Sedimentologija in stratigrafija amfiklinskih plasti Slovenskega bazena

Pristavec, Maja (author), Rožič, Boštjan (mentor), Gale, Luka (comentor)

Namen magistrske naloge je bil stratigrafski in sedimentološki opis dveh profilov zgornjetriasnih (karnijskih) amfiklinskih plasti. Profil Martinj vrh se nahaja južno od Železnikov in se nahaja v Škofjeloškem hribovju. Profil Poče se nahaja na severnem pobočju nad vasjo Poče in je del Cerkljanskega hribovja. Profil Martinj vrh se nahaja na južnem robu Rutarskega pokrova, profil Poče pa znotraj Podmelškega pokrova; oba sta del večjega Tolminskega pokrova. V profilu Martinj vrh je bilo podrobneje preučenih 50,5 m kamninskega zaporedja, v profilu Poče pa 39 m. Določene so bile makroskopske in mikroskopske sedimentološke značilnosti kamninskega zaporedja. V profilu se v različnih razmerjih izmenjujejo siliciklastične in karbonatne kamnine. Profila se med seboj razlikujeta glede na zrnavost siliciklastičnih horizontov. Mešano zaporedje kaže na karbonatno hemipelagično sedimentacijo, klastične in kalkarenitne plasti pa kažejo na sedimentacijo z gravitacijskimi tokovi. Sinsedimentni prelomi in gube v profilih so posledica plazenja delno konsolidiranega materiala s šelfnega pobočja v bazensko okolje. Glinavce gradijo slednji minerali: kremen, ortoklaz, muskovit, ilit, albit, kaolinit, kalcit in dolomit. Elementarna analiza je pokazala, da so glavni elementi v kamnini silicij, aluminij in kalcij, sledijo jim kalij, natrij, magnezij, železo in titan. Podrejeno se pojavljajo žveplo, fosfor in mangan. Določena je bila konodontna in foraminiferna združba. Z mikrofacielno analizo je bilo znotraj profilov določenih devet karbonatnih mikrofaciesov in šest klastičnih. Izvedena je bila primerjava in korelacija z že do sedaj objavljenimi deli o amfiklinskih plasteh in s klastičnimi kamninami, ki so se odlagale na južno ležeči Dinarski karbonatni platformi. Znotraj mikrofaciesnih skupin so bile opažene številne diagenetske spremembe: mikritizacija, okremenitev, karbonatizacija in nastanek različnih karbonatnih cementov, kompakcija, dolomitizacija in dedolomitizacija.

• Language: Slovenian
• Keywords: amfiklinske plasti, Južne Alpe, Tolminski pokrov, Rutarski pokrov, Podmelški pokrov, Slovenski bazen, mešano klastično- karbonatno zaporedje, karnij, gravitacijskih tokovi, hemipelagična sedimentacija
• Work type: Master's thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2024
• Publication date in RUL: 06.09.2024

Secondary language

• Language: English
• Title: Sedimentology and stratigraphy of Amphiclina beds from Slovenian basin

Abstract

The aim of the master's thesis was the stratigraphic and sedimentological description of two sedimentary outcrops of Upper Triassic Amphiclina beds located in the Western Pre-Alpine Mountains. The Martinj Vrh outcrop is located south of Železniki and is part of the Škofjeloško Hills. The Poče outcrop is located on the northern slope above the village of Poče and is part of the Cerkljansko Hills. The Martinj Vrh outcrop is located in the southernmost partof the Rut Subnappe, and the Poče outcrop is located within the Podmelec Subnappe, which are both part of the larger Tolmin Nappe. In total 50.5 m of the rock sequence were studied in detail in the Martinj Vrh section and 39 m in the Poče section. The macroscopic and microscopic sedimentological characteristics of the rock sequence were determined. Siliciclastic and carbonate rocks alternate in different ratios in the sections. The outcrops differ in the grain size of the siliciclastic horizons. The mixed sequence indicates carbonate hemipelagic sedimentation, while the siliciclastic and calcarenitic layers indicate sedimentation by gravity currents. Synsedimentary faults and folds in the outcrops are the result of slumping of partially consolidated material from the shelf slope into the basin environment. The minerals that form the claystones are quartz, orthoclase, muscovite, illite, albite, kaolinite, calcite and dolomite. Elemental analysis shows that silicon, aluminium and calcium are the main elements within the rock, followed by potassium, sodium, magnesium, iron and titanium. Sulfur, phosphorus and manganese occur in minor amounts. Nine carbonate microfacies and six siliciclastic microfacies were determined by microfacies analysis. Comparison and correlation were made with previously published work on the Amphiclina beds and with siliciclastic rocks deposited on the south-lying Dinaric Carbonate Platform. A number of diagenetic changes have been observed within the microfacies groups: micritization, silicification, carbonatization and the formation of different carbonate cements, compaction, dolomitization and dedolomitization.

• Keywords: Amphiclina beds, Southern Alps, Tolmin Nappe, Rut Subnappe, Podmelec Subnappe, Slovenian Basin, mixed siliciclastic-carbonate sequence, Carnian, gravity currents, hemipelagic sedimentation