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THE OCEAN FLOOR
Transcript of THE OCEAN FLOOR
After reading and studying Ch. 14, you should be able to:
Concept 1: Explore the oceans and features of our "Blue Planet," including the techniques used to learn more about the ocean floor.
Concept 2: Divide the ocean floor into three topographic units and describe the features associated with both passive and active continental margins.
Concept 3: Describe how each of the three broad categories of seafloor sediments originates and the association between seafloor sediments and climate change.
Concept 4: List several resources obtained from the ocean and the seafloor.
* Nearly 71 percent of Earth’s surface is covered by the global ocean
THE BLUE PLANET
* Oceanography is a science that draws on the methods and knowledge of geology, chemistry, physics, and biology to study all aspects of the world ocean.
Geography of the Oceans
MEMBERS OF GROUP 4:
MILLIVET GAIL MOLINA
KARL JOSEPH NOVIO
RAY JOHN PALAROAN
ANA MAE PEREZ
The world ocean can be divided into four main ocean basins- the Pacific Ocean, the Indian Ocean, the Atlantic Ocean, and the Arctic Ocean.
is the largest and has the greatest depth.
is about half size of the Pacific and not quite as deep.
, largely a southern hemisphere body, is slightly smaller than the Atlantic.
is about 7% ofthe size of the Pacific.
The topography of the ocean floor is as diverse as that of the continents.
is the measurement of ocean depths and the charting of the shape or topography of the ocean floor.
particularly- sonar, satellites, and submersibles- allows scientists to study the ocean floor in a more efficient and precise manner than ever before.
MAPPING THE OCEAN FLOOR
THE TOPOGRAPHY OF THE OCEAN
is an acronym for sound navigation and ranging. It is also referred to as echo
works by transmitting sound waves toward the ocean bottom.
*Satellites are able to measure small differences by bouncing microwaves off the ocean surface.
*Using this new technology, scientists have discovered that the ocean surface is not perfectly flat.
*Differences in the height of the ocean surface are caused by ocean-floor features.
are small underwater crafts used for deep-sea research.
*Today, many submersibles are unmanned and operated remotely by computers. These remotely operated vehicles (ROVs) can remain underwater for long periods.
* The ocean floor regions are the
continental margins, the ocean basin floor, and the mid-ocean ridge.
is the zone of transition between a continent and the adjacent ocean basin floor.
* In the Atlantic Ocean, thick layers of undisturbed sediment cover the continental margin. This region has very little volcanic or earthquake activity.
the Pacific Ocean
, oceanic crust plunges beneath continental crust. This force results in a narrow continental margin that experiences both volcanic activity and earthquakes.
is the gently sloping submerged surface extending from the shoreline.
contain important mineral deposits, large reservoirs of oil and natural gas, and huge sand and gravel deposits.
is the steep gradient that leads to the deep-ocean floor and marks the seaward edge of the continental shelf.
is the 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.
is 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.
is the gently sloping surface at the base of the continental slope.
ocean basin floor
is the area of the deep-ocean floor between the continental margin and the oceanic ridge.
* Trenches form at the sites of plate convergence where one moving plate descends beneath another and plunges back into the mantle.
OCEAN BASIN FLOOR
is a very level area of the deep-ocean floor, usually lying at the foot of the continental rise.
* The sediments that make up abyssal plains are carried there by turbidity currents or are deposited as suspended sediment settles out.
is an isolated volcanic peak that rises at least 1000 meters above the deep-ocean floor, and a guyot is an eroded, submerged seamount.
is found near the center of most ocean basins. It is an interconnected system of underwater mountains that have developed on newly formed ocean crust.
is the process by which plate tectonics produces new oceanic lithosphere at ocean ridges.
* New ocean floor is formed at mid-ocean ridges as magma rises between the diverging plates and cools.
MID- OCEAN RIDGES
form along mid-ocean ridges. These are zones where mineral-rich water, heated by the hot, newly-formed oceanic crust, escapes through cracks in the oceanic crust into surrounding water.
Ocean-floor sediments can be classified according to their origin into three broad categories: terrigenous sediment, biogenous sediment, and hydrogenous sediment.
consist primarily of mineral grains that were eroded from continental rocks and transported to the ocean.
consists of minerals that crystallize directly from ocean water through various chemical reactions.
TYPES OF SEAFLOOR SEDIMENTS
are the main energy products currently being obtained from the ocean floor.
are compact chemical structures made of water and natural gas.
oceanic gas hydrates
are created when bacteria break down organic matter in ocean-floor sediments.
Other major resources from the ocean floor include sand and gravel, evaporative salts, and manganese nodules.
* The offshore
industry is second in economic value only to the petroleum industry.
are hard lumps of manganese and other metals (like cobalt, copper, and iron) that precipitate around a small object.
* When seawater evaporates, the salt increases in concentration until it can no longer remain dissolved. When the concentration becomes high enough, the salts precipitate out of solution and form salt deposits.
* The most economically important salt is halitecommon table salt.