(1) Earth Science Review: Oceans & Coasts

How much of Earth’s water is in the oceans?

• 97.2%

• Covers 71% of Earths Surface

What are the THREE zones of a passive continental margin?

• Continental Shelf

• Continental Slope

• Continental Rise

Continental Shelf?

• Underlain by continental crust

• Shallow water (mostly 0-200m deep)

• Very gentle slope

Continental Slope?

• Transition from continental crust to oceanic crust

• Rapid increase in water depth

• Steeper slopes (5 to 25 degrees)

• Canyons eroded by turbidity currents

Continental Rise?

• Transition into deep ocean

• Gentle slope

• Sediment from adjacent continent

Abyssal Plains?

• Deep-sea flat areas

• Very flat

• Thick layers of sediment

Turbidity Current?

Underwater flow of sense muddy water

Longshore Current?

Water movement along beach

• Waves wash up at angle

• Water flows back down steepest slope

• Moves sand along shore

Seamounts?

Submerged mountain

Volcanic Islands?

If built above sea level

Guyots?

Flat-topped seamount, caused by wave erosion

Volcanic arcs?

Curved chain of volcanoes that forms above a subduction zone - one tectonic plate skinks beneath another

Spits?

Sand & Gravel deposit, one end connected to land

• Shows direction of longshore current

Baymouth bars?

Sand & gravel deposit, both ends connect to land

Groins?

Short wall across beach

Jetties?

Long wall extending into open water

Can you infer the direction of a longshore current from spits, groins, and jetties?

Yes

• Spit: Toward the pointed end

• Groin: From sand-rich side → sand-poor side

• Jetties: From sand-rich side → sand-poor side

High tide? Causes?

• 2 of each per day

• Heights may or may not be equal

• Cycle period is 12.42 hour

  • When rotate INTO a bulge

Low tide? Causes?

• 2 of each per day

• Heights may or may not be equal

• Cycle period is 12.42 hour

  • When rotate OUT of bulge

Spring tides? Causes?

• 2 of each intervals per month

• Interval of larger tidal range

  • When Sun’s gravity enhances bulges

Neap tides? Causes?

• 2 of each intervals per month

• Interval of smaller tidal range

  • When Sun’s gravity reduces bulges

What causes the large tidal range in the Bay of Fundy?

Due to funnel-shaped bay

What causes water waves to be larger?

• Wind blowing faster

• Wind blowing for longer time

• Wing has a longer fetch (blows over longer distance)

When during the year are beaches narrower? Why?

Winter - due to more storms

How is moving air in the northern hemisphere affected by the Coriolis effect?

• Affected motion over long distances

• Turn to right in NH

0 Degrees in the Three-cell model?

Hot and Humid

30 Degrees in the Three-cell model?

Hot and Dry

60 Degrees in the Three-cell model?

• Cool & Humid

90 Degrees in the Three-cell model?

Cold and Dry

Ocean Gyres? What drives them?

• Large, circular surface ocean currents

• Clockwise in NH, counter-clockwise in SH

• More complex near land

• Move warm water polewards, cold water to tropics

• Collect floating trash too

Gulf Stream?

• Part of N. Atlantic gyre

• Warm water current, up to 2.5 m/s (5.6 mph)

• Connects with deep ocean circulation

Thermohaline circulation? What drives it?

• Oceans “conveyor belt”

• Driven by differences in water’s density, controlled by temperature and salinity