Plate Tectonics

The youngest material on the ocean floor is found where plates move apart. On which of the following structures is it usually found? A: plains B: mountains C: trenches D: ridges

D: central area of plates Where does most volcanic and seismic (earthquake) activity occur? A: abyssal plains B: continental plains C: plate boundaries D: central area of plates

According to most geologists, approximately how many millions of years old is the oldest material on the ocean floor? A: 360 B: 180 C: 10 D: 450

Which of the following mountains are formed by the collision of the Indo-Australian plate and the Eurasian plate? A: Appalachians B: Rockies C: Alps D: Himalayas

Alfred Wegener first theorized that continents had been joined in a single supercontinent called A: Eurasia B: Pangaea C: Micronesia D: Babylon

Several kinds of events change the features (shape of continents, etc Several kinds of events change the features (shape of continents, etc.) on Earth. Which of the following is NOT an example of an event that changes Earth's features: A: hurricanes B: earthquakes C: volcanoes D: comets

B: clouds of ash from the eruption limited sunlight for a few days In 1980, Mt. St. Helens (a volcano in Washington state) erupted. Which of the following would have had the greatest long term affect of this eruption on the local ecosystem? A: local herds of deer relocated for several years until their food source was reinstated B: clouds of ash from the eruption limited sunlight for a few days C: geophysicists were in the area for two weeks of study before the eruption D: airplanes were diverted from the area above the volcano in the weeks before and after the eruption

When an oceanic plate collides and sinks below a continental plate, what type of feature may result? A: ocean trenches B: subduction zone C: mountains D: all of the above

Subduction of an oceanic plate causes which of the following? A: recycling of the crust rocks as they melt back into the magma layer B: magma to flow into local river systems C: destruction of coral reefs D: none of the above

A: continental plates are moving faster In subduction zones, oceanic plates collide with and slide under continental plates. Why do oceanic plates slide under continental plates? A: continental plates are moving faster B: oceanic plates are moving faster C: oceanic plates are less dense than continental plates D: continental plates are less dense than oceanic plates

According to the model of plate tectonics, which layer is broken into plates? A: lithosphere B: asthenosphere C: hydrosphere D: core

New rock is being formed regularly as plates move away from each other under the ocean. A: True B: False

All rocks start out as molten magma. A: True B: False

Most earthquakes occur at convergence zones. A: True B: False

Mid-ocean ridges occur where plates are moving apart. A: True B: False