Earth Science

Tectonic plates are huge moving pieces of the Earth's crust and there are different mechanisms that can explain the causes of their movement. Which of the following are the causes of plate movement?

• a. radiation and conduction

• b. Convection currents and gravity

• c. Mantle convection and diffusion

• d. Gravity and sublimation

There are three types of plate boundaries. Each type is associated with different geological features. How are mountain ranges formed by plate tectonics?

• a. It is formed when two tectonic plates move away from each other.

• b. Mountain ranges are formed when two continental plates converge, neither of the buoyant plates are able to give way and subduct beneath the other.

  

• c. Mountain ranges are formed when one of the plates (oceanic crust and lithospheric mantle) is pushed, or subducted, under the other and often it is the older and colder plate that is denser and subducts beneath the younger and warmer plate.

• d. It is formed when two tectonic plates slide past one another.

The seven major plates are Pacific, North American, Eurasian, African, Antarctic, Indo- Australia, and South American plate. Which of the following statements is true about Pacific plate?

• a. This plate extends all the way over the North Pole and even

  contains Siberia and the northern island of Japan.

• b. This plate is sandwiched between the North American and African Plates on the north and west sides.

• c. This plate is the largest

  and it stretches all the way along the west coast of North America to the east

  coast of Japan and Indonesia.

• d. This plate is surrounded by parts of the African, Australian, Pacific, and South American plates.

Scientists did not accept Wegener’s theory of continental drift. Why was Wegener's theory rejected by geophysicists of the 1920's?

• a. He could not explain how or why the continents were drifting

• b. He could not provide evidence for the continental drift

• c. The presence of a continent directly over the south pole

• d. The earth was then thought to be too young for such movements

The Ring of Fire, also referred to as the Circum-Pacific Belt, is a path along the Pacific Ocean characterized by active volcanoes and frequent earthquakes. Which of the following statements is true about the Pacific Ring of Fire?

• a. The Ring of Fire is home to 97% of the world's volcanoes and 99% of its earthquakes.

• b. The Ring of Fire is home to the deepest ocean trench, called the Puerto Rico Trench and it is located east of Guam, the 4-mile-deep Puerto Rico Trench formed when one tectonic place was pushed under another.

• c. The Ring of Fire is a roughly 90,000-mile chain of volcanoes and seismically active sites that outline the Pacific Ocean.

• d. The Ring of Fire is the result of plate tectonics and it is a string of underwater volcanoes and earthquake sites around the edges of the Pacific Ocean.

Plate tectonics is a scientific theory that explains how major landforms are created as a result of Earth's subterranean movements. Plate plates are able to move because Earth's lithosphere has greater mechanical strength than the underlying asthenosphere. Which of these is NOT the result of plate tectonics?

• a. earthquake distribution

• b. polar wander

• c. formation of new oceans

• d. convection in the outer core

How did Wegener’s hypothesis of continental drift differ from the current theory of plate tectonics?

• a. Wegener’s hypothesis was supported with evidence from fossils and rock formations.

• b. According to Wegener’s hypothesis, South America and Africa were father apart in the past.

• c. According to Wegener’s hypothesis, the driving force for plate tectonics was mantle convection.

• d. Wegener’s hypothesis was based on the assumption that the continents were much younger than the ocean basins.

A student finds a map of the tectonic plates in a reputable geology resource. The map is completely different from the map on the NOAA website. Some plates are of different shapes and sizes, some are in different locations, and some do not even exist at all. What is the most reasonable explanation for this?

• a. The map represents the plates as they existed 200 million years ago.

• b. The approximate depth inside the Earth where the hotspot magma originates.

• c. There is a random distribution of rocks of various ages on the islands.

• d. Sediments from continents are carried to the ocean in rivers and spread out on the ocean floor.

Scientists collect a set of core samples from the ocean floor and plot the age of the basalt on a map. They notice that the age of the basalts increases steadily from east to west until a certain point and then starts to decrease again. The scientists then collect samples along series of parallel tracks and notice the same pattern along each track. Which topographic feature most likely lies along the ocean floor where the rocks begin to decrease in age?

• a. A deep submarine trench

• b. Underwater landforms

• c. Abyssal plains

• d. Continental shelf

The theory of sea floor spreading was developed by an American geophysicist in 1962. What technique was used to do this?

• a. Seismic survey

• b. Magnetic survey

• c. Echo sounding survey

• d. Gravity survey