|The Sutter (or Marysville) Buttes rise with astonishing suddenness out of the Sacramento Valley. They are the only significant outcrops in the entire valley.|
Buttes are not just unique, they are remarkably steep. They consist of
rhyolites and andesites about 1.5 million years old.
Given that some of the large Cascade Range stratovolcanoes are over a million years old, it is clear these were never in the same class, in size or longevity. They were probably more like the Mono Craters, a cluster of small and relatively short-lived vents.
of the outcrops themselves are on private land and not accessible without
permission. However, road cuts and boulders along the public roads give a
fairly clear picture of the geology.|
Recently, large tracts of private land were acquired and hopefully this area will become a State park.
|"In commemoration of Major General John C. Fremont, United States Army and his expedition encamped in the Sutter Buttes in this vicinity May 30, 1846 to June 8, 1846 while on a march from Klamath Lake to Sonoma where he represented the United States government during the Bear Flag Uprising which resulted in the acquisition of California from Mexico."|
For those not familiar with California history, the Bear Flag Uprising was a coup by American settlers during the Mexican War that proclaimed California a (briefly) independent republic. The flag became the present California state flag. The bear on the flag is a grizzly bear, which ironically became extinct in California shortly after 1900.
|Stone walls were once numerous here, a startling sight since stone walls are not common in California.|
The panorama above shows the resistant volcanic necks at right and the outward-dipping apron of lahars, flows, and pyroclastic debris at left.
|Rock pile of volcanic boulders.|
The panorama above shows the resistant volcanic necks in the distance flanked on both sides by their outward-dipping apron of lahars, flows, and pyroclastic debris.
|Below: views of the flat Sacramento River valley looking west.|
|A number of properties in this area make use of the abundant volcanic boulders for stone walls.|
windows of Cretaceous sandstone occur in the Buttes (above)
Left: doming of the underlying sedimentary units by the volcanic uplift created natural gas traps and natural gas wells are located around the buttes. One can be seen at lower left of the photo.
|Tertiary gravels occur in places on top of the Cretaceous.|
|The gravel here is clearly not derived from the local lithology. The sandy unit underlying the gravel (below) may be Tertiary or may be Cretaceous in part.|
|A lahar on the southwestern flank of the buttes|
|Left and below: road cuts in the volcaniclastic apron of the buttes. Road cuts like these are best seen along the western side of the buttes.|
|Left and below: roadside boulders allow frequent opportunities to sample the volcanic rocks, which seem to be uniformly coarse porphyritic rhyolites.|
Created 7 April 2003, Last Update 01 July 2012
Not an official UW Green Bay site