Ocean Floor Presentation

1. Ocean FloorOcean Floor
Reported By:
Capin, Richelle and Gamoso, Ervhic

2. A-The vast world oceanA-The vast world ocean
Earth is often referred to as the blue
planet
•71% of Earth’s surface is represented
by oceans and marginal seas
•Continents and islands comprise the
remaining 29%
Oceans represent 97% of the
Hydrosphere

3. Four main ocean basinsFour main ocean basins
•Pacific Ocean - the largest and
deepest
•Atlantic Ocean – about half the
size of the Pacific Ocean
•Indian Ocean – slightly smaller
than the Atlantic
•Arctic Ocean – about 7 percent
the size of the Pacific

4. Mapping the ocean floorMapping the ocean floor
Bathymetry – measurement of ocean
depths and the shape or topography of
the ocean floor
Echo sounder (also referred to as sonar)
•Invented in the 1920s
•Primary instrument for measuring
depth
•Reflects sound from ocean floor

5. Echo sounder andEcho sounder and
multibeam sonarmultibeam sonar

6. Ocean TopographyOcean Topography
Main Features

7. TopographyTopography
• Is the study of Earth's
surface shape and features.
• Ocean topography is the
study of the ocean floor
and the features of which.

8. Abyssal hillsAbyssal hills
• Hills along the ocean floor. Ranging in height and
diameter, these hills are much larger than the hills
we see on land. 100-2000 meters high and several
KM across.

9. Abyssal plainsAbyssal plains
• Abyssal plains are flat or very gently sloping areas of
the deep ocean basin floor. They generally lie
between the foot of a continental rise and a mid-
oceanic ridge.

10. Continental shelfContinental shelf
• The continental shelf is the extended perimeter of
each continent and associated coastal plain, and
was part of the continent during the glacial periods,
but is undersea during interglacial periods.

11. Continental slopeContinental slope
• The descending slope which connects the sea floor
to the Continental shelf. This is still considered to be
part of the Continent.

12. Continental riseContinental rise
• A gentle slope with a generally smooth
surface, built up by the shedding of
sediments from the continental block, and
located between the continental slope and
the abyssal plain.

13. GuyotGuyot
• A guyot also known as a tablemount, is a flat-
topped seamount. Their flatness is due to erosion by
waves, winds, and atmospheric processes.

14. Mid-Ocean ridgeMid-Ocean ridge
• A mid-ocean ridge is an underwater mountain
range, typically having a valley known as a rift
running along its spine, formed by plate tectonics. It
is usually an oceanic spreading center, which is
responsible for seafloor spreading.

15. TrenchTrench
• The oceanic trenches are hemispheric-scale (one
hemisphere to another) long but narrow
topographic depressions of the sea floor. They are
also the deepest parts of the ocean floor.

16. Mariana TrenchMariana Trench
• Is the deepest part of the
world's oceans, and the
deepest location on the
surface of the Earth's crust. It
has a maximum depth of
about 10,911meters, or 11
kilometers.

17. Sea MountSea Mount
• A seamount is a mountain rising from the ocean
seafloor that does not reach to the water's surface
(sea level), and thus is not an island. These are
typically formed from extinct volcanoes, that rise
abruptly.

18. OceanicOceanic IslandIsland
• One type of oceanic island is found in a
volcanic island arc. These islands arise from
volcanoes where the subduction of one
plate under another is occurring.

19. AtollAtoll
• An atoll is an island of coral that encircles a lagoon
partially or completely.

20. Volcanic fissureVolcanic fissure
• A linear volcanic vent through which lava erupts,
usually without any explosive activity. The vent is
usually a few meters wide and may be many
kilometers long

21. Hydrothermal VentHydrothermal Vent
• A hydrothermal vent is a fissure in a
planet's surface from which
geothermal heated water issues.
Hydrothermal vents are commonly
found near volcanically active
places, areas where tectonic plates
are moving apart, ocean basins,
and hotspots.

22. Passive continentalPassive continental
marginsmargins
•Found along most coastal areas that
surround the Atlantic Ocean
•Not associated with plate
boundaries
• Experience little volcanism and
• Few earthquakes
• Wider sandy beaches

23. Active continentalActive continental
marginsmargins
• Continental slope descends abruptly into
a deep-ocean trench
• Located primarily around the Pacific
Ocean
• Accumulations of deformed sediment
and scraps of ocean crust form
accretionary wedges
• Some subduction zones have little or no
accumulation of sediments (narrow
beaches)

24. Seafloor sedimentsSeafloor sediments
Ocean floor is mantled with sediment
Sources
•Turbidity currents
•Sediment that slowly settles to the
bottom from above
Thickness varies
•Thickest in trenches – accumulations
may approach 10 kilometers

25. Thickness varies
•Pacific Ocean – about 600 meters or
less
•Atlantic Ocean – from 500 to 1000
meters thick
Mud is the most common sediment on
the deep-ocean floor

26. Types of seafloorTypes of seafloor
sedimentssediments
1. Terrigenous sediment
• Material weathered from
continental rocks
• Virtually every part of the ocean
receives some
• Fine particles remain suspended
for a long time
• Oxidation often produces red and
brown colored sediments

27. 2. Biogenous sediments
• Shells and skeletons of marine animals
and plants
• Most common are calcareous oozes
produced from microscopic organisms
that inhabit warm surface waters
• Siliceous oozes composed of skeletons
of diatoms and radiolarians
• Phosphate rich materials derived from
the bones, teeth, and scales of fish and
other marine organisms

28. 3. Hydrogenous sediment
• Minerals that crystallize directly
from seawater
• Most common types include
•Manganese nodules
•Calcium carbonates
•Metal sulfides
•Evaporites

29. Distribution of marineDistribution of marine
sedimentssediments

30. The EndThe End