Sandstone Pipe In Sandstone
Sandstone pipes are vertical cylindrical features that are commonly preserved in the St. Peter Sandstone in northern Arkansas. They are made up of the same sand as the surrounding rock. These features were observed in Ordovician-aged sandstone in Arkansas by geologists as early as 1916. Research by other scientists showed that these pipes formed in sand that was slightly deformed by a column of water rising through it from a lower horizon and feeding a spring at the surface. This sand then lithified into the rock we see today which includes the sandstone pipe. A modern-day example of sandstone columns forming in springs is present in the Dismal River, in the Nebraska Sand Hills. At this location, boiling (motion from water pressure, not temperature) sand springs have developed, fed by groundwater moving upward along cylindrical conduits. In the picture above, the sandstone surrounding the pipe has eroded away leaving the sandstone pipe standing in relief.