Download Ocean Topography - Lithosphere PowerPoint

OCEAN TOPOGRAPHY
FEATURES OF THE OCEAN FLOOR
What do you think the
ocean floor looks like?
It actually looks like this…
It has the same mountains, valleys, plains,
trenches, and pits that we find on land.
Features of the Ocean Floor
• Continental shelf: surrounds the continent as
a shallow extension of continental crust
extending out to the continental slope.
Features of the Ocean Floor
• Continental slope: steep drop-off at the end
of the continental shelf that connects the
continental crust to the oceanic crust.
Because variations in ocean depths are
often noticeable, that means the divisions
of the lithosphere are commonly seen.
Continental Shelf
Continental Slope
Features of the Ocean Floor
• Continental rise: area of accumulated
sediments that marks the absolute boundary
between the continental crust and the
oceanic crust.
Features of the Ocean Floor
• Abyssal plain: the deepest part of the ocean.
Features of the Ocean Crust
Abyssal plains are the flattest areas on earth
Features of the Ocean Crust
• Seamounts: isolated
volcanic mountains
which erupt under
the ocean. Large
ones are islands.
• Guyots: are extinct
volcanoes with
eroded flat tops.
Features of the Ocean Crust
• Ocean ridges: are long mountain ranges
formed when magma seeps or erupts
between pieces of the Earth’s crust (tectonic
plates).
Features of the Ocean Crust
The ocean ridges form a mountain chain that
extends 40,000 miles through all the oceans.
Features of the Ocean Crust
• Trenches: are the deepest part of the ocean.
Trenches form where one tectonic plate
is forced under another plate.
Earth’s HIGHEST mountains,
DEEPEST valleys,
and FLATTEST plains
are all on the ocean floor!
The highest mountain on Earth is
Mauna Kea, Hawaii, a seamount.
The average depth of the ocean is
around 12,200 feet or 3,730m.
The Trieste
and the
Mariana
Trench
Exploration
The Mariana
Trench
In 1960, the US Navy
sent down a small
submersible (minisub) that sat on the
bottom at 35,838 ft.
(10,923 m.)
The sailors had 7
miles of water over
their heads!
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