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Fall AGU Session: Crystal-scale records of magmatic processes
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From: Sylvie Demouchy <demou005@xxxxxxx>
Dear All,
We would like to draw your attention to the following special session at
this fall's AGU:
V15: Crystal-scale records of magmatic processes
Sponsor: Volcanology, Geochemistry and Petrology
Co-Sponsor: Mineral and Rock Physics, Study of the Earth's Deep
Interior, Tectonophysics.
Conveners:
Kari M. Cooper
University of California, Davis
Dept. of Geology
One Shields Avenue
Davis, CA USA 95616-8605
530-754-8826
<mailto:kmcooper@xxxxxxxxxxxxxxxxxxx%20>kmcooper@xxxxxxxxxxxxxxxxxxx
Sylvie Demouchy
University of Minnesota
Dept. Geology and Geophysics
Pillsbury Hall, room 108
310 Pillsbury Drive SE
Minneapolis, MN, USA 55455
612-626-0572
<mailto:demou005@xxxxxxx>demou005@xxxxxxx
Description:
In order to understand the information about the composition and the
dynamics of the Earth's mantle that is provided by the chemistry of
magmas, it is necessary to deconvolve the geochemical signatures of
crustal transport and storage from those that reflect melt production,
migration and transport through the mantle. There is a growing
recognition that chemical variations in crystals in magmatic systems can
record many of these processes, which may be averaged (and therefore
obscured) in the chemistry of the silicate liquids. For example,
trace-element zoning in crystals can preserve information about the
changing chemical conditions within a magma system, while
geochronometers based on diffusion of major and trace elements within
crystals can provide information on the duration of crystal residence at
high temperatures, with resolution from several thousands of years for
magma storage to few hours for the ascent rate of kimberlites. Absolute
ages of crystals can be determined by in-situ dating of accessory phases
by U-Th or U-Pb dating, and average crystal ages can be determined
through U-series ages of bulk mineral separates. In this session, we
will explore the chemical and temporal records of magmatic processes
that are contained within crystals. We encourage contributions from a
wide range of fields including observational, experimental and
theoretical studies in geochemistry, petrology, and mineral physics
concerning the timescale of magmatic processes recorded by minerals (for
example, growth, resorption, or recrystallization of phenocrysts,
storage and recycling of crystals within magmatic systems, diffusion in
mantle-derived xenoliths). We especially encourage submissions that
combine multiple techniques applied to the same system.
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