not the plate you eat off plate tectonics. core: iron/nickel, solid 7000 c asthensphere; liquid...
TRANSCRIPT
Not the Plate you Eat off
Plate Tectonics
Core: iron/nickel, solid 7000 C
Asthensphere; liquid 3000-6500 C
Crust: Silicate Rock 20-600 C
Lithosphere: silicate rock 100- 3000 C
Layers of the Earth
GPSGlobal Positioning System
• Satellite-based system for accurate location of points on earth
• Geoscientist have set up a network of targets all over the works in order to monitor the movement of lithosphere plates
GPS is technology that has only been around for about a decade
http://www.youtube.com/watch?v=vE9zZ3F5B5MGPS working
Computer Model (based on the GPS data)
• Can use a model to predict values from given information.
• The model’s values match the GPS data very well!
Predicted motionusing NUVEL1A Model
Actual Motion trackedusing GPS
So to further look at movement over a long period of time, the answer lies within rocks; magnetite (large amounts of iron)
Geoscientist study the magnetism of rocks that make up the sea floor
These rocks are grouped by which way their magnetic polarity points.
a)Magnetic polarity matches Earth’s magnetic north
b)Magnetic polarity is reversed, so the rocks magnetic polarity points south
In 1950’s scientists have noticed a pattered along ocean floor were new crust is being made!
• Running down the middle of nearly every ocean is a ridge of volcanic activity.
• One both sides of the ridge, the basalt that was formed has a set pattern of magnetism– One stripe has the north
pole of the magnets pointing north, the next stripe has the north pole of the magnets pointing south
– The pattern shows up on both sides of the ridge, and the width of the stripes are the same on both sides
Plate boundaries
• Divergent plate boundaries: are two plates move away from each other.
• When to continental crusts move away earthquakes, new lakes or streams
• Two oceanic crust move away= sea-floor spreading=new ocean crust forming
• httpt://www.youtube.com/watch?v=t-ck4KR-KU&feature=related
http://www.youtube.com/watch?v=GyMLlLxbfa4&feature=relatedBill Nye
• Convergent plate boundaries: two plates are moving toward each other; one of the two plates would have to go under the other one.
• When one plate dives under the other plate it is called: Subduction.
• Three kinds of subduction: • 1.oceanic to oceanic, • 2.continental to continental, • 3 oceanic to continental• http://www.youtube.com/watch?
v=ep2_axAA9Mw&feature=relate
Transform Boundaries: Plates that slide past one another.
The surface along which plates slide is called a transform fault.
http://www.learner.org/interactives/dynamicearth/structure.html
What drives the Plate
Density
• Density= (mass per volume)
• refers to how concentrated the mass in an object or material is.
• D= M/V • D=density (g/mL)• M= Mass (g)• V= volume (mL
Density =
Energy Flow
• When you heat objects you decrease density.
• Thermal convection: a pattern of movement in a fluid caused by heating from below and cooling from above It is a transfer of heat from bottom to top
Glass Bread Loaf Dish
Cup Sterno
Thermal Convection Experiment
Oil
Thyme
Flow
Tabletop
Thermal convection
http://www.youtube.com/watch?v=Kpoko_l34ZE&feature=related
History
• Alfred Wegener: German scientist that purposed the idea of continental drift.
• According to him, about 200 million years ago, all the continents were one big land mass called Pangea.