"Regional metamorphism" need not be deep seated (e.g. the
andalusite-Kfeldspar gneisses regionally exposed in the Lachlan Fold Belt),
and "contact metamorphism" need not produce high-level hornfels (e.g.
staurolite/kyanite schist spatially related to intrusive contacts in Ireland
and Vermont). Where regional and contact metamorphism are associated, their
separate effects can often be distinguished. In my experience contact
metamorphism is normally younger and shallower than associated regional
metamorphism (e.g. in the Swiss/Italian Alps), but there are exceptions
(e.g. in the Slave craton near Yellowknife, where the regional metamorphism
is younger and shallower than associated contact metamorphism). Where is
there a well documented example of a strictly coeval "hybrid between contact
and regional metamorphism"?
Dugald M. Carmichael Phone/V-mail: 613-533-6182
Geological Sciences, Queen's University FAX: 613-533-6592
Kingston ON K7L3N6 E-mail: [log in to unmask]
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