Chapter 13

What is a volcanic arc?

A row of volcanoes that forms on the overriding plate near a subduction zone.

What is a tablemount?

A seamount that grew above sea level, experienced wave erosion, and is now inactive.

What is the difference between a barrier reef and an atoll?

Barrier reefs surround an inactive volcano emerging above sea level, while atolls surround the previous location of a submerged volcano.

What would happen to Earth if ocean floor were created at divergent boundaries at a faster rate than it is destroyed at convergent boundaries?

The Earth would increase in volume.

Which process creates most submarine canyons?

Turbidity currents.

How is ocean depth calculated by sonar?

Ocean depth is calculated by the time it takes sound waves to travel from the ship to the seafloor and back to the ship again.

What feature(s) are measured when studying the bathymetry of the ocean?

Ocean depths and seafloor topography.

Which geologic features are associated with convergent boundaries?

Ocean trenches and volcanoes.

Why do coral reefs at the ocean surface grow away from seamounts over time?

Seamounts subside as tectonic plates move. Coral reefs grow away from the seamount in order to stay near the sunlight.

Which of the following is true regarding shallow subduction angles?

Sediment and seamounts are scraped from the downgoing plate to produce an accretionary wedge.

What type of ocean exploration technique is the best for determining potential oil and gas reservoirs?

Seismic reflection survey.

Which of the following describes a seismic reflection survey?

Seismic signals produced from an explosion travel to the ocean floor, penetrate some layers, and reflect back to a receiver.

If the subduction angle is steep, the overriding plate may undergo __________.

Subduction erosion.

Which of the following correctly describes the Atlantic and Pacific continental margins?

The Atlantic is a passive margin, and the Pacific is an active margin.

Where is the youngest ocean floor found?

Along the crest of mid-ocean ridges.

What is a seamount?

An active volcano that occurs along the crest of the mid-ocean ridge.

Which of the following mountain ranges are examples of continental arcs?

Andes and Cascades.

Turbidity curents travel from the shelf through __________, creating deep sea fans.

Canyons.

Which of the following statements about coral reefs and seamounts is most accurate?

Coral reefs at the ocean surface grow away from seamounts over time.

What is the main reason for the elevated position of the oceanic ridge system?

New, hot basalt is less dense here compared to the rest of the ocean basin.

Satellites record slight variations on the sea surface using radar. What do these slight variations represent?

Features on the seafloor.

Which is the correct order of coral reef development near seamounts?

Fringing reef, barrier reef, atoll.

Which geologic features are associated with divergent boundaries?

Mid-ocean ridges and continental rift valleys.

Choose the True statement regarding the continental shelf: -The shelf is the region located between deep sea fans and the abyssal plain. -The shelf lies beneath the deepest part of the ocean. -The continental shelf neighbors the continental rise. -The shelf represents the flooded portions of continents. -The shelf is always tectonically active.

The shelf represents the flooded portions of continents.