Experimental study of pargasite NaCa2 (Mg4Al)[Si6Al2O22](OH)2 stability at T = 1000–1100°C and the pressure is up to PH2O = 5 kbar-Reference-Cited by-同舟云学术

Experimental study of pargasite NaCa2 (Mg4Al)[Si6Al2O22](OH)2 stability at T = 1000–1100°C and the pressure is up to PH2O = 5 kbar

Published:2024-09-06 Issue:2 Volume:69 Page:49-65
ISSN:0016-7525
Container-title:Геохимия
language:
Short-container-title:Geohimiâ

Author:

Devyatova V. N.¹,Nekrasov A. N.¹,Bondarenko G. V.¹

Affiliation:

1. D.S. Korzhinskii Institute of Experimental Mineralogy of Russian Academy of Sciences

Abstract

The paper presents materials on experimental study of pargasite stability. On the example of calcic amphibole, experimental modeling of the processes occurring in the conditions of volcanic hearth at pressures up to 5 kbar was carried out. The phase diagram of pargasite was clarified. The occurring reactions and their parameters are revealed. Based on the experimental data obtained, the stability of pargasite is controlled by three reactions. The first reaction takes place in the area of low water pressure less than 1 kbar – dehydration reaction:Prg = Fo + Sp + Di + Ne + An +H2O. The second reaction takes place in the area of water pressure more than 1.2-1.5 kbar and temperature around 1100°C. Pargasite decomposition is controlled by incongruent melting:Prg = Fo + Sp +{Di+Ne +An}L+H2O. The third reaction takes place in the same pressure range as the previous one, but at lower temperatures ~1050°C. This reaction determines the pargasite liquidus in the melt and is related to the interaction between the amphibole and the coexisting melt:Prg + L= Fo + Sp + Di +{Ne +Pl}L+H2O.Presumably, the activity of the melt silicaaSiO2has the greatest impact on the pargasite liquidus.

Publisher

The Russian Academy of Sciences

Reference56 articles.

1. Гиорсо М. С., Кармайкл И. С.Е. (1992) Моделирование магматических систем: петрологическое приложение. Термодинамическое моделирование в геологии (минералы, флюиды, расплавы) Ред.: Кармайкл И., Ойгстер Х. М.: Мир. 487–518.

2. Жариков В. А. (1976) Основы физико-химической петрологии. М.: Изд-во МГУ, 420 с.

3. Кадик А. А., Максимов А. П., Иванов Б. В. (1986) Физико-химические условия кристаллизации и генезис андезитов (на примере Ключевской группы вулканов). М.: Наука, 158 с.

4. Колосков А. В., Ананьев В. В., Пузанков М. Ю. (2014) Амфибол в четвертичных гавайитах Кекукнайского вулканического массива (Камчатка) как показатель декомпрессионной эволюции расплавов повышенной щелочности. Записки ВМО. (2), 94–115.

5. Нагаев Э. Л. (1992) Малые металлические частицы. Успехи физических наук. 162(9), 49–124.