18 August 2012
Evelyn put up a cat photo on Geokittehs earlier today, and it reminded me of anatexis, the process of partial melting. Anatexis is my favorite way to produce a migmatite.
In this model, the light-colored (felsic) ginger cat is derived from the partial melting of another cat, partly dark (mafic) and partly felsic (ginger). Where the low-melting-temperature minerals have been extracted, the source cat is much darker. Fresh injections of felsic magma at regular intervals produce schlieren in the new magma body next door to the source rock.
Whaddya think? Got a better idea? Let Evelyn know.