What was Wegener’s hypothesis called? Continental drift

Africa and South America Which two continents seemed to fit together so well and supported the continental drift theory? Africa and South America

What are two pieces of evidence that Wegener had to support his drift theory? The Shape of the Continents Coal in Antarctica Matching rock types on the coasts Matching Fossils on the coasts

List and describe the two technologies that Wegener could have used to support his drift theory but didn’t have available at the time? Magnetometer: Pale magnetism showed that the seafloor was spreading Sonar: Showed that the seafloor was not flat

Why was Wegener’s theory rejected? He didn’t have a “Driving Mechanism” for how the continents can move.

What idea about the ocean floor did Sonar help disprove? The old idea was that the seafloor was flat. The sonar showed that it had mountains and trenches (not flat at all!)

Sediments close to the ridge are younger and make thinner layers. How do sediments close to the ridge vary from sediments far from the ridge? Sediments close to the ridge are younger and make thinner layers.

What is the difference between normal and reversed polarity? Normal is today’s magnetic field orientation and reverse is the opposite.

Briefly explain plate tectonics? The Earth’s upper crust is broken into large slabs called “Plates”. These plates move around due to convection cells that are occurring underneath them in the Mantle. These plates interact with each other at plate boundaries. There are frequently volcanoes and earth quakes at these boundaries.

Briefly explain how the continents move? The continents (Thick slabs of granitic crust) are riding on top of the ocean crust (thinner more dense layer of basalt). As the new ocean crust forms at divergent plate boundaries, the old crust is pushed away and the continents go along for the ride.

Compare and contrast the three types of convergent boundaries? Ocean to ocean (Subduction zones form) Ocean to continental (Subduction zones form) Continental to Continental (Mountain building)

Early map makers thought continents might have moved based on their observations of…? Matching coast lines

What was the name of all of the continents stuck together? Pangaea

Sonar and magnetometer What two technologies could Wegener not use because it was invented yet? Sonar and magnetometer

True or False, land dwelling animals such as Cynognathus and Lystrasaurus were apart of the fossil evidence that Wegener used? True

What did the fresh water reptile fossils indicate to Wegener? Since they were found on the coasts of South America and Africa, and because the animal could not swim across such a vast distance, that the two coasts must have been much closer

Based on the Glossopteris fossils, Wegener concluded what? Since these fossils were found in South America, India and Antarctica, it was unlikely that an area that large had a single climate. He also reasoned that this plant required a more temperate climate, so areas like Antarctica must have been closer to the Equator.

Besides the Glossopteris plant fossil, what was found in Antarctica that lead Wegener to believe it was once near the equator? Coal

What made Wegener think that landmasses drifted away from the south pole? Glacial deposits, because at the current location for areas like Africa, India and Australia, it is too warm for glaciers like that to form.

Why did most scientists reject Wegener’s hypothesis? He couldn’t explain how a continent could move. Additionally, a continent made of granite could not push through a sea floor of basalt without breaking up.

What uses sound waves to measure depth? Sonar

Maps made from Sonar and Maps made from Sonar and data led to the discovery of ocean ridges and deep sea trenches? Magnetometer

What is the study of the magnetic record preserved in the Earth’s rocks called? Paleomagnetisim

True or False, earthquake activity and volcanism are common along ocean ridges?

What theory explains that the Earth’s continents move because they ride atop ocean crust as it moves away from ocean ridges? Seafloor Spreading

An Isoline that connects areas of equal age. What is an isochron? An Isoline that connects areas of equal age.

What happens to the thickness of sediments as distance from the mid ocean ridge increases? Why does this happen? The thickness increases because more time has gone by since the crust has been made so more weathering has taken place.

Where is the youngest rock in the ocean located? At the ridges (divergent plate boundaries) where the new crust is made.

What does it mean if an area has a reversed polarity? It has the opposite polarity of today

Minerals containing acts like a small compass inside the rock, and records the Earth’s fields over time? Iron

Which theory states that Earth’s crust and rigid upper mantle move in different directions and at different rates over Earth’s surface? Plate Tectonics

Tectonic plates interact at places called plate ? Boundaries

Areas where plates move apart are called ? Divergent

Where are most divergent boundaries found? The ocean floor

What occurs along divergent boundaries? New crust forms, and there are ridges that form due to the heated crust.

The mid ocean ridge is an example of what kind of boundary? Divergent

Places where plates come together are called? Convergent plate boundaries

How are convergent boundaries classified? Ocean to ocean Ocean to continental Continental to continental

What type of igneous rock is the ocean crust made of? Basalt

What is created when two ocean plates converge? Subduction Zones

What can form if an eruption occurs at when two ocean plates converge? Volcanically formed islands called Volcanic island arcs

At which boundary will a rift valley form? Divergent plate boundary

At which boundary will a trench form? Convergent

At which boundary do the plates slide past each other? Transform

What is the transfer of thermal energy called that moves the plates? Convection

Where does ridge push occurs? Divergent plate boundaries (or ridges)

Where does slab pull occur? Convergent plate boundaries or subduction zones

What is slab pull similar to at home? When part of the comforter slides off of the bed and it pulls the rest of it off and on to the floor.

What does asthenos mean in Greek? Weak