The Exposed Volcanic Necks in this image are all related in space and time. Once deeply buried volcanic conduits to the surface. Each of the 4 peaks stands eroded at the surface. These pipes carried magma to the surface as lava/ash in four volcanos popping off at the surface . The rock we see here froze solid in that neck and cooled. We know this was deep as the column of rock in the Devils Tower cooled very slowly allowing the columns of rock the National Monument is famous for. Being our nations first national Monument is the moniker that Devil’s Tower and surround area carry. Wyoming and all that
Being 40 miles away from the tow and the buttes somewhat closer, this becomes a terribly long shot to actually be able to resolve the columns on the tower. There is SOME columnar jointing in the Missouri Buttes. Emplaced closely in time and space does not say they were coterminous in their eruptions. . We don’t know their exact schedule.
Phenolitic Porphyry is the name of the rock. It cooled into big 6 foot in diameter crystals up the length of the tower. I used one of several possibilities all related to volcanic activity to describe the tower as volcanic necks. There are multiple configurations and possible variations in this discussion I won’t get into here but feel free to google devils tower origin to discover more.
Location: The Pass at Rockypoint Wyoming, Trail Creek Road, NE Campbell Country
Here I have posted a very well developed “Belt of Venus” . NE Wyoming version. Lots of Ice in the air…..Backshow from the sun that just went down over my shoulder.
This is the view from the Pass at RockyPoint Wyoming showing the 4 volcanic necks. The debris from them being eroded (sediments) are draping off them making an apron of debris to the relatively hard peaks. The Devil’s Tower (left) is the best known volcanic neck in this complex
. The other three peaks were emplace around the same time as the towers rocks were cooling in the deeply buried neck of an ancient volcano.
“Belt of Venus” NE Wyoming
The Missouri Buttes AKA the Three sisters are in fact 4 buttes. Hard to see all 4 unless your on the top of Devils Tower though or in a plane. Two of the buttes rise slightly lower topographically than the Tower, while the remaining two are actually higher. Devil’s Tower was formed from the same type of rock type as the Missouri Buttes. Rocks there are classified as “phonolite porphyry” by geologists.
There is some agreement among geologist (rare thing lol) that these volcanic necks were from the same intrusion of magma. That event created the hard magmatic origin rocks that obviously later resisted erosion better than the surrounding sediments. Thus they stick out of the surrounding landscape that washed away.
Geologists think magmatic injection, lead to these erosional remnants (mountains). All these peaks rocks were formed during closely related volcanic timelines it appears. Although some columnar jointing is evident in the Little Missouri Buttes, they lack the distinctive appearance and magnificent grandeur of Devils Tower which cooled over a longer period of time allow the giant columnar crystals of Dark Porphyry. These eroded exposed volcanic necks dominate the landscape with their presence here in the NorthEastern Corner of the state. This is almost entirely in Crook County but I’m standing in Campbell County Wyoming.