Figure F16. Photomicrographs of plagioclase. A. Relict plagioclase phenocryst within a granoblastic basalt showing relatively high anorthite (An) core surrounded by a lower An, reversely zoned rim (determined by Michel-Levy method) (Sample 335-1256D-Run15-EXJB; Thin Section 35) (cross-polarized light). The contact between the relict core and rim is marked by small granular pyroxene and Fe-Ti oxide crystals. B. Reverse zoning in plagioclase of the granoblastic matrix of the same thin section (cross-polarized light).
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