| Text Description: |
Poorly exposed pumice bed at Site 9. Sample is approximately 6-8” in diameter. Fine-grained, hypocrystalline, porphyritic with a matrix of colorless glass, plagioclase, opaque and apatite?. Plagioclase phenocrysts (An27 - An55) are up to 1.4 mm and have strong oscillatory zoning and other complex zoning; some grains have resorption embayments. Orthopyroxene phenocrysts are up to 1.1 mm and have brown altered rims, and/or opaque inclusions. Clinopyroxene phenocrysts are up to 0.5 mm. Opaque phenocrysts are up to 0.3 mm. Amphibole phenocrysts are up to 0.1 mm. Dehydrated amphibole? (clinopyroxene, orthopyroxene, plagioclase) is represented by a clump of small crystals. 54.6% matrix, 17.1% plagioclase, 2.3% orthopyroxene, 0.5% opaque, 25.5% vesicles. |