User:Jenniferlight17/Continental rise

= Assignment 3-Draft Your Contributions[edit] =


 * 1) Lead Section

The continental rise is a low-relief zone of accumulated sediments that lies between the continental slope and the abyssal plain.

2. Article

The continental rise is a major part of the continental margin, covering around 10% of the ocean floor. This geologic structure results from the deposition of sediments due to multiple processes. The main process that forms the continental rise is mass wasting, the gravity-driven downhill motion of sand and other sediments. Mass wasting can occur gradually or over large time periods, with sediments accumulating discontinuously, or in large, sudden events. Large mass wasting occurences are often triggered by sudden events such as earthquakes or the oversteepening of the continental slope. More gradual accumulation of sediments at the continental rise occurs when hemipelagic sediments suspended in the ocean slowly settle to the ocean basin.

Because the continental rise lies below the continental slope and is formed from sediment deposition, it has a very gentle slope, usually ranging from 1:50 to 1:500. As the continental rise extends seaward, the layers of sediment thin and the rise merges with the abyssal plain, typically forming a slope of around 1:1000. The abyssal plain lies on top of basaltic oceanic crust and spans the majority of the seafloor.

Alluvial or sedimentary fans are shallow cone-shaped reliefs at the base of the continental slope that merge together, forming the continental rise. Erosional submarine canyons slope downward and lead to alluvial fan valleys with increasing depth. It is in this zone that sediment is depositied, forming the continental rise. Alluvial fans such as the Bengal Fan, which stretches 3000 km, make up one of the largest sedimentary structures in the world. Many alluvial fans also contain critical oil and natural gas reservoirs, making them key points for the collection of seismic data.