Browse Items (1651 total)

Deep brown oxidation with yellow (limonite?) area

Garnet Gneiss from the Kinsman Quartz Monzonite. Thin section contains large alkali feldspar porphyroblasts, plagioclase, biotite, muscovite, garnet, and quartz. Hand sample is coarse grained and cataclastic, and contains plagioclase, bitote,…

contains melt-like aggregates

Schist with sparse garnet. This schist is darker and graphitic. It also contains biotite, chlorite, muscovite, feldspar, and quartz.

The thin section shows several large biotite grains with an included garnet, small quartz grains, muscovite, and…

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Leucocratic, orthorhombic pryoxenes abundant

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

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

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

Rock may have undergone some alteration

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

contains clots of black spheroids

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…

Dark gabbro dike separating ijolite and uncompahgrite

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…

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Hand Sample: Phaneritic rhyolite with fine-grained phenocrysts of quarts, feldspar and hornblende in a brownish-red groundmass. Weathers to orange-brown.

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