At 10:07 AM 01/11/2002 -0500, Hannah Nekvasil wrote:
>Folks,
>I am planning a series of experiments that involve fluid-mediated trace
>element mobility during dehydration and dehydration/melting of amphibolite,
>focusing in particular on those element important to the common radiogenic
>isotopic systems. ...
I would suggest focus on dehydration-melting - by far the more important
process. Rocks that contain all the reactants and products (except liquid)
of natural dehydration-melting reactions are not hard to find. But because
the minerals change composition with increasing P along the
dehydration-melting curve, I would recommend doing melting experiments only
at your best estimate of the equilibrium P for a particular rock sample.
If you can work at 8-10 kbar, you might be interested in good-looking
Grenville granulite with the assemblage
Grt+oPx+cPx+Hbl+Plg+Kfs+Qtz+Ilm+Mt+metamict allanite. At specified
plagioclase composition, the dehydration-melting reaction would be
univariant in the system Na2O-K2O-CaO-MgO-FeO-Fe2O3-TiO2-Al2O3-SiO2-H2O.
Cheers, Dugald
Dugald M Carmichael Phone/V-mail: 613-533-6182
Dept of Geological Sciences and Geological Engineering
Queen's University FAX: 613-533-6592
Kingston ON K7L3N6 E-mail: [log in to unmask]
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