World's major ocean floors can be studied by their submarine reliefs and bathysphere. - Horizontal distribution of Seawater Temperature (latitudinally)

6. Atlantic Ocean Floor
- S-shaped ridge in the middle of the
ocean.
- Atlantic ocean occupies 1/6th
part of
total earth surface.
- Continental Shelf is narrow along
S.Atlantic , broad along USA, UK,
Argentina.
other ridges are :-
1.Dolphine ridge / rise- N.Atlantic
2.Challenger ridge / rise – S.Atlantic
3.Walvis ridge / rise
4.Rio Grande rise/ ridge
Ocean Basins / Abyssal Plains :-
a.Labrador basin
b.NW Atlantic – largest in extent
c.Cape Verde basin
d.Brazil basin
e.Argentina
f.Agulas basin
1
2 3
4
b
c
a
d
e f
iii
ii
i

7. Ocean Deeps/ Trenches:-
i. Peuto Rico deep (8660 m)
ii. South Sandwich (7881 m)
iii. Romanche Trench (7254 m) –
cuts and divides dalphin and
challenger rise.
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• small seas – Carribean sea,
North sea, Mediterranean sea,
Hudson bay, English
channel,etc.
• --------------------------------------------
-----
• Lack of islands
• New Folkland (famous for foggy
weather , fog is formed due to
mixing of Brazilian warm and
Antarctic cold ocean current)
and British Isles
• Carribean / West Indies islands.

8. E
a
s
t
P
a
c
i
f
i
c
r
i
d
g
e
2
3
4
a
b
e
f

9. other ridges :-
- Very few ridges/ rise
1. East Pacific ridge
2. Macquaries ridge
3.Hawaiin rise
4.Aleutian rise
Ocean Basins / Abyssal Plains along
with plateaus:-
a.Aleutian basin/ plain
b.Philippine
c.Fiji
d.W and E Caroline abyssal plain
e.Tasmanian basin
f.SW Pacific basin
Ocean Deeps/ Trenches:-
Total 32 deeps alone in pacific
i.Mariana/ Nero Trench(11,030m)
ii.Aleutian
iii.Kurile and Japan Trench
iv.Tonga- Kermadac
v.Peru- Chile Trench
1
2
4
3

10. PACIFIC OCEAN FLOOR
• Cover 33% of earth’s total surface..
• Roughly triangular in shape
• Bordered by – N. S. America towards east
- Eurasia and Australia towards west
• length :- 14,900 km and width :- 16,000 km
• Average depth – ~5000m
•Its divided into 4 parts :-
1.N Pacific - deepest part of the world
2.Central P. - famous for corals and volcanic islands – max in world.
3.SW P. - Trenches are max. Shelves are broadest- fishing ground
4.SE P. - Submarine ridges and plateau
Continental Shelf :- Easter margin is narrow due to Rockies – Andies
Western margin is broad
average width ~ 160-1600km
on these shelves lies islands and seas.

11. INDIAN OCEAN
- Warm ocean covering 20%
Of total earth’s surface.
-The Indian Ocean is
bounded on the north by
Asia; on the west by Africa;
on the east by Australia; and
on the south by Antarctica.
Shape is compact, bold and
with regular.
- Average depth – 4000m
-Continental Shelf :-
-Width is varying and not
specific. Average- 96 km
- Generally narrow along
Sumatra and Australia ,
-but wider near Bay of
Bengal, African coast.
- Narrowest along Antarctica

12. C
A
F
B
E
D
1
2
3
4
5
6
7
8
9
T
T
9a

13. INDIAN OCEAN
Ridges and basins :-
A. It has continuous Central ridge called ‘Arabian- Indian ridge’ – bifurcated into many
ridges separating Indian Sub-continent, Africa, Antarctica .e.g.
B.East –Indian/ Ninety East ridge,
C.Madagascar ridge,
D.Socorta-Chagos ridge,
E.Kerguelen- Gaussberg ridge – connected to Antarctica continent.
F.South East Indian Ridge
Ocean basin / Abyssal plain :-
Central Ridge divides abyssal plains into various basins (~ 4000 – 6000 m) almost
50% of Indian Ocean is covered by plains.
1.Oman basin
2.Arabian extends as-
3.Socorta - Chagos ridge
4.Somali basin
5.Mauritius / Madagascar plain
6.Natal plain
7.Kerguelen plain
8.Anadaman basin
9.Cocos plain/ basin 9a. Ceylon plain
Ocean Deeps/ Trenches :- almost absent
Sunda Trench (450 m), Nicobar Trench

18. PROCESSES OF HEATING
Major Minor
1. Absorption of insolation Transformation of kinetic energy
into heat energy.
2. Conventional current formation
due to internal heat of earth
heating of water due to Chemical
processes
Condensation of water vapour

19. FACTORS AFFECTING THE DISTRIBUTION OF
SEA WATER TEMPERTURE
1.Intensity and daily duration of solar energy.
2.The depletion of this energy in the atmosphere by – reflection,
scattering, absorption.
3.Heat balance/ budget
4.Latitudes ( seasonal variation, insolation, land –sea distribution)
5.Ocean currents
6.Prevailing winds ( landlocked seas get highly affected)
7.Local weather (land –sea breezes, vegetation cover, land use)
8.Seepage of nuclear power plants (anthropogenic effect)

20. Horizontal Distribution of Sea-water Temperature (latitudial)
26.80
C
25.6
23.9
12.9
20.3
8.9
4.3
-1.4
The surface water temperature varies
according to angle of
Sunrays & latitudes.
avrg. Temp. = 26.80
C
may increase upto
300
C in summer.
Prevailing winds
are responsible
to drive the
water-warm
or cold.
thus ocean currents/ drifts
brings warm currents
from equator , cold currents
from poles.
Local weather also affects
the distribution and properties
of ocean currents.
--- Thus, Water surface temp. decreases from equator towards poles