Author Question: Identify the CCD, and describe the distribution of calcareous oozes in the deep ocean. What will be ... (Read 71 times)

brutforce · **on:** Aug 22, 2018

Identify the CCD, and describe the distribution of calcareous oozes in the deep ocean. What will be an ideal response?

Question 2

Describe the movement of a turbidity current and the resulting sediment deposit. What will be an ideal response?

javimendoza7 · **Reply #1 on:** Aug 22, 2018

Answer to Question 1

The calcium carbonate compensation depth (CCD) is the depth in the ocean that the
rate at which calcareous sediments are supplied to the seabed equals the rate at which
those sediments dissolve. Below this depth, the skeletons of calcium carbonate
dissolve on the seafloor, so no calcareous oozes accumulate. Calcareous sediment
dominates the deep-sea floor at depths of less than about 4,500 meters (14,800 feet),
the usual calcium carbonate compensation depth. Calcareous oozes cover about 48
of the surface of deep-ocean basins.

Answer to Question 2

Dilute mixtures of sediment and water periodically rush down the continental slope in
turbidity currents. A turbidity current is not propelled by the water within it but by
gravity (the water suspends the particles, and the mixture is denser than the
surrounding seawater). The erosive force of turbidity currents is thought to help cut
submarine canyons. These underwater avalanches of thick, muddy fluid can reach the
continental rise and often continue moving onto an adjacent abyssal plain before
eventually coming to rest. The resulting deposits are called turbidites, graded layers of terrigenous sand interbedded with the finer pelagic sediments typical of the deepsea
floor. Each distinct layer consists of coarse sediment at the bottom with finer
sediment above, and each graded layer is the result of sediment deposited by one
turbidity-current event.