Station 11 Joints

Joints 

One of the more obvious features of the Almo pluton. Joints result from stresses produced by thermal expansion/contraction related to a decrease in overburden pressure, and plate tectonics. Perhaps the most common joint-producing stress is thermal contraction thatoccurs as the pluton cools deep underground. Granite contracts as it cools, and the joints are produced as these stresses pull theminerals apart. 

Scientific explanations aside, the artistic patterns of these joints within the Almo pluton make it worthy of second look. Notice that the joints range from a hairline to more than two inches wide. Each year the joints widen until the outcrop becomes little more than cobbles and grus.