Amonitna združba jurskih ploščastih apnencev v okolici Mežice in na Uršlji gori

• Main Author: Štruc, Miha
• Other Authors: Gale, Luka
• Format: Bachelor Thesis
• Language: Slovenian
• Published: 2020
• Subjects: Karavanke; spodnja in zgornja jura; amoniti; Ammonitico Rosso; podmorski plato; Karavanke Mts; Early and Middle Jurassic; ammonites; submarine plateau; Gora; Jura; Planktonic foraminifera
• Online Access: https://repozitorij.uni-lj.si/IzpisGradiva.php?id=120618; https://repozitorij.uni-lj.si/Dokument.php?id=135446&dn=; https://plus.si.cobiss.net/opac7/bib/33269507?lang=sl

Namen raziskovalne naloge je bil predstavitev izdankov jurskega apnenca tipa »Ammonitico Rosso« na območju Mežice (Jesenikov vrh) in Uršlje gore ter fosilnega materiala, ki je bil do sedaj tam najden in je v lasti zasebnih zbirateljev Ivana Ocepka in Matije Križnarja. Iz nabranih vzorcev sem izdelal zbruske, na podlagi katerih sem podal opise mikrofaciesov. V rezultatih sem opisal obe lokaciji ter amonitno združbo na Jesenikovem vrhu. Vrste, ki sem jih določil na Jesenikovem vrhu, so Psiloceras neurtigense, Lytoceras cf. cornucopisa, Harpoceras sp., Phylloceras sp., Hildoceras subserpentinium, Phylloceras heterohyllun, Dactylioceras cf. commune, Phlyseogrammoceras cf. dispansum, Fucinicera amalthe, Holcophylloceras calypso, Liparoceras sp., Paroniceras sternale, Hyperderoceras planarmatum, Hildoceras cf. sublevisioni, Hammatoceras speciosum, Hammatoceras speciosum, Arieticeras cf. retrorsicosta in Arietites sp. Združba kaže na toarcijsko starost. Od mikrofaciesov sta bila na Jesenikovem vrhu določena bioklastični packstone in krinoidni rudstone/floatstone, pod Uršljo goro pa bioklastični wackestone in bioklastični packstone. Okolje, v katerem so se odlagale kamnine, je bilo globljemorsko. V rdečih apnencih pod Uršljo goro so bile najdene tudi planktonske foraminifere, na podlagi katerih je bila določena srednje-jurska starost. S tem je dokazano, da je sedimentacija rdečih gomoljastih apnencev trajala vsaj od toarcija do srednje jure. The purpose of this research work is a presentation of Jurassic limestones of the »Ammonitico Rosso« type, outcropping in the area of Mežica (Jesenikov vrh) and Mt. Uršlja gora and the presentation of the fossil material, that was found there by private collectors Ivan Ocepek and Matija Križnar. Samples were collected at the sites and thin sections were made in order to determine the microfacies. The ammonites that were determined at Jesenikov vrh are Psiloceras neurtigense, Lytoceras cf. cornucopisa, Harpoceras sp., Phylloceras sp., Hildoceras subserpentinium, Phylloceras heterohyllun, Dactylioceras cf. commune, Phlyseogrammoceras cf. dispansum, Fucinicera amalthe, Holcophylloceras calypso, Liparoceras sp., Paroniceras sternale, Hyperderoceras planarmatum, Hildoceras cf. sublevisioni, Hammatoceras speciosum, Hammatoceras speciosum, Arieticeras cf. retrorsicosta and Arietites sp. The assemblage suggests Toarcian age. The microfacies types are bioclastic packstone and crinoid rudstone/floatstone. Under Uršlja gora the microfacies types bioclastic wackestone and bioclastic packstone were determined. The microfacies types suggest deposition in a deeper marine setting. In the limestone from locality Uršlja gora planktonic foraminifera were found, suggesting Middle Jurassic age. The time of sedimentation of the red nodular limestones is thus determined to be at least from the Toarcian to the Middle Jurassic.