Geomorphic indicators of tectonic activity at the Sava folds - Ljubljana basin transition, Tunjice hills, Central Slovenia

Pezdir, Valentina (author), Vrabec, Marko (mentor), Szekely, Balazs (comentor)

Tunjice Hills are located on the northwestern edge of Sava folds and represent a syncline structure with a fold axis in W - E direction. The Hills are composed of Miocene rocks. In thesis I investigate whether Quaternary tectonic activity occurs in the area, and whether active deformation can be attributed to the active folding of the Sava folds. I applied tectonic geomorphic methods to streams that flow over Tunjice Hills. I determined differences in sinuosity along the channel and investigated shapes of hypsometric curves and longitudinal stream profiles. I calculated values of hypsometric integrals and concavity parameters of maximal concavity and concavity factor and examined how far maximal concavity point is located from the source of the stream. The results show an increase in sinuosity when the rivers cross faults, at lithological changes, and in vicinity of confluence points. Most actively changed segments of streams are located in the westernmost stream and in central area of Tunjice Hills. Hypsometric curves for streams in the central part of Tunjice Hills have sigmoidal shape with possible tectonic activity in the lower part of the streams. From shape of hypsometric curve and values of hypsometric integral and concavity parameters, tectonic activity is apparent on the fault that runs along the Kamnik stream valley. Hypsometric curves, longitudinal stream profiles and concavity analysis showed that the eastern margin of the Hills is stable and in mature to old erosional stage which was also determined for a stream between westernmost Kamnik stream and central area. Tectonic activity is present on faults that belong to Sava fault zone. There is no indication of active deformation in Sava folds trend.

• Language: English
• Keywords: Tunjice Hills, tectonic geomorphology, rivers, tectonic activity, river sinuosity, hypsometric integral
• Work type: Master's thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2019
• PID: 20.500.12556/RUL-109800
• COBISS.SI-ID: 1526366
• Publication date in RUL: 08.09.2019

Secondary language

• Language: Slovenian
• Title: Geomorfni indikatorji tektonske aktivnosti na prehodu iz Posavskih gub v Ljubljansko kotlino v Tunjiškem gričevju

Abstract

Tunjiško gričevje se nahaja na severozahodnem robu Posavskih gub in predstavlja sinklinalno strukturo z osjo gube v smeri W - E. Gričevje sestavljajo miocenske kamnine. Namen naloge je določitev prisotnosti tektonske aktivnosti na območju Tunjiškega gričevja ter če so prisotne deformacije, ki potrjujejo enako aktivno gubanje kot v Posavskih gubah. V nalogi sem uporabila tektonsko geomorfološke metode na potokih, ki tečejo po območju Tunjiškega gričevja. Določevala sem spremembe v vijugavosti potokov, evidentirala obliko hipsometričnih krivulj in vzdolžnih profilov in izračunala vrednosti hipsometričnih integralov in parametrov konkavnosti, kot so maksimalna konkavnost in njena oddaljenost od izvira potoka ter konkavnostni faktor. Rezultati kažejo, da se vijugavost potokov poviša na območjih prelomov, sprememb v litologiji in v okolici sotočij. Največje spremembe v vijugavosti se nahajajo na najbolj zahodnem in osrednjem delu Tunjiškega gričevja. Hipsometrične krivulje potokov v osrednjem delu gričevja imajo sigmoidalno obliko in nakazujejo prisotnost tektonske aktivnosti v spodnjem delu potokov. Oblika hipsometrične krivulje, vrednosti hipsometričnega integrala in konkavnostnih parametrov kaže na aktivnost preloma v dolini potoka Kamnik. Hipsometrične krivulje, vzdolžni profili in analiza konkavnosti so pokazali da je vzhodni del gričevja v stabilnem stanju in v starejših erozijskih fazah, kar je značilno tudi za potok med najbolj zahodnim potokom Kamnik in osrednjem območjem. Tektonska aktivnost je vezana na prelome v coni Savskega preloma. Deformacij v smeri aktivnega gubanja Posavskih gub ni bilo zaznati.

• Keywords: Tunjiško gričevje, tektonska geomorfologija, reke, tektonska aktivnost, vijugavost rek, hipsometrični integral