| Text Description: |
Approximately 20' thick flow on the east side of Jaeger Mesa. Fine grained, holocrystalline, porphyritic with a matrix of opaque, plagioclase, microlites, orthopyroxene?, clinopyroxene and cryptocrystalline material. Plagioclase phenocrysts (An42-An61) are up to 3.0 mm, frequently have sieve textured cores and overgrowth rims and occasionally have resorption embayment; both normal and oscillatory zoning are present. Olivine phenocrysts are up to 1.1 and have opaque coronas. Clinopyroxene phenocrysts are up to 4.25 mm. Orthopyroxene phenocrysts are up to 1.3 mm. Mode: 70.8% matrix, 21.7% plagioclase, 4.0% olivine, 1.6% clinopyroxene, 1.9% orthopyroxene. |