Geološka zgradba in tektonika severozahodnega dela Kamniških Alp

Dolžan, Erazem (author), Vrabec, Marko (mentor)

Severozahodni del Kamniških Alp so klasično interpretirali kot narivni pokrov, vendar v kasnejših raziskavah na širšem območju Kamniško-Savinjskih Alp narivanje v takšnem obsegu ni bilo potrjeno. Dobra razgaljenost območja omogoča uporabo daljinskih metod za študij strukture. Iz zračnih posnetkov sem s fotogrametričnimi metodami izdelal teksturiran 3D model površja, ki sem ga uporabil za strukturne interpretacije, nato pa sem te interpretacije preverjal in dopolnjeval s terenskim delom. Podatke iz daljinskih metod in terenskega dela sem združil v 3D strukturnem modelu območja. Pri svojem delu sem se ukvarjal z obstojem in geometrijo narivne ploskve, ki izdanja na zahodnih pobočjih Kočne. Potrdil sem njen obstoj in ugotovil, da vpada približno 8° proti vzhodu, nisem pa našel neposrednih dokazov, da je ob ploskvi dejansko potekalo narivanje. Poimenoval sem jo Kočenska ločilna ploskev (KLP). Ploskev bi glede na obliko gube v krovnini lahko predstavljala bodisi nariv bodisi pa položnejši (spodnji) del listričnega normalnega preloma. V krovnini KLP sem kartiral zgornjetriasno zaporedje kamnin, v katerem sem največ pozornosti posvetil horizontu Martuljškega apnenca, ki predstavlja dober reperni horizont za sledenje premikom ob prelomih. Ta horizont je proti severovzhodu spuščen ob seriji normalnih prelomov za katere sklepam, da spuščajo tudi KLP, zato na vzhodnih delih območja ne izdanja. Pri svojem delu sem na tem območju določil 4 do 5 tektonskih faz: F1) ekstenzija v smeri SZ-JV in nastanek normalnih prelomov s prvotnim vpadom proti SV in JZ (v to fazo uvrščam tudi morebitni normalni premik ob KLP); F2) ekstenzija v smeri Z-V in normalni prelomi s prvotnim vpadom proti J in S; ?F3) narivanje ob KLP (v primeru da KLP predstavlja narivno ploskev); F4) transpresijsko nagibanje ozemlja in F5) zmičnotektonska kompresija v smeri SZ-NV in tenzija prečno na to smer. Zadnji fazi ustrezajo normalni prelomi z vpadom proti SV, zmični prelomi v smeri JZ-SV in reverzni prelomi v smeri Z-V.

• Language: Slovenian
• Keywords: Geomodeliranje, fotogrametrija, narivanje, zgornji trias, južne Alpe
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-91524
• Publication date in RUL: 19.04.2017

Secondary language

• Language: English
• Title: Structure and Tectonics of the North-Western Part of the Kamnik Alps

Abstract

The north-western part of Kamnik Alps was originally interpreted as a thrust sheet, but subsequent research in the wider area of the Kamnik-Savinja Alps did not confirm the existence of this thrust in the previously assumed extent. In this area, good exposure enables the use of remote sensing methods in structural studies. I used photogrammetric reconstruction to build a textured 3D model of the ground surface from aerial photographs. The model served as a base for structural interpretation, which was then improved with field data. Both remote sensing and field data were used to build a 3D structural model of the area. My work confirmed the existence of a detachment surface on the western slopes of Mt. Kočna, which dips about 8° towards east, but no direct evidence for thrusting was found. Alternatively, this detachment could represent a low-angle normal fault, perhaps a lower section of a listric normal fault. It was named the Kočna Detachment Surface (KDS). In the hanging wall of the KDS, an Upper-Triassic stratigraphic sequence was mapped. Special attention was given to tracing the Martuljek limestone horizont, which represents a good marker for determination of fault displacements. The Martuljek horizont is successively lowered towards NW along normal faults, which most likely displace the KDS as well, which explains why the KDS does not outcrop in the eastern parts of the area. In the area, 4 to 5 tectonic phases were determined in this study: F1) NW-SE extension along normal faults originally dipping NE and SW. Slip on KDS also belongs to this phase, if assuming normal displacement. F2) W-E extension along normal faults originally dipping N and S; ?F3) Thrusting along the KDS (if assuming reverse displacement on KDS); F4) Transpressive tilting, and F5) NW-SE compression with NE-SW extension in strike-slip tectonic regime. In this phase, normal faults dipping towards NE, strike-slip faults in SW-NE direction and reverse faults in W-E direction were activated.

• Keywords: Geomodelling, photogrammetry, thrusting, upper Triassic, Southern Alps