Station 6 Intrusive Contact

Intrusive Contact of the Almo Pluton and Green Creek Complex 

The Almo pluton originated as an intrusive body of magma and has a convoluted and sometimes obscure contact with the surrounding Green Creek Complex. Here, one can see the contact clearly. As the Almo pluton intruded, it wedged its way into weaknesses formed by bedding planes, joints and metamorphic layering. Huge slabs of the Green Creek Complex detached completely or swung down into the magma like trap doors. 

Veins are thin dikes formed by igneous intrusions into cracks. Some of the veins are made of pure quartz while others are composed of a mixture of fine-grained quartz and feldspar called aplite (seen here).