Geologic setting

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Another low-angle sunlight masterpiece from space. Among other things, this is a photograph of the Colorado River. From the delta on the gulf, it goes left, then up ti Yuma in about the middle of the frame. Straight up from there is the raggedy edge of the Grand Canyon where it crosses the Kiabab Plateau and the river is lost in cloud and poor resolution. 

The dozen cones of San Quintin, another alkali-basalt volcanic field are down at the bottom, at the end of the hook-shaped bay shoreline. The little island, 5 km offshore, is a volcano, as is the end of the n-s spit.

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Pinacate and the Basin & Range.

C - Cholla Bay Granodiorite
G - Grand Canyon
GB - Great Basin
LA - Los Angeles City
M - Lake Mead
P - San Pedro Martir in Baja California
R - Colorado (Grand) River
S - San Andreas Fault
SN - Sierra Nevada
Y - Yuma

The light-blue band west of Salton Sea is approximately the plate boundary which connects to the San Andreas Fault. The purple line east of Salton Sea is the extension of the San Andreas which becomes the western boundary of bedrock outcrops in the sediment wedge south of Salton. International border is yellow line.