S ECTION 2.1: C ONTINENTAL D RIFT The phenomenon of the continents moving away/toward one another is called Continental Drift. Continental Drift.
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
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?
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
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 part’s of the Earth’s surface (the ocean basins)
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
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 world’s deepest at 11km!Marianas Trench Did you know?
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
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
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
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
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.
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
S ECTION 2.2: O CEAN C URRENTS The combination of warm and cold waters create a nutrient rich area (Grand Banks)
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 Earth’s Rotation and Continental Shape 1. Deep Currents Flow below 200m Affected by Water Temperature and Salinity
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
S ECTION 2.2: S URFACE C URRENTS 2. The Earth’s Rotation Winds and current redirected due Earth’s rotation (this is called the Coriolis Effect ) Coriolis Effect Northern Hemisphere: Clockwise Southern Hemisphere: Counter-Clockwise
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)
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
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
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
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
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
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
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.