Mineraloška in petrološka analiza izbranih vulkanskih kamnin iz otoka Santorini : diplomsko delo

Mišjak, Maj (avtor), Vrabec, Mirijam (mentor), Zupančič, Nina (komentor)

Santorini je vulkanski otok, ki se nahaja na jugu Egejskega morja. Ta ima za sabo pestro zgodovino, med katero se je spremenil v veliko kaldero. Na otoku lahko opazimo bogato zbirko različnih vulkanskih kamnin. Z makroskopskim opazovanjem in mikroskopsko analizo z uporabo presevnega optičnega mikroskopa smo opravili pregled vzorcev, odvzetih z otoka Nea Kameni, ter lokacij Kokkari in Vlychada. Nekaj vzorcev smo naknadno pregledali s pomočjo vrstičnega elektronskega mikroskopa in na podlagi dobljenih rezultatov določili kemično sestavo izbranih mineralnih zrn v vzorcu. Z rentgensko praškovno difrakcijsko analizo smo določili mineralno sestavo in amorfno fazo posameznih vzorcev. Na podlagi geokemične analize smo kamnine razdelili v skupine na podlagi razmerja med vsebnostjo kremenice in deležem Zr/TiO2. Z optično mikroskopijo smo v vseh vzorcih določili hipohialinsko, afanitsko in oligofirsko strukturo. Vsi vzorci vsebujejo plagioklaze in piroksene, nekateri tudi olivine in nepresevne minerale. V vzorcih Nea Kameni in Kokkari se med plagioklazi pojavljata labradorit in bytownit, med pirokseni pa avgit, redkeje enstatit. Nekaj je olivinov, ki so bogatejši z magnezijem. Med plagioklazi v vzorcu Vlychada prevladuje andezin, med pirokseni je prisoten le enstatit. Rezultati geokemične analize so pokazali, da na otoku Nea Kameni prevladujejo rioliti ob manjši prisotnosti andezitov. Vzorci s Kokkari lokacije so pretežno rdeče-rjave barve in pripadajo andezitom in trahi-andezitom. Odvzete bele in lahke kamnine z bele plaže Vlychada smo uvrstili v skupino trahitov. Vulkanske kamnine z lokacije Nea Kameni smo pripisali najmlajši vulkanski dejavnosti, pri kateri je otok tudi nastal. Kamnine z bele plaže Vlychada so nastale med glavnima plinijskima izbruhoma, ob koncu prvega vulkanskega cikla. Andezitne kamnine z rdeče plaže Kokkari so kvartarne starosti in so nastale kot posledica začetka vulkanske dejavnosti na Santoriniju. Gre za pepelaste stožce, ki so nastali ob eksplozivnem izbruhu velikih vulkanskih bomb.

• Jezik: Slovenski jezik
• Ključne besede: Santorini, petrologija, vulkan, Nea Kameni, Kokkari, Vlychada
• Vrsta gradiva: Diplomsko delo/naloga
• Tipologija: 2.11 - Diplomsko delo
• Organizacija: NTF - Naravoslovnotehniška fakulteta
• Kraj izida: Ljubljana
• Založnik: M. Mišjak
• Leto izida: 2023
• Št. strani: XIII, 48 f.
• PID: 20.500.12556/RUL-147260
• UDK: 55
• COBISS.SI-ID: 160154371
• Datum objave v RUL: 28.06.2023

MIŠJAK, Maj, 2023, Mineraloška in petrološka analiza izbranih vulkanskih kamnin iz otoka Santorini : diplomsko delo [na spletu]. Diplomsko delo. Ljubljana : M. Mišjak. [Dostopano 26 april 2025]. Pridobljeno s: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=slv&id=147260

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Mineralogical and petrological characterization of selected volcanic rocks from the island of Santorini : diplomsko work

Izvleček

Santorini is a volcanic island located in the south of the Aegean Sea. It has a varied history behind it, during which it turned into a large caldera. A rich collection of various volcanic rocks can be seen on the island. With macroscopic observation and microscopic analysis using a scanning optical microscope, we performed an examination of the samples taken from the island of Nea Kameni and the locations of Kokkari and Vlychada. Some samples were subsequently examined with the help of a line electron microscope and, based on the obtained results, the chemical composition of the selected mineral grains in the sample was determined. X-ray powder diffraction analysis was used to determine the mineral composition and amorphous phase of individual samples. Based on the geochemical analysis, the rocks were divided into groups based on the ratio between the quartz content and the Zr/TiO2 ratio. Optical microscopy was used to determine the hypohyaline, aphanitic and oligophyric structure in all samples. All samples contain plagioclase and pyroxenes, some also contain olivine and non-replaceable minerals. In the samples from Nea Kameni and Kokkari, labradorite and bytownite occur among plagioclase, and augite and less commonly enstatite among pyroxenes. There are some olivines that are richer in magnesium. Among the plagioclases in the Vlychada sample, andesine dominates, while only enstatite is present among the pyroxenes. The results of the geochemical analysis showed that the island of Nea Kameni is dominated by rhyolites with a minor presence of andesites. The samples from the Kokkari location are predominantly red-brown in color and belong to andesite and trachy-andesite. The white and light rocks taken from the white beach of Vlychada were classified as trachytes. Volcanic rocks from the Nea Kameni location were attributed to the youngest volcanic activity, during which the island was formed. The rocks from the white beach of Vlychada were formed during the main Plinian eruptions, at the end of the first volcanic cycle. The andesite rocks of Kokkari Red Beach are of Quaternary age and were formed as a result of the onset of volcanic activity on Santorini. These are cinder cones that were formed during the explosive eruption of large volcanic bombs.

• Ključne besede: Santorini, petrology, volcano, Nea Kameni, Kokkari, Vlychada