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| an interdisciplinary science that draws on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the world ocean |
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| a nickname for the Earth because the view from space shows largely ocean |
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| Northern Hemisphere because there is 61% water surface and 39% land |
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| Southern Hemisphere because there is 81% water surface and only 19% land |
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| largest ocean and the largest single geographic feature on the planet |
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| about half the size of the Pacific Ocean and not as deep |
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| slightly smaller than the Atlantic Ocean but about the same depth |
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| only 7% the size of the Pacific Ocean and only a little more than one-quarter deep as the rest |
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defined by the meeting of currents near Antarctica, it is the portions of the Pacific, Atlantic, and Indian Oceans south of about 50ยบ south latitude
also called the Southern Ocean |
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| the measurement of ocean depths and the charting of the shape or topography of the ocean floor (bathos = depth, metry = measurement) |
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| an acronym for sound navigation and ranging |
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| first devices that used sound to measure water depth; they work by transmitting a sound wave (called a ping) into the water to produce an echo when it bounces off any object |
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| torpedo-shaped instruments are towed behind a ship where they send out a fan of sound extending to either side of the ship's track |
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| torpedo-shaped instruments used in sidescan sonar |
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| high-resolution multi-beam sonar |
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| regularly provide detailed bathymetric (water depth) data; helps map the features of the ocean floor |
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| equipped on satellites to measure subtle ocean surface irregularities by bouncing microwaves off the sea surface |
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| seismic reflection profile |
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| strong low-frequency sounds are produced by explosions (depth charges) or air guns; the sound waves penetrate beneath the seafloor and reflect off the contacts between rock layers and fault zones |
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| passive continental margins |
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| found along the coastal areas that surround the Atlantic Ocean; not associated with plate boundaries and experience very little volcanism and few earthquakes |
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| active continental margins |
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| occur where oceanic lithosphere is being subducted beneath the edge of a continent; the result is a relatively narrow margin consisting of highly deformed sediments |
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passive continental margin
(features) |
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| the continental shelf, the continental slope, and the continental rise |
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| a gently sloping, submerged surface extending from the shoreline toward the deep-ocean basin; a flooded extension of the continents |
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| large valleys running from the coastline into deeper waters that dissect continental shelves; they are seaward extensions of river valleys on the adjacent landmass |
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| a relatively steep structure that marks the boundary between continental crust and oceanic crust |
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| deep, steep-sided valleys that cut into the continental slope and may extend across the entire continental rise to the deep-ocean basin |
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| periodic down-slope movements of dense, sediment-laden water that are often referred to as "underwater avalanches" |
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| deposits from turbidity currents consisting of sand, silt, and clay |
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| a phenomenon when turbidites decrease in grain size from size from top to bottom |
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| in regions where trenches do not exist, the steep continental slope merges into a more gradual incline |
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| muddy currents emerge from the mouth of a canyon onto the relatively flat ocean floor and deposit sediment |
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| deep-sea fans have the same basic shape that form at the foot of steep mountain slopes on land |
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| active continental margins |
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| located primarily around the Pacific Ocean in areas where oceanic lithosphere is being subducted beneath the leading edge of the continent; sediments from the ocean floor and pieces of oceanic crust are scraped from the descending oceanic plate and plastered against the edge of the overriding continent |
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chaotic accumulation of deformed sediment and scraps of oceanic crust
(ad = toward, crescere = to grow) |
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| 30% of the Earth's surface that lies between the continental margin and the oceanic ridge |
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deep, incredibly flat areas found in deep-ocean basins
(a = without, byssus = bottom) |
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| submarine volcanoes which may rise hundreds of meters above the surrounding topography |
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| long, relatively narrow creases in the seafloor that form the deepest parts of the ocean; found in deep-ocean basins |
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| arc-shaped row of active volcanoes that often parallel deep-ocean trenches |
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| continental volcanic arcs |
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| located parallel to trenches that lie adjacent to continental margins |
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| the large number of trenches and associated volcanic activity along the margins of the Pacific Ocean |
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| instruments that generate signals designed to penetrate far below the ocean floor |
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submerged, flat-topped seamounts
also known as tablemounts |
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| generated by mantle plumes, they resemble the flood basalt provinces found on the continents |
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along well-developed divergent plate boundaries, the seafloor is elevated, forming a broad linear swell
also know as mid-ocean ridge |
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| not narrow and steep as the term implies; they have an average width of about 1,000 km (620 miles) and have the appearance of a broad elongated swell that often exhibits rugged topography |
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| deep down-faulted structures; exceed 50 km in width and 2,000 meters in depth, they contain faulted and tilted blocks of oceanic crust, as well as volcanic cones that have grown upon the newly formed seafloor |
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| composed of fine-clay particles, it is the most common sediment of the ocean ridge region |
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consists primarily of mineral grains that were weathered from continental rocks and transported to the ocean
(terra = land, generare = to produce) |
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consists of shells and skeletons of marine animals and algae
(bio = life, generare = to produce) |
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consists of minerals that crystallize directly from seawater through various chemical reactions
(hydro = water, generare = to produce) |
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hard shells from dead organisms that constantly "rain" down and accumulate on the seafloor
(testa = shell) |
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| most common biogenous sediment that has the consistency of thick mud produced from the tests of organisms such as coccolithophores and foraminifera |
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| single-celled algae that have tests that contribute to calcareous ooze |
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| small organisms, also called forams, that contribute to calcareous ooze |
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| a biogenous sediment composed primarily of tests of diatoms (single-celled algae) and radiolarians (single-celled animals) that prefer cooler surface waters |
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| a form of biogenous sediment derived from the bones, teeth, and scales of fish and other marine organisms |
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| a type of hydrogenous sediment, they are rounded, hard lumps of manganese, iron, and other metals that precipitate in concentric layers around a central object (such as a volcanic pebble or a grain of sand) |
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| a type of hydrogenous sediment, they are formed by precipitation directly from seawater in warm climates |
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| a type of hydrogenous sediment which are usually precipitated as coatings on rocks near black smokers associated with the crest of the mid-ocean ridge |
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| a type of hydrogenous sediment which form where evaporation rates are high and there is restricted open-ocean circulation |
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| unusually compact chemical structures made of water and natural gas |
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| the most common gas hydrate, produced by methane |
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