How Cool Would It Be To See A Volcanic Field in Montana?
Nestled beautifully between Great Falls and Helena is the Adel Mountains Volcanic Field, part of which is what we all call Wolf Creek Canyon.
While the Adel Mountains cover more than just Wolf Creek Canyon, it's the easiest way to see this spectacle while you travel through Montana.
Geologists have been studying the area for over a hundred years due to it's structure. It's home to shonkinite, an uncommon intrusive igneous rock mostly found in Montana, Ontario and Timor.
What is the Adel Mountains Volcanic Field?
The Adel Mountains Volcanic Field (also known as the Adel Mountains, Adel Volcanics, and Adel Mountain Volcanics) is an ancient volcanic field of heavily eroded 75-million-year-old igneous rocks about 40 miles long and 20 miles wide (800 square miles, or 2,071 square kilometers) in west-central Montana about 30 miles southwest of the city of Great Falls.
How did the Adel Mountains Volcanic Field Form?
Scientists have studied the area trying to date it many times. The most recent attempt puts it at about 75 million years old.
The Adel volcanics are part of the Laramide oroegny a period of mountain building in western North America which began about 80 million years ago and ended about 35 million years ago.
Magma welled up from below for several million years, creating the Adel volcanics as well as the nearby Highwood Mountains and Judith Mountains. The crustal weakness associated with the Great Falls Tectonic Zone may have provided a route for the magma to reach the surface. Magma which never made it to the surface nonetheless created the many dikes, sills, plugs, and laccoliths which can be seen in the Adel volcanic field.
What is the Great Falls Tectonic Zone?
When I saw that in the above description from Wikipedia, I had to look further. Just to see if it was related to active volcano and/or earthquake activity.
The zone is an area about 100 miles (150 km) wide extending from the southwestern Idaho-Montana border across Montana to the northwestern Montana-Saskatchewan-North Dakota border. It is named for the Great Falls of the Missouri River