Nojoqui (pronounced NAH-ho-wee according to a park employee) fall is located at the transition from shale to sandstone in the Jalama Formation. The canyon walls from the parking lot to the falls are composed of the shale. It is a relatively weak, easily eroded rock as can be seen by the many small rock slides. The sandstone of the Jalama Formation is much more resistant to erosion, so it forms the high steep cliff of the falls.
The falls form here because there is a contact from hard sandstone to the weaker shale at this point. Over time, the shale eroded down faster than the sandstone, leaving the high cliff for the water to cascade over.
Typically, water flowing over rocks will erode them slowly moving the fall upstream. However, in this case, the water is actually depositing material on the face of the falls, moving the falls downstream. The sandstone in the Jalama Formation is cemented together with calcium and/or magnesium carbonate. The water in the stream dissolves the calcium and/or magnesium carbonate in the sandstone and then as it cascades down the falls deposits some of it on the face of the falls as a little of the water evaporates. This is the same process that creates stalactites in caves.
At the base of the falls is an educational panel that gives a bit more information on the formation of the Jalama Formation and some graphics that will be useful answering the logging requirements.
Have a look at the side of the falls to see how the falls have been building up. A look underneath will give you a better look at the new rock that is being formed, but be careful if you don’t want to get wet.
Send me a note with :
(Advanced question not on the panel and not required for log)
- The text "GCZ5TQ Nojoqui Falls - Advancing Falls" (or something similar) on the first line
- The number of people in your group.
- the age of the Jalama Formation and the environment in which it was deposited.
- the name of the rock that is being deposited on the face of the falls.
The dissolving of calcium and/or magnesium carbonate is what type of weathering?
The above information was compiled from the following sources:
- Santa Barbara County Parks Informational Pannel
- Geologic Map of the Solvang Quadrangle, Thomas W. Diblee, Jr., 1981