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Figure F28. Photomicrographs in cross-polarized light taken with a blue filter at 5x magnification. Cpx = clinopyroxene, Pl = plagioclase. A. Cryptocrystalline groundmass observed at the top of Subunit 4B (Sample 205-1253A-13R-1, 35-37 cm). B, D. Progressive increase of the groundmass grain size in Core 205-1253A-25R from cryptocrystalline basalt (Sample 205-1253A-25R-1, 33-35 cm) in B through microcrystalline groundmass (Sample 205-1253A-25R-2, 101-103 cm) in D. C. Sample 205-1253A-25R-2, 3-5 cm.
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