The Grand Canyon of the Atlantic
Agadir Canyon and its associated Basin are located in the North Atlantic Ocean off the northwest cost of Morocco. The earth’s crust in this vicinity is very stable, with minimal earthquakes. This has allowed the sediment, mostly washing down from the Atlas Mountains and surrounding areas, to become thicker than usually occurs. Over time, portions of the sediment layer collapse, creating an underwater avalanche. This avalanche results in a turbidity current, carrying the sediment out to the basin floor. The seabed in this vicinity contains a number of salt diapirs, bodies of rock salt that rise above the ocean floor because they are less dense than the surrounding rock. There are also a few seamounts, formed from extinct volcanoes. These features channel the sediment flow and have influenced the shape and extent of the Agadir Canyon. Due to the high volume of the turbidity flows through the Canyon, sediment has been carried a distance of almost 1,000 miles from the Morocco coast. At a half-mile deep, 280 miles long, and 20 miles wide, the Agadir Canyon has dimensions similar to that of the Grand Canyon of the Colorado. The difference is that the Grand Canyon attracts millions of visitors and has been explored and studied in detail, while the Agadir Canyon is almost unknown and has only recently been charted. Although comparisons are understandably imprecise, the Agadir Canyon may well be the world’s largest submarine canyon. It has taken millions of years of sedimentation and erosion to achieve its present condition. Recent research, though, reveals that about 60,000 years ago, a massive underwater landslide produced the largest known sediment flow, when up to 38 cubic miles of sediment moved through the canyon and out onto the Agadir Basin, covering an area roughly the size of Germany. The canyon consists not just of sediment – it is also home to a diverse ecosystem of coral, fish, and whales.