Petrochemistry and mineralogy of pumice from the Sarychev Peak Volcano, Matua Island, Central Kuril Island

• Published in: Izvestija vyss̆yh uc̆ebnyh zavedenij. Geologija i razvedka no. 2; pp. 57 - 67
• Main Authors: Okrugin, V. M., Skilskaia, E. D., Moskaleva, S. V.
• Format: Journal Article
• Language: English; Russian
• Published: Sergo Ordzhonikidze Russian State University for Geological Prospecting 17.10.2022
• Subjects: амфибол; вулкан пик сарычева; курилы; пемза; плагиоклаз; стекло
• ISSN: 0016-7762; 2618-8708
• DOI: 10.32454/0016-7762-2022-64-2-57-67

Background. The article presents the first results of a mineralogical and petrographic study of the pumice of the Sarychev Peak volcano, Matua island, the Central Kuril islands. Aim. To reconstruct the compositions of magmatic melts of a caldera-forming eruption of the proto-Matua volcano. Materials and methods. The main research methods included an X-ray fluorescence spectral analysis to determine the content of petrogenic, rare and trace elements, as well as an electron-probe microanalysis to study variations in the chemical composition of mineral inclusions of pumice. Results and conclusion . According to the content of SiO 2 and the sum of alkalis, the composition of pumice varies from andesibasaltes (SiO 2 = 55.94 wt.%) to dacites (SiO 2 = 67.70 wt.%). According to the content of K 2 O, pumice can be classified as a moderate-potassium series of rocks. The inclusion minerals represented by plagioclase, amphibole, apatite and Fe-Ti oxides were crystallized at the same time from a water-saturated magmatic melt at a pressure of about 1.5–2.2 kbar. The igneous melt was enriched with volatile components of H 2 O, CO 2 , S, F and Cl.