Feldspar terrestrial weathering

A surprise difference between the chondrule mesostases of Semarkona and Krymka was that while the luminescent chondrule mesostases in Krymka luminesce blue, in Semarkona, chondrule mesostases display yellow CL when the mesostasis is calcic in composition and blue CL when they are sodic (Figure 8) Calcic compositions differ from sodic compositions in that they crystallize more readily, and, in terrestrial weathering studies, react more readily with water than sodic feldspars. It is probable that the yellow CL may be signalling aqueous alteration or the presence of a metastable phase easily destroyed by metamorphism ... 

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