Pelagic Sediments

Marine Science - Sediments

Why is the Atlantic Ocean floor sediment thicker than the Pacific ocean floor?

1. The Atlantic Ocean is fed by greater number of rivers laden with sediment than the Pacific. The Atlantic is smaller in size, thus, it gets more sediment for its size than Pacific.

2. Many ocean trenches trap sediment in the Pacific Ocean from moving toward basin centre.

3. Thickness of pelagic sediments also vary with location, being thickest on the abyssal plains and thinnest on ocean ridges.

What is a turbidity current?

A turbidity current is a dilute mixture of sediment and water that periodically rushes down the continental slope.

What propels a turbidity current?

Gravity propels turbidity currents. The water suspends the sediment particles, making the mixture denser than the surrounding seawater.

What role do turbidity currents play in forming submarine canyons?

Their erosive force helps cut and deepen submarine canyons.

Where can turbidity currents travel, and what happens to them eventually?

They can travel down the continental rise and continue onto an adjacent abyssal plain before eventually coming to rest.

What are turbidities, and how are they formed?

Turbidities are graded layers of terrigenous sand interbedded with finer pelagic sediments on the deep-sea floor. Each layer forms from one turbidity-current event, with coarse sediment deposited at the bottom and progressively finer sediment deposited above.