Located in Northern California about 55 north of the state capital, Sacramento, lies a small volcanic formation often billed as “the world’s smallest mountain range.” Known as the Sutter Buttes, the formation spans a modest 10 miles across, making it a unique and compact formation amid the expansive flat surroundings of the northern part of California’s Central Valley.
James Dwight Dana, a geologist traveling with the United States Exploring Expedition in 1841 described Sutter Buttes as being “like an island in a vast prairie of millpond smoothness.”
The highest point in this compact and isolated range is South Butte, which reaches an elevation of approximately 2,117 feet (645 meters) above sea level.
What are the Sutter Buttes
The Sutter Buttes are a volcanic formation, estimated to have arisen from volcanic activity around 1.6 million years ago during the Pleistocene Epoch. Unlike extensive mountain ranges formed by tectonic plate interactions over vast timescales, the Sutter Buttes were formed by the eruption of a now-dormant volcano.
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This volcanic activity created a circular complex of peaks surrounded by the flat terrain of the valley floor. The interior of the buttes is known as the central core or the castellated core.
Surrounding the core is an apron of fragmental material created by occasional eruptions of the lava domes. This debris traveled from the core by two processes: volcanic gas-driven pyroclastic flows or by cooler, water-driven lahars (fast-moving volcanic mudflows composed of water, ash, rock, and other debris).
Between the apron and the core is a geomorphologic feature known as the “moat”, formed by the erosion of older sedimentary rocks beneath the volcanic layers. This moat is made up of layers shale, sandstone, and conglomerate that range in age from about 70 million years ago (late Cretaceous) to about 1.6 million years ago.
Surrounding the buttes is a patchwork of agricultural fields. Dominant crops include rice, sunflower, almond trees, and tomatoes.
An inland island
Most of the Sutter Buttes is privately owned, with land rights dating back 150 years. Limited public access to the mountain range is available via deeded 200 acres of land managed by the Sutter Buttes Regional Land Trust.
The Sutter Buttes represent a unique ecological enclave, often described as an “inland island” due to its isolation from other mountainous terrains but the formation has been historically under-researched, primarily due to the private ownership of the land.
References
Hausback, B. P., Muffler, L. P., & Clynne, M. A. (2011). Sutter Buttes-the lone volcano in California’s Great Valley (No. 2011-3024). US Geological Survey.
Olson, E. O., Shedd, J. D., & Engstrom, T. N. (2016). A field inventory and collections summary of herpetofauna from the Sutter Buttes, an “inland island” within California’s Great Central Valley. Western North American Naturalist, 76(3), 352-366.
