The Oceans - Chapter 1: Sea Floor Sediments Flashcards
Except for a few areas, the ocean floor is mantled with ____
sediments
Even though deposits of sand sized particles are found on the Atlantic floor, ___ is the most common sediment
mud
Sea floor sediment is divided into three broad categories:
lithogenous
biogenous
hydrogenous
True or false: all sea floor sediments are mixtures
True
This consists primarily of mineral grains that were weathered from continental rocks and transported to the ocean
Lithogenous sediment
Where are lithogenous sediments settled?
Near shore
True or false: there are no lithogenous sediments in the deep ocean
False
Why are there ample opportunities for chemical reactions to occur?
Fine particles remain suspended in the water
Why are deep sea sediments often red or brown
Because iron on the particle or the water reacts with dissolved oxygen and creates a coating of iron oxide (rust)
This sediment consists of shells and skeletons of marine animals and plants
Biogenous sediment
Biogenous debris is produced mostly by the ________ living in the sunlit waters
microscopic organisms
What are the most common biogenous sediments?
calcareous oozes (CaCO3)
True or false: calcareous ooze accumulates where depths are great
False; cold seawater has more CO2 and is more acidic so they will dissolve
This ooze is composed primarily of opaline skeletons of diatoms (single cell algae) and radiolarians (single cell animals)
Siliceous (SiO2)
What are phosphate rich materials in terms of deposits?
It is derived from the bones teeth and scales of fish and other organisms
This sediment consists of minerals that crystallize directly from seawater through various chemical reactions
Hydrogenous
What is a type of hydrogenous sediment that is has economic potential?
Manganese nodules
Rounded blackish lumps composed of a complex mixture of minerals that form slowly on floor of ocean basins
manganese nodules
Some scientists suggest that ___ animals living in and on sea floor are responsible for keeping the nodules at the surface
benthic
What is benthic?
The term benthic refers to anything associated with or occurring on the bottom of a body of water.
What kind of organisms produce a slight lifting effect that keeps nodules from being buried?
burrowing
One of the more interesting and important techniques for analyzing the earth’s climatic history is studying the ____ from the ocean floor
sediments
