Pub Date : 2024-02-07DOI: 10.3103/s0145875223050125
M. D. Shchekleina, P. Yu. Plechov, V. D. Shcherbakov, V. O. Davydova, I. N. Bindeman
Abstract—
This paper presents the results of a detailed petrological study of a continuous section of the Golygin ignimbrite, related to the Pauzhetka caldera-forming eruption (443 ± 8 ka BP). The continuous zoning of the studied sequence suggests that a large magmatic chamber, partially emptied during the eruption, was also zoned and had significant vertical dimensions. Our research included determining the bulk composition of rocks, studying samples of the Golygin ignimbrites in thin sections, and detailed studying of quartz and melt inclusions in it. The roof of the magmatic chamber was at a depth of about 5 km; amphibole and plagioclase crystalloclasts in rocks at the base of the sequence show evidence of formation in a more basic melt at a depth of 24 to 25 km. The composition of the magmatic melt reconstructed from melt inclusions in quartz from this sequence corresponds to medium-K rhyolites (wt %): SiO2 78.1–77.9, Al2O3 12.7–12, FeOt 0.8–0.1, MgO 0.1–0.0, CaO 1.0–0.2, K2O 4.3–3.8, Na2O 4.9–3.3, Cl2 0.1–0.2. Crystallization temperatures calculated for various minerals and their assemblages vary in the range 1009–784°С, which, together with estimates of formation depths of 25 km to 5 km, may reflect different stages of a crystallization of the magmatic melt, magma ascent and evolution in a relatively shallow chamber where it was slowly cooled and crystallized. The maximum water content of the magmatic melt during quartz crystallization was estimated in the range from 4.1 to 7.5 wt % H2O.
{"title":"The Petrology of the Golygin Ignimbrite (South Kamchatka)","authors":"M. D. Shchekleina, P. Yu. Plechov, V. D. Shcherbakov, V. O. Davydova, I. N. Bindeman","doi":"10.3103/s0145875223050125","DOIUrl":"https://doi.org/10.3103/s0145875223050125","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract—</h3><p>This paper presents the results of a detailed petrological study of a continuous section of the Golygin ignimbrite, related to the Pauzhetka caldera-forming eruption (443 ± 8 ka BP). The continuous zoning of the studied sequence suggests that a large magmatic chamber, partially emptied during the eruption, was also zoned and had significant vertical dimensions. Our research included determining the bulk composition of rocks, studying samples of the Golygin ignimbrites in thin sections, and detailed studying of quartz and melt inclusions in it. The roof of the magmatic chamber was at a depth of about 5 km; amphibole and plagioclase crystalloclasts in rocks at the base of the sequence show evidence of formation in a more basic melt at a depth of 24 to 25 km. The composition of the magmatic melt reconstructed from melt inclusions in quartz from this sequence corresponds to medium-K rhyolites (wt %): SiO<sub>2</sub> 78.1–77.9, Al<sub>2</sub>O<sub>3</sub> 12.7–12, FeOt 0.8–0.1, MgO 0.1–0.0, CaO 1.0–0.2, K<sub>2</sub>O 4.3–3.8, Na<sub>2</sub>O 4.9–3.3, Cl<sub>2</sub> 0.1–0.2. Crystallization temperatures calculated for various minerals and their assemblages vary in the range 1009–784°С, which, together with estimates of formation depths of 25 km to 5 km, may reflect different stages of a crystallization of the magmatic melt, magma ascent and evolution in a relatively shallow chamber where it was slowly cooled and crystallized. The maximum water content of the magmatic melt during quartz crystallization was estimated in the range from 4.1 to 7.5 wt % H<sub>2</sub>O.</p>","PeriodicalId":44391,"journal":{"name":"Moscow University Geology Bulletin","volume":"42 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-07DOI: 10.3103/s0145875223050058
E. A. Filimonova, E. I. Baranovskaya, M. A. Sokolovskaya, N. A. Kharitonova
Abstract
This paper estimates the deep heating temperature of the mineral waters of the Essentuki field by ionic geothermometers. The water is extracted from four productive aquifers (Danian–Selandian, Cenomanian–Maastrichtian, Aptian–Lower Albian, and Tithonian–Valanginian). The study shows that the most adequate deep temperatures, from 64 to 97°C, are provided by a SiO2 geothermometer; the Na–K geothermometer overestimates and the Mg–Li and chalcedony geothermometers underestimate this temperature. The water penetration depth is assessed at 1.2–1.8 km for the Danian–Selandian, Cenomanian–Maastrichtian, and Aptian–Lower Albian aquifers and at more than 2 km for the Tithonian–Valanginian aquifer.
{"title":"Estimation of the Real Subsurface Temperature for Mineral Water Circulated within the Essentuki Spa, Caucasian Mineral Waters Region","authors":"E. A. Filimonova, E. I. Baranovskaya, M. A. Sokolovskaya, N. A. Kharitonova","doi":"10.3103/s0145875223050058","DOIUrl":"https://doi.org/10.3103/s0145875223050058","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper estimates the deep heating temperature of the mineral waters of the Essentuki field by ionic geothermometers. The water is extracted from four productive aquifers (Danian–Selandian, Cenomanian–Maastrichtian, Aptian–Lower Albian, and Tithonian–Valanginian). The study shows that the most adequate deep temperatures, from 64 to 97°C, are provided by a SiO<sub>2</sub> geothermometer; the Na–K geothermometer overestimates and the Mg–Li and chalcedony geothermometers underestimate this temperature. The water penetration depth is assessed at 1.2–1.8 km for the Danian–Selandian, Cenomanian–Maastrichtian, and Aptian–Lower Albian aquifers and at more than 2 km for the Tithonian–Valanginian aquifer.</p>","PeriodicalId":44391,"journal":{"name":"Moscow University Geology Bulletin","volume":"15 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2024-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140888194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}