We invite your contribution to Symposium 22.5 Anatexis, one of 6
sessions in Theme 22 “Metamorphic Rocks and Processes”
(http://www.34igc.org/scientific-themes-symposia.php#theme-22-metamorphic-rocks-and-processes)
at the forthcoming IGC in Brisbane, early in August 2012 (see:
http://www.34igc.org/).
Keynote speakers are: Edward SAWYER (Canada), Fawna KORHONEN
(Australia), Gary STEVENS (South Africa) and Fernando BEA (Spain).
A description of the session is given below. The abstract deadline is
Friday 17 February 2012 (see: http://www.34igc.org/submit-abstracts.php).
We hope to see you in Brisbane in August.
Mike Brown (on behalf of the session convenors)
Anatexis
Michael Brown, University of Maryland, USA,
[log in to unmask]<mailto:[log in to unmask]> Bernardo Cesare, Universita' di
Padova, Italy, [log in to unmask]<mailto:[log in to unmask]>
Geoff Clarke, The University of Sydney, Australia,
[log in to unmask]<mailto:[log in to unmask]>
Gary Stevens, Stellenbosch University, South Africa,
[log in to unmask]<mailto:[log in to unmask]>
Anatexis is the most important process affecting the Earth's crust. It
occurs in the deep crust of arcs along convergent plate margins, and in
collisional mountain belts and orogenic plateaus, as recorded by
extensive migmatite and granulite terrains now exposed at Earth's
surface. As melt develops on the edges and faces of mineral grains it
affects rock strength and strain rate, which has important consequences
for the way the crust deforms and the style of orogenic belts. During
the Phanerozoic anatexis was potentially an important component in the
exhumation of rocks from ultrahigh pressure mantle conditions after
continental subduction, and during the Archean partial melting of
subducted or sagducted basaltic crust gave rise to granite types that
are rare on Earth today. The nature of the source and the conditions
under which melting occurs determine the character of the resulting
melts, as exemplified by secular change in granite type and the
relationship between tectonic setting and granite chemistry. The
extraction and ascent of melt led to the redistribution of elements in
the crust, and was responsible for the large-scale compositional and
density structure that stabilized the continents over geological time.
This session deals with all issues relating to anatexis, including the
source of the heat responsible for widespread melting and theinformation
that can be retrieved from mineral assemblages and microstructures in
partially melted rocks. It will explore the mechanisms of melt transfer
and the large-scale geodynamic consequences of partial melting in
diverse settings. Contributions that use or integrate data from field
observations, petrology, melting experiments, geochemistry, geophysics,
and thermodynamic, numerical and analogue modelling are welcome.
__________________________________________________________
Michael Brown, Professor of Geology
Department of Geology
Geology Building (#237)
University of Maryland
College Park
MD 20742-4211
USA
[log in to unmask]
http: www.geol.umd.edu
Dept. office: 301 405 4082; Direct line: 301 405 4080
Direct fax: 301 314 7970; Dept. fax: 301 314 9661
LABORATORY FOR CRUSTAL PETROLOGY (Information at:
http: www.geol.umd.edu/pages/faculty/BROWN/LCP/lcp.htm)
__________________________________________________________
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