Sedimentološka in stratigrafska analiza ladinijskih bazenskih razvojev na območju Kobiljega Curka pri Velikih Laščah

Vodnik, Primož (author), Rožič, Boštjan (mentor), Zupančič, Nina (comentor)

Na območju Rutarske planote izdanjajo predvsem anizijske in ladinijske kamnine, ki so prekrite s cordevolskim dolomitom. V veliki meri se pojavijo tudi vulkanoklastične kamnine, ki se izmenjujejo s plastnatimi apnenci in dolomiti. Del teh razvojev je bil poimenovan Mohorska formacija, ki naj bi se začela s cordevolskimi karbonati in nato prešla v črne mikritne in sparitne apnence lagunskega faciesa. Nanje so odloženi tufi, ki se končajo z drobnozrnatim konglomeratom in rdečimi klastiti, ki postopoma preidejo v glavni dolomit. Med tečajem geološkega kartiranja študentov geologije z Naravoslovnotehniške fakultete Univerze v Ljubljani v letih 2016 in 2017 se je izkazalo, da na obravnavanem območju obstajata dva vzporedna razvoja: platformski, ki ustreza Mohorski formaciji, in bazenski, ki na tej lokaciji do sedaj še ni bil opisan. Starost bazenskih kamnin je bila za namene te raziskave s pomočjo konodontov določena za ladinijsko. V okviru magistrskega dela sem posnel in preučil 233 m sedimentološkega profila. Ugotovil sem, da gre za spremembe razvojev, od takih, ki kažejo plitvomorsko okolje, v razvoje, značilne za bazensko okolje s piroklastiti, glinavci in turbiditnimi sedimenti, nato razvoje, ki kažejo progradacijo karbonatne platforme. V profilu sta jasno izraženi vsaj dve fazi poglobitve in progradacije, ki sta bili povzročeni s tektonskimi premiki. Preučil sem tudi vulkanoklastične kamnine, ki kažejo kislo do srednjo sestavo. Ugotovil sem, da gre za ladinijski razvoj manjšega bazena, ki ga je spremljala eksplozivna vulkanska aktivnost. Začel je nastajati ob razpadu Slovenske karbonatne platforme v aniziju, nato pa je bil podvržen hitremu zasipavanju in je bil verjetno zapolnjen že pred koncem ladinija.

• Language: Slovenian
• Keywords: anizij, ladinij, trias, konodonti, Rutarska planota, Velike Lašče, stratigrafija, karbonati, vulkanoklastiti, bazenski sedimenti
• Work type: Master's thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2020
• PID: 20.500.12556/RUL-117110
• COBISS.SI-ID: 22495747
• Publication date in RUL: 24.06.2020

Secondary language

• Language: English
• Title: Sedimentological and stratigraphical analysis of Ladinian basinal succession from the Kobilji Curek area near Velike Lašče

Abstract

On Rute plateau, mostly Anisian and Ladinian rocks appear, which are usually covered with Cordevolian dolomites. Vulcanoclastic rocks that interbed with platy limestones and dolostones are common as well. A part of those successions was named Mohorje formation. Its base is formed by Cordevolian carbonates, upon which black micritic and sparitic limestone beds of lagunal facies are overlain. Then, tuffs are lying uniformly on top and end in fine-grained conglomerate and red clastic rocks. The conglomerate gradually transits into Main Dolomite. During courses of geological mapping for students of geology from Faculty of Natural Sciences and Engineering of University of Ljubljana in years 2016 and 2017, two parallel succession developments were distinguished: a platform succession, similar to Mohorje formation; and an undescribed basinal succession. The age of basinal sediments was determined with conodont assemblages and set to Ladinian. In my master’s work, I logged a 233 m long sedimentological cross-section. Volcanoclastic rocks were studied as well, revealing acidic to intermediate affinities. The succession evolves from shallow marine to basinal, with volcanoclastic rocks, claystones and debris-flow beds, into which a carbonate platform progrades afterwards. The cross-section exhibits two phases of tectonically driven deepening and progradation. I concluded it is a Ladinian evolution of a smaller basin, accompanied with explosive volcanic activity. It began deepening during the Anisian, with disintegration of Slovenian carbonate platform and then quickly filled with sediment, probably before the end of Ladinian.

• Keywords: Anisian, Ladinian, Triassic, conodonts, Rute plateau, Velike Lašče, stratigraphy, carbonates, vulcanoclastic rocks, basinal sediments