Browse Items (10 total)

  • Title is exactly "Gabbro"

PH-9 Hand Sample.
Coarse gabbro, extracted from the southern dike of two east-west dikes N of Deldardo Creek.

Hand Sample:

Evenly distributed dark, light, and white colored coarse-grained (1 mm) crystals. Obvious traces of oxidation from some metallic mineral…

PH-18 Hand Sample - Horizontal.
Dark gabbro dike separating ijolite and uncompahgrite
Gabbro with hydrothermal "oceanic" processes and prehnite-pumpellyite metamorphic overprint.
Plagioclase, clinopyroxene, olivine, ilmenite. metamorphic paragenesis: albite, sericite, chlorite, hematite, sphene, carbonates. Well-preserved relics of…

contains clots of black spheroids

Fedlspar is cream-pink colored and much has been altered to sericite/epidote

Rock may have undergone some alteration

Amphibole, epidote, chlorite, quartz, calcite, and clinozosite present are thought to be alteration products

Rock appears to be hydrothermally altered, sample is taken from a sill and is source of basaltic tuffs in area

Rock has been subjected to alteration and shear forces, the garnet present is probably an alteration product

Leucocratic, orthorhombic pryoxenes abundant
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