The Distribution of Hydrous Impurities in Quartz : The Role of Twinning

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2018-04Author
Ihinger, Phillip D.
Fitzpatrick, William A.
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Show full item recordAbstract
Quartz crystals have been studied since ancient times by scientists and natural philosophers
attempting to unlock the mysteries behind their aesthetic appearance and cryptic morphological
properties. Previous studies have begun to identify controls on the abundance and distribution of
hydrous impurities (AlOH, LiOH and HOH) within gemmy hydrothermal quartz crystals
collected from veins in the Swiss Alps. These studies used high-resolution (200 μm2 scans)
traverses across sawn and polished crystal wafers that reveal trends in impurity concentrations
both parallel and perpendicular to the c-crystallographic axis, as well as within optical ‘sector
zones’ that correspond to growth on distinct rhombohedral and prism faces. Subtle differences in
crystal structure between growth faces appear to influence the respective growth rates of the
faces, resulting in a positive correlation of impurity concentration with growth rate. The
differences in crystal structure also likely influence rate of impurity mobility, which results in
the observed abundance profiles within the sector zones. We explore the effect of twinning on
the abundance of hydrous impurities within single crystals. We aim to develop a comprehensive
understanding of impurity behavior within quartz crystals in order to use their abundances to
elucidate thermal and compositional histories of fluids within metamorphic hydrothermal systems.
Subject
Posters
Quartz crystals
Geology
Crystals
Twinning
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http://digital.library.wisc.edu/1793/80078Description
Color poster with text, images, graphs, and diagrams.