What book would use such a phrase?
Of course, when garnet is missing other assemblages such as
hypersthene-cordierite replace it.
I still think that facies are significant to avoid making mistakes.
For instance, the thermodynamic properties of cordierite still are not
>Eric Essene wrote:
>"There is no such thing as "shallow contact metamorphic facies", as
>facies simply delineate a portion of P-T space, not the process by which
>I did not make this up, nor approve of it (in fact, I don't like it); I
>was just citing terms from petrology textbooks.
>"There are hornblende hornfels facies and pyroxene hornfels facies rocks
>that usually but not always formed during contact metamorphism. They could
>be defined by the absence of ferromagnesian garnet and by assemblages and
>composition fields that have been lucidly described by Pattison, for
>Absence of almandine is a valid point, but defining a facies by the
>absence of a mineral is bit odd. Apart from that, spessartine-rich
>almandine may still be stable, and even a thin section won't reveal the
>garnet composition unless it is put under the microprobe. However, once
>the sample is fully analysed and P-T is determined, the facies aspect
>becomes somewhat obsolete.
>Bruce Bathurst wrote:
>"Facies, as opposed to most isograds, are environmentally sensitive but
>independent of composition. They are identified in the field, using a
>lens, from an association of rocks containing typical assemblages, or the
>occasional single rock containing a critical assemblage."
>This underlines the practical use of facies as I understand it. I wouldn't
>restrict this entirely to the field though, and even experienced
>petrographers may not be able to identify every critical mineral in the
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