, foraminifera, sedimentology, stratigraphy, Julian Alps