The document discusses seafloor spreading and ocean basin topography. It describes how molten rock rises up at mid-ocean ridges due to mantle convection, creating new seafloor that spreads outwards. As seafloor spreads, it pushes the continents apart. The topography of ocean basins is formed, including mid-ocean ridges, rift valleys, seamounts, trenches, and more. Paleomagnetic data provides evidence that supports the theory of seafloor spreading.
3. The Ocean Floor
What do
you think
the ocean
floor would
look like if
we drain all
the
seawater?
4. SEAFLOOR BATHYMETRY
Many topographic
features that exist on the
ocean basin are obtained
after World War I using
the following
technologies:
1 Echo Sounder
2 Side-scan Sonar
3 Satellite altimetry
(Click blue textbox to show image)
is the study of underwater depth of the ocean
floor.
5. OCEAN BASIN
Are the results of tectonic forces and processes
which are formed from volcanic rock that was
released from fissures located at the mid-oceanic
ridges.
6. 1) Pacific Ocean
4) Southern Ocean
3) Indian
Ocean
5) Arctic
Ocean
2) Atlantic
Ocean
Major Ocean Basins
11. The Mid-Atlantic ridge is an underwater mountain range. It is part of the
most extensive chain of mountains that wraps around the globe for more
than 65,000 km.
North American Plate
Mid-Atlantic ridge
12. OCEAN BASIN
TOPOGRAPHIC FEATURES
1
3
5
7
9
1
1
MID-OCEANIC
RIDGE
ABBYSAL PLAINS
OCEAN TRENCHES
VOLCANOES
SUBMARINE
CANYONS
2
CONTINENTAL
SLOPE
4
6
8
1
0
RIFT VALLEY
SEAMOUNT
OCEAN FLOOR
CONTINENTAL RISE
CONTINENTAL
SHELF
Found in the center of mid-oceanic ridge, between 30-50 km wide and
1,000-3,000 m deep.
24. OCEAN BASIN
TOPOGRAPHIC FEATURES
1
3
5
7
9
1
1
MID-OCEANIC
RIDGE
ABBYSAL PLAINS
OCEAN TRENCHES
VOLCANOES
SUBMARINE
CANYONS
2
CONTINENTAL
SLOPE
4
6
8
1
0
RIFT VALLEY
SEAMOUNT
OCEAN FLOOR
CONTINENTAL RISE
CONTINENTAL
SHELF
Can be found at the base of the continental slope. Its depth ranges from
2,000-5,000 me-ters deep.
28. OCEAN BASIN
TOPOGRAPHIC FEATURES
1
3
5
7
9
1
1
MID-OCEANIC
RIDGE
ABBYSAL PLAINS
OCEAN TRENCHES
VOLCANOES
SUBMARINE
CANYONS
2
CONTINENTAL
SLOPE
4
6
8
1
0
RIFT VALLEY
SEAMOUNT
OCEAN FLOOR
CONTINENTAL RISE
CONTINENTAL
SHELF
Is a shallow, gently sloping part of the continental crust with at an average
depth of 130 m that borders the continent.
32. Which of the following statements are
TRUE?
The seafloor is flat or bowl-shaped and the
deepest portion is in the middle.
The seafloor is the same age as the
continents.
The entire seafloor is the same age.
The Earth is expanding; seafloor is created
but never destroyed.
Continents drift through the ocean and
oceanic currents are responsible for
33. All of the following statements are
misconceptions. We’ll discuss them
further…
The seafloor is flat or bowl-shaped and the
deepest portion is in the middle.
The seafloor is the same age as the
continents.
The entire seafloor is the same age.
The Earth is expanding; seafloor is created
but never destroyed.
Continents drift through the ocean and
34. RECALL the Evidences of Continental Drift
Theory
Topographic Evidence, Fossil Correlation,
Rock Formation and Paleoclimatic Evidence
RECALL why many scientists rejected
Alfred Wegener’s Continental Drift?
Wegener could not conceive of an
acceptable mechanism for moving the
continents around.
35. SEAFLOOR SPREADING
DEMONSTRATION
ACTIVITY
After the activity, try answering the following
questions:
1. How sea floor spreading happens?
2. How does the movement of the seafloor affects
the continents?
3. Can seafloor spreading help prove continental
drift theory?
https://youtu.be/V0h8v2w3LGU?list=TLPQMzAwNDIwMjAzbEu4EGHGgA
https://youtu.be/5eka88IOJ-I?list=TLPQMzAwNDIwMjAzbEu4EGHGgA
36. HARRY
HESS
THE THEORY OF
SEAFLOOR
SPREADING
In the 1960’s Harry
Hess, an American
Geophysicist theorized that
the seafloor is a hundred
million years younger than
the continents. He
suggested that not only
were the continents moving
but the seafloor was also
moving. He theorized that
38. Observations/Evidences that lead to the
idea of
SEAFLOOR SPREADING
A. Distribution of seafloor topographic features – distribution
of mid-ocean ridges and depth of the seafloor
B. Sediment thickness – fine layer of sediment covering much of the
seafloor becomes progressively thicker away from mid-ocean ridge axis;
seafloor sediment not as thick as previously thought
C. Composition of oceanic crust – consists primarily of basalt
D. High heat flow along mid-ocean ridge axes – led scientists
to speculate that magma is rising into the crust just below the mid-ocean
ridge axis
E. Distribution of submarine earthquakes – earthquakes do not
occur randomly but define distinct belts (earthquake belts follow trenches,
mid-oceanic ridges, transform faults).
39. HOW DO SEAFLOOR
SPREADS?
Molten material or magma from the Earth's
mantle rises up because of mantle convection at
ocean ridges, causing volcanic and seismic activity,
40.
41. PALEOMAGNETIS
M
A proof that supports seafloor spreading. It
tells how far from the poles rocks were when they
were formed by looking at the angle of their
42. Want to Learn More?
Credits to: M.R. Dela
Peña
Edited by: R.N.
Visit the following websites:
• https://www.slideshare.net/AbbieMahinay
• https://www.youtube.com/watch?v=fcqEnmIPui8
• https://www.youtube.com/watch?v=ZAAuY3l42qc
• https://www.youtube.com/watch?v=-WgzkjPV5Sg