Grain-boundary migration of quartz during annealing experiments at high temperatures and pressures, with implications for metamorphic geology

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Authors:Masuda, T.; Morikawa, T.; Nakayama, Y.; Suzuki, S.
Author Affiliations:Primary:
Shizuoka University, Institute of Geosciences, Shizuoka, Japan
Volume Title:Journal of Metamorphic Geology
Source:Journal of Metamorphic Geology, 15(3), p.311-322. Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263-4929
Publication Date:1997
Note:In English. 36 refs.; illus., incl. 1 table
Summary:Annealing experiments on agate, quartz schist and metachert at 800-1000°C, confining P of 400 and 800 MPa, and annealing times of 6.0 × 10-3.6 × 105s revealed normal grain growth of quartz in the agate with grain-size increasing with time, but with rate of grain growth decreasing with increasing grain size. The boundaries of agate with quartz schist and metachert migrated into the agate at the expense of fine-grained quartz in the agate. The driving force for the migration appears to be the reduction of surface energy associated with removal of fine-grained quartz in the agate. Assuming the activation energy as Qm = 11 kcal/mol, a general expression for the relationship between velocity of boundary migration (V) and driving force (P) is: V = 2.9 × 107 (P/3Γ)9 exp (-Qm/RT) where Γ is the specific surface energy of quartz, R is the gas constant and T the absolute temperature. The velocity is relatively fast at high T on a geological time-scale. The expression assists a quantitative understanding of the microstructural development of quartz at metamorphic conditions. [P.J.T.]
Subjects:Agate; Annealing; Crystal growth; Experimental studies; Foliation; Framework silicates; Grain boundaries; Grain size; High pressure; High temperature; Metachert; Metamorphic belts; Metamorphic rocks; Metamorphism; Metasedimentary rocks; Migration; Mineral assemblages; P-T conditions; Paleozoic; Petrofabrics; Physical models; Pressure; Quartz; Schists; Silica minerals; Silicates; Spatial distribution; Statistical analysis; Temperature; Aichi Japan; Asia; Far East; Honshu; Japan; Ryoke Belt; Sambagawa Belt; Wakayama Japan; Yomura River
Coordinates:N343500 N352500 E1375000 E1364000
Abstract Numbers:97M/3810
Record ID:1997038755
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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