Monterey Canyon, or Monterey Submarine Canyon, is a submarine canyon in Monterey Bay, California. It is the subject of ongoing study by the scientists at the Monterey Bay Aquarium Research Institute, the Moss Landing Marine Laboratories, and other oceanographic institutions.
Monterey Canyon begins at Moss Landing, California, the middle of the Monterey Bay, and extends 95 mi (153 km) into the Pacific Ocean where it terminates at the Monterey Canyon submarine fan, reaching depths of up to 3,600 m (11,800 ft) below surface level at its deepest. Though the canyon's bottom is about 2 miles below the surface, the actual canyon itself is only about 1 mile deep, making it of comparable depth to the Grand Canyon. It is a part of the greater Monterey Bay Canyon System, which consists of Monterey, Soquel and Carmel Canyons. The canyon's depth and nutrient availability (due to the regular influx of nutrient-rich sediment) provide a habitat suitable for many marine life forms.
The Soquel Canyon State Marine Conservation Area protects a side-branch of the Monterey Submarine Canyon. Like an underwater park, this marine protected area helps conserve ocean wildlife and marine ecosystems.
One dominant theory holds that the canyon is a remnant of an ancient outlet of the Colorado River which existed before the Gulf of California opened up about 7.9 million years ago. Others believe it may represent the remnant outlet of a river draining the Central Valley, perhaps by way of the Los Angeles Basin. The canyon has moved north to its current location by the action of the San Andreas Fault and would have been approximately where Santa Barbara is located when both the San Andreas Fault and the Gulf of California came into being. Similar undersea canyons exist at the mouths of other large rivers around the world today, for instance, the Hudson River Canyon. As no major river lies at the head of Monterey Canyon today, it is surmised that it may have come into being when such a river did so in the past. The clues to its ancient origins lie somewhere at the base of the canyon in a huge sedimentary bed called the Monterey Fan. This fan appears to be far too massive to have accumulated from modern coastal streams. Research including core sampling is ongoing. Thus far, only "recent" sedimentary cores have been obtained. The oldest cores lie deeply buried, and remain to be probed.
- Allen, Robert Lloyd, Jr. (March 1982). The Impact of Tectonic Activity in the Development of Monterey Submarine Canyon. Naval Postgraduate School Monterey. Retrieved 2009-10-16.
- "Monterey Canyon System". Monterey Bay Aquarium Research Institute. 6 February 2009. Retrieved 2009-10-16.