Oceanography Exam Study Guide Flashcards

Terms Definitions
Continental Slope
Sediment precipitated from seawater
Siliceous Sediments
• Makeshellsoutof
SiO2 (silica) Examples
• Diatoms – Single celled algae – Photosynthetic
• Radiolarians – Single celled
Gas Hydrates
• Read 256-258
• Solidformofmethane
• Found in sediment on continental shelf and slope
Dominant high latitudes ocean locations - single celled algae and photosynthetic
Formed from rain and snow
Are deep-sea trenches found at convergent or divergent plate boundaries?
The distance between crests of waves
What is this a picture of?
Sediment is precipitated from seawater
Hydrogenous Sediment
Are abyssal plains more extensive on the floor of the Atlantic or of the Pacific?
animals that actively swim rather then drift in the current
the density of water increases when the salinity ____
a long steep-sided depression in the ocean floor
Ocean Sediments
• Various materials settle through the water column and accumulate on the ocean floor
• Layers represent a record of Earth history, including:
– Movement of tectonic plates
– Past changes in climate
– Ancient ocean circulation patterns
– Cataclysmic events
Cosmogeneous sediment
• Comes from space
• Meteorites: small % of seafloor sediments, infrequent burns up in atmosphere
• Space dust: micro-filaments that fall through atmosphere
• Tektites a form of rock that is melted or has melted when hit by a meteorite
Continental Crust
• Mostlygranite
• Thicker
• Less Dense
Distribution of Lithogenous sediment
• Lithogenous sediment occurs as:
– Neritic (nearshore) deposits
• Beaches
• Continental shelves
• Turbidites
• Glacial-rafted debris
– Pelagic (deep ocean floor) deposits
• Abyssal clay
• Liquid water that changes into water vapor without boiling
According to the video "Noah's Ark," how long ago did the Black Sea change from a fresh water lake to an inland sea?
7540 years
is the mid atlantic ridge an example of divergent or convergent plate boundary?
abyssal plain
flat seafloor area, formed by the deposition of sediments
The zone of the ocean in which salinity increases rapidly with depth.
of or existing at or near the geographic equator
a seamount is a mountain whose peaks that dont break the surface.
Sediment that has its source from life
Biogeneous Sediment
Which plate boundary is closest to Utah going East?
Mid-Atlantic Ridge
One of the organisms that make up Calcareous Ooze
Oceanic-Oceanic Subduction Zone
• Denser plate subducts under less dense plate
• Deep sea trench forms where 2 plates meet
• Subducting plate partially melts- creating a chain of volcanoes parallel to the trench called a volcanic island arc
Pacific Plate
The Pacific Plate moves over the mantle plume. Whichever part of the plate is over the mantle plume has active volcanoes. The volcanoes that have moved away from the mantle plume are extinct.
Hot Spots
• Mantle plume- stationary column of heat from mantle
• Platemovesovertop of mantle plume
• Spotoncrustover mantle plume is called a “Hot Spot”
Low lying flat areas. Covered as water at least part of the year.
What are the characteristics of passive continental margins?
lack major tectonic activity
What ion in seawater serves as a pH buffer?
What is lithosphere?
The outer layer of the earth's structure including the crusts and upper mantle, its a major component in plate tectonic movement
diurnal tides
one high tide and one low tide daily
the crest is the tobmost part of the wave. (above the Trough)
- where two plates move away from each other resulting in new crust being formed.
These organisms make up a Siliceous Ooze
• Diatoms
• Radiolarians
– Ocean on one side- if you are between the ocean and the continent- you must be at the beach- look for a boundary on a coastline
What is the continental shelf?
A gently sloping depositional surface extending from the low water line to the depth of a marked increase in slope around the margin of a continent or island.
Give an example of a slow moving ridge
mid atlantic ridge
surface currents
Currents at the top layer of the ocean caused by winds
Annual Sediment Transport
• Greatest average is the Houng Ho River
• All factors equal
a. greater sediment input into ocean by rivers is in summers
b. tropics transport greater sediment load than a river located at high altitudes
Where are methane hydrate deposits located?
Continental shelf and slope deposits
Hot Spot
Forms when a plate moves over a mantle plume (NOT a plate boundary)
Sea-Floor Spreading
• Plates in the middle of the ocean move away from each other
• ProposedbyHarry Hess
What are the two most abundant ions in seawater?
Sodium and Chloride
BIOGENOUS SEDIMENTS -- produced directly by organisms
Warm, shallow seas -- shells of animals (clams, corals)
Open ocean (deep sea) -- "shells" of microscopic "plankton"

Components of sediment-producing plankton:

1. CaCO3 (calcium carbonate)

Coccolithophores Foramifera

2. SiO2.(+nH2O) (opaline silica)

Diatoms Radiolarians

Biogenic "oozes" -- > 30% of biogenous sediment

Calcareous ooze
Siliceous ooze
Describe the direction of motion along a seafloor transform fault.
Across a transform fault, two lithospheric plates are moving in opposite directions. They are actual plate boundaries.
Convergent Plate Boundaries Type 3: Continental-Continental Convergent
• Continental plate collides with a continental plate
• No Subduction
• No Volcanoes
• Collidingcrustpushes upward creating mountain ranges

A- Alps H- Himalayas
How do the oceans affect the atmosphere?
The temperature of one
affects the temperature of the other. Wind in the atmosphere affects ocean waves and currents.
Give the correct order of marine provinces from the coast out to the mid-ocean ridge
1. continental margins, 2. deep ocean basins, 3. mid-ocean ridge
What are the two most abundant gasses in the atmosphere and the percentage by each volume?
Nitrogen at 78%
oxygen at 21%
What do the two relatively flat areas on the hypsographic curve represent?
various intro plate elevations on land and underwater
In which ocean (Atlantic or Pacific) are there more Abyssal Plains? In which ocean are there more trenches? Why?
There are more abyssal plains in the Atlantic because in the Pacific the trenches trap the sediment as it comes off shore. The sediment gets stuck in the trenches and does not reach the open ocean basin floor and thus does not have the opportunity to create abyssal plains.
What method is most frequently used to investigate sediment and rock layers of the sea floor?
Multi beam echo sounding and side scan sonar
Why is the polarity of water important?
Because water is polar, it has a net positive charge on one side and a net negative charge on the other side. This allows water molecules to bond via hydrogen bonding to other water molecules. It also allows other substances like sodium to dissolve easily in water.
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