| Text Description: |
Float boulders in Finger Creek Bed from the upper part of Dome C. Fine grained, vesicular, holocrystalline, porphyritic to glomeroporphyritic with a matrix of cryptocrystalline material, feldspar, orthopyroxene, opaque and minor alteration. Plagioclase phenocrysts (An33 - An57) are up to 0.94 mm and commonly are oscillatory zoned; some have resorption embayments and cores tend to have large holes present. Amphibole phenocrysts are up to 1.7 mm, most are dehydrated to fine opaque, with only a few amphibole cores preserved. Orthopyroxene phenocrysts are up to 0.6 mm and some have opaque inclusions. Opaque phenocrysts are up to 0.25 mm. |