Ch 17 Review

• What 5 similarities on either side of the Atlantic Ocean provided evidence for continental drift?–Coastal Shapes–Rock Formations–Fossils–Ancient Climates–Glaciation

• If coal is found in a place that is now a cold, dry wasteland… what does that suggest?

• The climate of the area had changed… it was once more temperate and rainy

• The newest part of the ocean floor is found near what?

• Mid-ocean ridges

• What happens to plates at a transform boundary?

• They slide past one another

• What transfers thermal energy within the mantle?

• Convection currents

• The downward part of the convection current pulls plates…

• Towards one another

Early Observations

• As early as the 1500s, mapmakers noticed what about the continents?

• Matching coastlines

• Why was the continental drift hypothesis not widely accepted at first?

• The movement of the continents

• Compared to oceanic crust near deep sea trenches, the age of the crust near the mid-ocean ridges is?

• younger

• Compared to the crust near the mid-ocean ridges, the sediment deposits on the crust near the deep sea trenches?

• Is thicker

• The magnetic pattern on oceanic crust near a mid-ocean ridge is

• Symmetrically striped

• Each cycle of spreading and intrusion of magma at ocean ridges results in what?

• Formation of new crust

• Rift valleys are found at what type of plate boundary?

• divergent

• What process results in the formation of a deep sea trench?

• subduction

• Continental-continental collisions produce what?

• Very tall mountain ranges

• Oceanic-continental collisions produce what?

• Volcanic mountain ranges

• Oceanic-oceanic collisions produce what?

• Island arcs

• Crust is neither destroyed nor formed at which type of plate boundary?

• transform

• Convection currents that drive the movement of tectonic plates are located where?

• The mantle

• Wegener’s hypothesis that the world’s landmasses were once joined was called what?

• Continental drift

• The study of the earth’s magnetic record is known as what?

• Paleomagnetism

• A map line connecting points that have the same age are called what?

• isochrons

• Plate boundary where plates slide past each other…

• transform

• Plate boundary where plates move apart

• Divergent boundary

• Process whereby the weight of an uplifted ocean ridge pushes an oceanic plate towards a subduction zone.

• Ridge push

• Process whereby the weight of a subducting plate pulls the underlying lithosphere into the deep-sea trench.

• Slab pull

• Process where one plate descends beneath another?

• Subduction

• Not SEDUCTION--- those would be naughty plates =)

• Type of boundary where 2 plates come together

• convergent

• A change in the earth’s magnetic field is called a what?

• Magnetic reversal

• A landmass thought to have been comprised of all present-day continents was called what?

• pangaea

• A device that measures changes in earth’s magnetic field.

• magnetometer

• A device that uses sound to map the ocean floor

• sonar

• Deepest place on earth

• Marianas trench

• Theory that states that earth’s crust is broken into enormous slabs

• Plate tectonics

• the mechanism associated with plate movements

• convection

• Deep scratches found on rocks is evidence of what?

• glaciers.

• Where is the trench located?

• D

• Where is the ocean ridge located?

• E

• Where is subduction occurring?

• D

• Where is the newest rock located near?

• E

• Where is slab pull occurring?

• C

• Where is ridge push occurring?

• B

• Where is the convection current?

• A