STANDARD: Evaluate evidence of the past and current movement of continental and oceanic crust and the theory of the plate tectonic to explain the ages of crustal rock

How Do We Determine The Direction and Speed That Plates Move?
1)

How do we describe the movement of plates?
○ We measure location on Earth using longitude and latitude
○ Latitude is measured as the distance North or South of the equator
○ Longitude is measured as the distance East or West of the prime meridian

West or -

East or +
North or +
(West and South = ( - )
(East and North = ( + )

South or -

○ The directions that a plate is moving (based on longitude and latitude) are combined to determine the azimuth.
■ 0° points to north
■ 90° points east
■ 180° point south
■ 270° points west
○ To measure the azimuth you can measure the angle between the arrow and add/subtract it from one of the angles above.
○ In addition to describing the direction that plates move, we also have to measure how fast they are moving.
○ The speed the plates move is called a rate
■ rate = distance/time
○ The rate of plates is described in mm/yr which is equivalent to km/myr.
2)

One method we use to determine how plates move is to look for hot spots.
○ Shows how plates have moved move over millions of years
○ Hot spots form where narrow plumes of magma rise by connection from the core mantle boundary.
○ The magma continues to rise in the same same spot for millions of years.
○ IF this is true, what would the evidence look like?

3)