Chapter 23 Vocabulary Quiz

An abyssal hill refers to one of the small rolling hills found on the ocean floor, specifically next to the mid-ocean ridges. These hills are typically formed through various geological processes such as volcanic activity and tectonic movements. They are part of the larger abyssal plain, which is a flat and sediment-covered region on the deep ocean floor. Abyssal hills play a significant role in shaping the topography of the ocean floor and are often associated with the formation of underwater mountain ranges.

An abyssal plain refers to a vast, flat area on the ocean floor. These plains are located in the deepest parts of the ocean, typically beyond the continental rise. They are characterized by their smooth and featureless topography, with sediments that have accumulated over millions of years. Abyssal plains are formed by the deposition of fine-grained sediments, such as clay and silt, which settle on the ocean floor and create a flat surface. These areas are important for scientific research as they provide valuable insights into the geological processes occurring in the deep ocean.

An active continental margin refers to a type of continental margin where an oceanic plate is being subducted or forced underneath a continental plate. This type of margin is characterized by specific features such as a narrow continental shelf and a deep-sea trench. The subduction of the oceanic plate causes geological activity such as earthquakes and volcanic eruptions. This is in contrast to a passive continental margin, which does not experience subduction or significant tectonic activity.

Biogeneous sediments, also known as biogenous sediment or biogenous ooze, are sea-floor sediments that are primarily made up of the shells and skeletons of marine organisms. These sediments accumulate over time as the remains of dead organisms settle on the ocean floor. The shells and skeletons are composed of calcium carbonate or silica, and they can come from a variety of organisms such as plankton, coral, and mollusks. Biogeneous sediments are an important part of the marine ecosystem and provide valuable information about past ocean conditions and the evolution of marine life.

The continental margin refers to the underwater part of the continental crust. It includes the continental shelf, which is the shallow, gently sloping area close to the shore, and the continental slope, which is the steeper area that leads to the deep ocean floor. The continental margin is an important geological feature as it marks the transition between the continents and the ocean basins. It is also a site for various processes such as sediment deposition, erosion, and the formation of underwater canyons.

The correct answer is continental slope. The continental slope refers to the steep boundary between the continental shelf and the continental rise. It is a transition zone where the ocean floor drops off rapidly, creating a steep incline. This area is characterized by sediment accumulation and submarine canyons. The continental slope plays a crucial role in the formation of underwater features and the transportation of sediment from the continental shelf to the deep ocean.

A deep-sea trench, also known as a deep-ocean trench or deep ocean trench, is a long, narrow, steep-sided trough that runs parallel to continental margins or volcanic island arcs. These trenches are formed by the convergence of tectonic plates, where one plate is forced beneath another in a process called subduction. The subduction of the oceanic plate into the mantle creates a deep depression in the ocean floor, resulting in the formation of a deep-sea trench. These trenches are some of the deepest parts of the Earth's oceans, reaching depths of over 10,000 meters.

Echo sounding is a system that utilizes both transmitted and reflected sound waves to determine the distances to the ocean floor. This technique involves emitting sound waves into the water, which then travel down and bounce back when they encounter the seabed. By measuring the time it takes for the sound waves to return, the depth of the ocean floor can be calculated. This method is commonly used in oceanography and hydrography to map the topography of the seafloor and gather data about underwater features.

Hydrogenous sediment refers to sea-floor sediments that are formed through chemical reactions where minerals crystallize out of sea water. These sediments are called hydrogenous sediments.

A passive continental margin is formed when a continent is not located near a tectonic plate boundary. In this type of margin, there is no significant tectonic activity, such as subduction or volcanic activity. The east coast of the United States is an example of a passive continental margin because it is located on the eastern side of the North American Plate, away from any active plate boundaries. The margin is characterized by a wide continental shelf, a gentle slope, and a lack of major geological features like trenches or volcanic arcs.

A seamount, also known as a sea mount, is a cone-shaped undersea mountain that is formed by volcanic activity and rises high above the ocean floor. It is a geological feature that is found in the ocean and can vary in size and shape. The terms "seamount" and "sea mount" are used interchangeably to describe this type of underwater mountain.

The given correct answer, "terrigenous sediments" or "terrigenous sediment," refers to sea-floor sediments that originated from eroded minerals that were once part of continental rock. These sediments are typically composed of particles such as sand, silt, and clay that were transported by rivers, wind, or glaciers and eventually deposited onto the ocean floor. This process is responsible for the accumulation of terrigenous sediments in marine environments.