Natural Resources

Metamorphic Rocks

Schist

A metamorphic rock having a strong planar structure called schistosity resulting from the parallel orientation of platy minerals, such as mica, chlorite and talc.

Schist Schist

A planar foliation or schistosity defined by biotite, quartz and feldspar is represented in the photograph on the left. The eye-shaped (augen) red garnet crystals are called porphyroblasts. A widely-spaced, mineral banding, defined by light and dark bands, indicate that the rock also has a gneissic component (see Gneiss). This sample comes from the Port aux Basques area.

The photo on the right shows staurolite crystals, called porphyroblasts, in a mica schist. Note the small quartz vein in the upper right-hand corner. This sample comes from the Bay d'Espoir area.

Amphibolite

A metamorphic rock consisting of mostly amphibole and plagioclase feldspar.

Amphibolite

A folded mafic dyke, in this photo, has been metamorphosed to mostly amphibole (hornblende) and plagioclase; it cuts across marble derived from limestone. (Rigolet, Labrador).

Gneiss

A coarse-grained metamorphic rock with a banding (gneissosity) produced by alternating layers of light and dark materials.

Gneiss

The gneissic banding produced by alternating layers of light and dark minerals comes from the Postville area of Labrador. The banding is not sedimentary, but is due to metamorphism.

Migmatite

A mixture of old metamorphic (dark) and new igneous granitic (light) material caused by the interlacing of thin veins and stringers of granitic material with metamorphic rocks.

Migmatite

Dark, biotite-rich metamorphic rocks in a medium-grained, light coloured granitic rock containing quartz and feldspar. This photo is from the Spruce Pond area, on the Burgeo Road.

 
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