Geokemične lastnosti kamnin in tal zgornjega toka Mislinje : diplomsko delo

Omejec, Damjana (author), Zupančič, Nina (mentor), Lojen, Sonja (comentor), Rogan Šmuc, Nastja (member of the commission for defense), Dolenec, Matej (member of the commission for defense)

Izotopi predstavljajo ključno orodje za preučevanje izvora, napajanja in interakcij vode v okolju. Za pridobitev osnovnega geokemičnega ozadja na območju Mislinjskega grabna smo analizirali izotopsko sestavo organskega ogljika (δ13Corg) in dušika (δ15N) tal ter rezultate dopolnili z mineralno in elementno sestavo tal in kamnin. Kamnine sem makroskopsko opisala in ocenila deleže posameznih mineralov. Mineralno sestavo gnajsa (K1), amfibolita (K3) in pripadajočih tal (T1; T3) smo analizirali z XRD. Kemično sestavo vseh vzorcev smo preverili z XRF. Izotopsko sestavo tal smo izmerili z masno spektroskopijo. Tla na gnajsu (T1) so ohranila podobno mineralno sestavo kot kamnina (K1): prisotni so kremen, K-glinenci, plagioklazi, sljude in klorit. V amfibolitu (K3) se rogovača, plagioklaz, kremen, epidot, klorit in muskovit, v tleh (T3) muskovit, klorit, rogovača, kremen, plagioklazi in epidot. Največjo variabilnost med vzorci istega tipa kamnine kažejo blestniki (K2c, K2d, K5), predvsem po vsebnostih Al2O3 in K2O. Felzične kamnine (gnajs, blestnik, dacit, granodiorit, diaftorit) imajo v primerjavi z kamninami z bolj mafično sestavo (amfibolit, andezit) višje vsebnosti SiO2, Al2O3, K2O, Ba, Cr, Mo, Pb, Rb, Zn in Zr ter nižje Fe2O3, MgO, CaO, Na2O, TiO2, P2O5, MnO, As, Cu in Sn. Kemične razlike med skupinama so večje kot razlike med tlemi nastalimi na njih. Kljub temu lahko glede na vsebnosti SiO2, Al2O3, Fe2O3, MgO, CaO, Zr, Ni, Rb, Sc, Sr, Zn sklepamo na tip matične podlage. Mineralna in geokemična sestava tal ni popolnoma enaka sestavi matične podlage. Tla so bogata z organsko snovjo (do 10 % Corg). Na območju prevladujejo C3 rastline (δ 13C je med -25 in -27 ‰). Vrednost izotopske sestave dušika se v vzorcih tal pojavlja v razponu od -0,21 do +2,71 ‰.

• Language: Slovenian
• Keywords: kemična sestava, geokemija, izotopska sestava, XRF, XRD
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Place of publishing: Ljubljana
• Publisher: D. Omejec
• Year: 2026
• Number of pages: XII, 55 str.
• PID: 20.500.12556/RUL-188587
• UDC: 55
• COBISS.SI-ID: 301073155
• Publication date in RUL: 24.09.2026

Secondary language

• Language: English
• Title: Geochemical properties of rocks and soils of Mislinja river upper course : diploma work

Abstract

Isotopes represent a key tool for studying the origin, recharge, and interaction of water in the environment. To establish a basic geochemical background of the Mislinjski graben area, we analyzed the isotopic composition of organic carbon (δ13Corg) and nitrogen (δ15N) and supplemented the results with data on the mineral and elemental composition of the soils and rocks. I described the rocks macroscopically and estimated the proportions of individual minerals. The mineral composition of gneiss (K1), amphibolite (K3), and the associated soils (T1; T3) were analyzed using XRD. The chemical composition of all samples were determined with XRF, while the isotopic composition of the soils was measured using mass spectrometry. The soil overlying the gneiss (T1) retained a mineral composition similar to that of the parent rock (K1): quartz, K-feldspars, plagioclases, micas, and chlorite are present. The amphibolite (K3) contains hornblende, plagioclase, quartz, epidote, chlorite, and muscovite, whereas the soil (T3) contains muscovite, chlorite, hornblende, quartz, plagioclases, and epidote. Among samples of the same rock type, the micaschists (K2c, K2d, K5) exhibit the greatest variability, particularly regarding their Al2O3 and K2O content. Compared to rocks with a more mafic composition (amphibolite, andesite), felsic rocks (gneiss, mica schist, dacite, granodiorite, diaphtorite) exhibit higher contents of SiO2, Al2O3, K2O, Ba, Cr, Mo, Pb, Rb, Zn, and Zr, and lower contents of Fe2O3, MgO, CaO, Na2O, TiO2, P2O5, MnO, As, Cu, and Sn. Chemical differences between the rock groups are greater than the differences between the soils formed upon them. Nevertheless, the type of parent material can be inferred from the contents of SiO2, Al2O3, Fe2O3, MgO, CaO, Zr, Ni, Rb, Sc, Sr, and Zn. The mineral and geochemical composition of the soil is not identical to that of the parent material. The soils are rich in organic matter (up to 10 % Corg). C3 plants predominate in the area (δ13C ranges from -25 to -27 ‰). Nitrogen isotopic composition values in the soil samples range from -0.21 to +2.71 ‰.

• Keywords: chemical composition, geochemistry, isotopic composition, XRF, XRD