C HAPTER 2 O CEANS C ONTROL THE W ATER C YCLE Section 2.1:
Ocean Basins Section 2.2: Ocean Currents Section 2.3: Waves and
Tides
Slide 2
S ECTION 2.1: T HE O CEANS OF THE W ORLD
Slide 3
S ECTION 2.1: C ONTINENTAL D RIFT The phenomenon of the
continents moving away/toward one another is called Continental
Drift. Continental Drift.
Slide 4
S ECTION 2.1: S HAPING THE O CEAN B ASINS Four Factors lead to
shaping the Ocean Floor as we know it today 1. Tectonic Plates 2.
Volcanic Action 3. Glaciation 4. Erosion
Slide 5
S ECTION 2.1: S HAPING THE O CEAN B ASINS Tectonic Plates
Separated continents and defined the ocean basins Tectonic plates
continue to move today North America and Europe are moving further
apart by 3 cm each year! Did you know?
Slide 6
S ECTION 2.1: S HAPING THE O CEAN B ASINS Volcanic Action (and
Tectonic Plates) Volcanoes formed by the movement of the tectonic
plates When two plates move toward one another, there is a massive
amount of energy and friction. Large amounts of pressure and heat,
melt and crack the crust The crack allows for hot rock and magma to
escape
Slide 7
S ECTION 2.1: S HAPING THE O CEAN B ASINS Volcanic Action Water
trapped in volcanic materials was released as water vapour like
steam from a kettle! The vapour cooled, condensed, and fell back to
earth Water pooled in the lowest parts of the Earths surface (the
ocean basins)
Slide 8
S ECTION 2.1: S HAPING THE O CEAN B ASINS Volcanic Action (and
Tectonic Plates) As tectonic plates move away from one another hot
magma is exposed to the surface. If the magma is exposed
underwater, it quickly cools and forms an undersea mountain chain
called an ocean ridge
Slide 9
S ECTION 2.1: S HAPING THE O CEAN B ASINS Volcanic Action (and
Tectonic Plates) As Oceanic Plates meet Continental Plates the
denser Ocean Plate is forced to bend underneath the less dense
Continental Plate. An ocean trench is formed The Marianas Trench is
the worlds deepest at 11km!Marianas Trench Did you know?
Slide 10
S ECTION 2.1: S HAPING THE O CEAN B ASINS Glaciation* A source
of erosion in Continental Drainage Systems As Glaciers expand and
contract fresh water drainage sources are affected (ie. Evaporate
or Flood) Sea levels may rise/fall * not in your textbook
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S ECTION 2.1: S HAPING THE O CEAN B ASINS Erosion* Aided in the
development of continental drainage systems Minerals and other
materials are removed and deposited in Ocean Basins (ie. Runoff)
Aids in the development of Abyssal Plains * not in your
textbook
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S ECTION 2.1: T HE O CEAN F LOOR C
Slide 13
Use your textbook or the internet to find definitions for the
following terms: Ocean Ridge Ocean Trench Abyssal Plain Continental
Slope Continental Shelf Continental Margins
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S ECTION 2.1: E XPLORING THE O CEAN Use your textbook or the
internet to record the How? and What? for each method of underwater
Exploration (pg 44 47 in Text) Sonar Mapping Satellites
Submersibles Deep Sea Cameras Diving
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S ECTION 2.2: O CEAN C URRENTS An ocean current is a large
amount of ocean water that moves in a particular and unchanging
direction.
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S ECTION 2.2: O CEAN C URRENTS The Gulf Stream Carries warm
water from the tropics North and across the Atlantic The Labrador
Current Carries colder water from the North to the South
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S ECTION 2.2: O CEAN C URRENTS The combination of warm and cold
waters create a nutrient rich area (Grand Banks)
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S ECTION 2.2: O CEAN C URRENTS Two Types of Ocean Currents 1.
Surface Currents Flow between 100 200 m from the surface of the
ocean Affected by Winds, the Earths Rotation and Continental Shape
1. Deep Currents Flow below 200m Affected by Water Temperature and
Salinity
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S ECTION 2.2: S URFACE C URRENTS 1. The Effect of Wind Major
wind patterns always move water in a constant direction Wind caused
by uneven heating and creation of high and low pressure
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S ECTION 2.2: S URFACE C URRENTS 2. The Earths Rotation Winds
and current redirected due Earths rotation (this is called the
Coriolis Effect ) Coriolis Effect Northern Hemisphere: Clockwise
Southern Hemisphere: Counter-Clockwise
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S ECTION 2.2: S URFACE C URRENTS 3. Continental Shape Currents
are forced to deflect when they meet a solid object (ie. the
continents)
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S ECTION 2.2: D EEP C URRENTS 1. Water Temperature Water
temperature is separated into 3 layers: mixed, thermocline and deep
Thermocline: the depth at which the energy from the sun has no
effect on temperature (200m 1000m below) Cold water is more dense
and therefore sinks Sinking masses of cold water form density
currents
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S ECTION 2.2: D EEP C URRENTS 2. Salinity Water with higher
salinity levels is more dense Areas with added fresh water will be
less dense (ie. Mouths of rivers, Glaciers, etc.) Areas with high
levels of evaporation will be more dense Areas where sea water can
freeze will produce salty water
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S ECTION 2.2: U PWELLING When water moves vertically from the
ocean floor to the surface it is called upwelling Caused when:
Strong winds blow offshore displacing surface water Deep, cold
water then rises to replace surface water Bring nutrients from the
ocean floor to the surface Helps plant growth and attracts marine
life
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S ECTION 2.3: W AVES AND T IDES What is a Wave? The movement of
water that transfers energy Created by steady winds (speed and
duration) moving surface water, forming large ripples Stronger
Winds = Larger Waves Average winds: 2m 5m waves Hurricane: 30m+
waves The steady movement of smooth waves are called swells
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S ECTION 2.3: W AVES AND T IDES The Anatomy of a Wave Science
and Technology Focus; Ocean in Motion: Wave Characteristics
http://www.onr.navy.mil/focus/ocean/motion/waves1.htm Crest: The
highest part of a wave Trough: The lowest part of a wave Wave
Length: The distance from one crest to the next
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S ECTION 2.3: W AVES AND T IDES Breaking Waves Water particles
move in a circular motion as wave passes As waves approach the
shoreline Wavelength - decreases Wave Height - increases Trough
speed is slowed due to friction As a wave tumbles to the shore it
is called a breaker USGS Geology in the Parks; Water + Wind = Waves
http://geomaps.wr.usgs.gov/parks/sea/gwave.html
Slide 28
S ECTION 2.3: W AVES AND T IDES Tsunamis A large ocean wave
caused by an earthquake, volcanic eruption or landslide on the
ocean floor Wavelength: 150 km Speed: 800 km/hr Japan Today:
http://www.theatlantic.com/infocus/2013/03/japan-earthquake-2-
years-later-before-and-after/100469/ In 2011, an earthquake off the
coast of Japan created a Tsunami that killed 19000 people.
