Browse Items (1651 total)

Altered Basalt-greenstone

Hyaloclastite of basalt with superimposed metamorphism in pumpellyite-prehnite facies.

Hand Sample: On cut face, aphanitic, gray basalt with light colored phaneritic crystals (~0.1 cm in size). Subparallel fractures noted across sample. Exterior of sample has been heavily weathered, resulting in the red and orange discoloration.

Rock Sample:
The sample is brown to white to green in color. It is porphyritic and has foliations that fan out. There are also wide fractures (≤1mm in length). There is a brownish orange coating which is evidence of chemical weathering. There…

Rock Sample:
The overall matrix is a dark green blue but there are many different colored clasts that give it a mixture of colors. The color of the clasts range from brick red, pink, white, and green (non-reactant to acid). The texture of the rock…

with relict pyroxene and plagioclase

Satalitic intrusion

possibly volcanic

1:62500
unlaminated copies are somewhat faded

1:62500
unlaminated copies are somewhat faded

1:250000

1:250000

Dark, banded

Macroscopic: Grey massive biotite, muscovite granite. Overall white and grey color. Only slightly weathered.  Microscopic: Abundant in alkali feldspar, plagoclase, quartz and mica. Thin section pictures in XPL unless otherwise noted in the title of…

Biotite is variable in amount, but it is always evenly distributed