Crystallization conditions of plagioclase in volcanic complexes of Sulawesi island, Pacific Ocean
Author:
Kotlyarov A.V.1, Dmitrieva N.V.2, Simonov V.A.2, Safonova I.Yu.3, Karmanov N.S.2, Nizametdinov I.R. Nizametdinov2
Affiliation:
1. Institute of Geology and Mineralogy, SB RAS, pr. Akademika Koptyuga 3, Novosibirsk, 630090 Russia; kotlyarov@igm.nsc.ru 2. Institute of Geology and Mineralogy, SB RAS, pr. Akademika Koptyuga 3, Novosibirsk, 630090 Russia 3. Institute of Geology and Mineralogy, SB RAS, pr. Akademika Koptyuga 3, Novosibirsk, 630090 Russia; Southwest Jiaotong University, Xi’an Road 999, Chengdu, 611756 China
Abstract
Mineralogical and thermobarogeochemical studies allowed us to reveal the crystallization conditions of plagioclase in volcanic complexes of Sulawesi Island (Pacific Ocean). The composition of plagioclases indicates the presence of three types of melts, which were involved in the formation of plagioclase phenocrysts in basalts, andesites and dacites, as well as crystallites in the groundmass of andesites and dacites. The analysis of glasses of heated melt inclusions in plagioclase indicates the involvement of two contrasting melts (mafic and felsic) in crystallization of phenocrysts. At the final stages of volcanic processes, plagioclase in matrix of andesites and dacites formed from another felsic melts with maximum alkali content. The presence of primary syngenetic melt and fluid inclusions in plagioclase phenocrysts indicates the phase separation of felsic magmas, which led to the crystallization of feldspar phenocrysts of different composition during the formation of dacites. Computational modeling in a program (Putirka, 2008) based on the composition of plagioclases, glasses of heated inclusions and glasses from the groundmass allowed us to estimate the crystallization temperatures of feldspar phenocrysts in basalts (1160–1120 ?С), andesites (930–890 ?С) and dacites (1020–950 ?С), as well as the feldspar microcrystals in the groundmass of andesites (875–810 ?С) and dacites (890–850 ?С).
Keywords: crystallization conditions, plagioclase, melt inclusions, Sulawesi Island, Pacific Ocean.
Publisher
South Urals Federal Research Center for Mineralogy and Geoecology of the Urals Branch of the RAS
Subject
Orthopedics and Sports Medicine,Surgery,Developmental and Educational Psychology,Parasitology,Organizational Behavior and Human Resource Management,Applied Psychology,Soil Science,Plant Science,Soil Science,Plant Science,Soil Science,General Medicine,Philosophy,General Physics and Astronomy,Nuclear and High Energy Physics
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