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22 terms

Chapter 14

The Ocean Floor
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Oceanography
science that draws on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the world ocean.
Bathymetry
measurement of ocean depths and the charting of the shape or topography of the ocean floor.
Sonar
an acronym for sound navigation and ranging. It is also referred to as echo sounding.
Submersibles
small underwater crafts used for deep-sea research.
Continental margin
zone of transition between a continent and the adjacent ocean basin floor.
Continental shelf
gently sloping submerged surface extending from the shoreline.
Continental slope
steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf.
Submarine canyon
seaward extension of a valley that was cut on the continental shelf during a time when sea level was lower—a canyon carved into the outer continental shelf, slope, and rise by turbidity currents.
Turbidity current
the downslope movement of dense, sediment-laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension.
Continental rise
gently sloping surface at the base of the continental slope.
Ocean basin floor
the area of the deep-ocean floor between the continental margin and the oceanic ridge.
Abyssal plain
very level area of the deep-ocean floor, usually lying at the foot of the continental rise.
Seamount
an isolated volcanic peak that rises at least 1000 meters above the deep-ocean floor, and a guyot is an eroded, submerged seamount.
Mid-ocean ridge
found near the center of most ocean basins. It is an interconnected system of underwater mountains that have developed on newly formed ocean crust.
Seafloor spreading
the process by which plate tectonics produces new oceanic lithosphere at ocean ridges.
Terrigenous sediments
consist primarily of mineral grains that were eroded from continental rocks and transported to the ocean.
Biogenous sediments
consist of shells and skeletons of marine animals and algae.
Calcareous ooze
thick, common biogenous sediment produced by dissolving calcium carbonate shells.
Siliceous ooze
biogenous sediment composed of silica-based shells of single-celled animals and algae.
Hydrothermal sediment
consists of minerals that crystallize directly from ocean water through various chemical reactions.
Gas hydrates
compact chemical structures made of water and natural gas.
Manganese nodules
hard lumps of manganese and other metals (like cobalt, copper, and iron) that precipitate around a small object.