Oceanography ch 4

For a sediment to be considered a biogenic ooze, what minimum percentage must be biological material?

30 percent

calcareous ooze

A calcareous ooze can be found at depths lower than 5,000 meters (3.1 miles) if it is buried under other sediment types. This protects the calcium carbonate from the water. Any calcareous ooze at the surface of the sediment profile at that depth will dissolve because it is below the calcite compensation depth (CCD)

What type of hydrogenous sediment is usually composed of salts?

Evaporite

How can a calcareous ooze be found at depths lower than 5,000 meters

It is buried under other sediment types

Increasing carbon dioxide concentrations in the atmosphere will cause what to happen to the calcite compensation depth?

It will become shallower.

What is required in order for a manganese nodule to form?

a nucleation object

A siliceous ooze is dominated by which microscopic algae?

diatom

What biological sediment deposit is often used in abrasives and absorbents?

diatomaceous earth

What often speeds up the descent of small particles to the ocean floor

fecal pellets

A calcareous ooze would be dominated by which of the following organisms?

foraminiferan

What resources are produced in the ocean floor by bacteria breaking down organic matter?

gas hydrates

A poorly sorted lithogenous sediment deposit was most likely transported by what?

glaciers

Carbonates

Carbonates are not formed in large quantities in temperate or polar areas because the climate conditions are not optimal for coral reef development.

Silica in the sediments is coming predominantly from diatoms and radiolarians.

Diatoms are photosynthetic algae that reside at the surface, and radiolarians are zooplankton that must feed at the surface. When large quantities of these organisms die, they sink to the bottom, and their hard parts contribute to the sediment.

quartz

Quartz is composed of the elements silicon and oxygen and is a hard mineral that can withstand abrasion. It is transported long distances away from the source rock and is found on beaches and continental margins around the world. Typically, sandy beaches are composed mostly of quartz.

A core section with a high amount of silica would most likely indicate what about the time it was deposited?

That there was a high amount of surface productivity.

Why are most deep-ocean lithogenous deposits composed of fine-grained sediments?

There is not enough energy to move larger grain sizes to the deep ocean.

gas hydrates

These are a compilation of water and natural gas that are pressed into a solid that can be burned. Organic material that makes its way to the sediments is decomposed in situ by bacteria. This must happen within the sediment in order for the gas to be created and confined. Otherwise, it will bubble to the surface of the ocean.

diatomaceous earth

This is composed of lithified siliceous ooze. Diatom frustules deposited on the ocean floor result in a siliceous ooze. Over time, lithification results in this becoming a rock that can be mined. Diatomaceous earth is used in many everyday materials, from toothpaste to cat litter.

A sediment deposit consisting of mostly large grain sizes (i.e., cobbles, pebbles) indicates that what energy regime exists in the area?

high-energy

An abyssal clay with a brownish-red color is rich in what element?

iron

What is the type of sediment that is derived from the continents?

lithogenous

The depth at which calcium carbonate begins to dissolve in the water is referred to as the:

lysocline

What can be used to differentiate cosmogenous sediments from other sediment types?

nickel content Cosmogenous sediment has high concentrations of nickel compared to lithogenic sediments found on Earth. The large majority of nickel sank toward the core during the cooling of the planet because it was denser than the surrounding material. Sediments that have a higher nickel concentration than normally found in the crust and in other sediments are designated as cosmogenous.

What is the area of study in oceanography that uses marine sediments to determine past changes in the ocean environment, such as water temperature or circulation?

paleoceanography

What is the major mineral component of lithogenous sediment?

quartz

The device upon which you are reading this question has components made from resources from the ocean floor. What are they called?

rare earth elements

What method of sediment collection achieves the deepest penetration?

rotary drilling

What is the most significant mode of transport of lithogenous sediment?

water