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GEOREF RECORD

Phase formation and diamond crystallization in carbon-bearing ultrapotassic carbonate-silicate systems

A. F. Shatsky, Yu. M. Borzdov, A. G. Sokol and Yu. N. Pal'yanov
Phase formation and diamond crystallization in carbon-bearing ultrapotassic carbonate-silicate systems
Russian Geology and Geophysics (October 2002) 43 (10): 889-901

Abstract

Diamond crystallization and character of phase formation in the systems K (sub 2) CO (sub 3) -C, K (sub 2) CO (sub 3) -SiO (sub 2) -C, and K (sub 2) CO (sub 3) -Mg (sub 2) SiO (sub 4) -C were studied at 6.3 GPa and 1650 degrees C for 40 hours using the multianvil split-sphere equipment. The SiO (sub 2) /K (sub 2) CO (sub 3) and Mg (sub 2) SiO (sub 4) /K (sub 2) CO (sub 3) ratios were chosen as variable parameters. The degree of graphite-to-diamond transformation and rate of diamond growth on seeds have been determined as a function of these ratios. Composition domains have been revealed in which spontaneous diamond nucleation and seeded growth occur. As the concentrations of silica and forsterite in the systems K (sub 2) CO (sub 3) -SiO (sub 2) -C and K (sub 2) CO (sub 3) -Mg (sub 2) SiO (sub 4) -C, respectively, increase to 10 wt.%, the diamond formation becomes more intense. Given a further increase in contents of SiO (sub 2) or Mg (sub 2) SiO (sub 4) , this intensity gradually decreases until the complete termination of spontaneous nucleation and seeded diamond growth. The conditions were created under which diamond was crystallized from a potassium carbonate-silicate melt, including the main components of mantle-derived ultrapotassic fluxes, together with coesite in the system K (sub 2) CO (sub 3) -SiO (sub 2) -C and with forsterite in the system K (sub 2) CO (sub 3) -Mg (sub 2) SiO (sub 4) -C.


ISSN: 1068-7971
Serial Title: Russian Geology and Geophysics
Serial Volume: 43
Serial Issue: 10
Title: Phase formation and diamond crystallization in carbon-bearing ultrapotassic carbonate-silicate systems
Affiliation: Russian Academy of Sciences, Siberian Branch, Institute of Mineralogy and Petrography, Novosibirsk, Russian Federation
Pages: 889-901
Published: 200210
Text Language: English
Publisher: Novosibirsk State University, Novosibirsk, Russian Federation
References: 40
Accession Number: 2023-004341
Categories: Igneous and metamorphic petrologyMineralogy of non-silicates
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Country of Publication: Russian Federation
Secondary Affiliation: GeoRef, Copyright 2023, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 2023
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