The Farallon Basin is a submarine depression

Depression (geology)

A depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms.Structural or tectonic related:...

 located on the seabed at the southern end of the Gulf of California

Gulf of California

The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...

. The basin results from the activity of one of the several spreading centers in the Gulf. The basin is linked to the Atl Fault

Atl Fault

The Atl Fault is a right lateral-moving transform fault located on the seafloor of the southern Gulf of California. It links the Farallon Basin to the north with the Pescadero Basin to the south. All these features are part of the Gulf of California Rift Zone, the northern extension of the East...

 to the south, and the Farallon Fault

Farallon Fault

The Farallon Fault is a right lateral-moving transform fault located on the seafloor of the southern Gulf of California. It links the Carmen Basin to the north with the Farallon Basin to the south. All these features are part of the Gulf of California Rift Zone, the northern extension of the East...

 in the north.

The Farallon Basin has a spreading axis at its center, so the seafloor here is oceanic crust

Oceanic crust

Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...

, transitioning into thin, rifted continental crust at the basin's edges. Spreading centers in the Gulf, like this one in Farallon, are different from more well known spreading axes like the Mid-Atlantic Ridge

Mid-Atlantic Ridge

The Mid-Atlantic Ridge is a mid-ocean ridge, a divergent tectonic plate boundary located along the floor of the Atlantic Ocean, and part of the longest mountain range in the world. It separates the Eurasian Plate and North American Plate in the North Atlantic, and the African Plate from the South...

 and East Pacific Rise

East Pacific Rise

The East Pacific Rise is a mid-oceanic ridge, a divergent tectonic plate boundary located along the floor of the Pacific Ocean. It separates the Pacific Plate to the west from the North American Plate, the Rivera Plate, the Cocos Plate, the Nazca Plate, and the Antarctic Plate...

, since they form as deep rift valleys rather than bathymetric highs.

One familiar source of terrigenous input to the Gulf is the Colorado River

Colorado River

The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

, which empties into the northern Gulf (though no longer consistently, as a result of overuse for irrigation). Further south, especially in the eastern Gulf, the Sierra Madre Occidental

Sierra Madre Occidental

The Sierra Madre Occidental is a mountain range in western Mexico.-Setting:The range runs north to south, from just south of the Sonora–Arizona border southeast through eastern Sonora, western Chihuahua, Sinaloa, Durango, Zacatecas, Nayarit, Jalisco, Aguascalientes to Guanajuato, where it joins...

are a more important source of sediment.