Pacific Oceanic Bottom Relief

  • The Pacific Ocean is known as the biggest ocean on the earth which occupies 1/3rd part of the entire globe.
  • Pacific Ocean Extension 16000 km in East-West (Asia Coast to America (West Coast), With this, 14800 km in North or South (Bering Strait – Cape Andre (Antarctica).
  • The average depth of the Pacific Ocean is 4500 m.
  • Both the Pacific Ocean’s coast (E&W) is similar to each other. And they are surrounded by the chains of the folded mountain, descent from coast to the abyssal plain.
  • There are approx. 20,000 islands located in the Pacific Ocean.

Island’s group is divided into 3 categories:-

  1. Continental islands: –
    • Aleutian Islands
image 28
  • Islands of British Columbia of Canada (Vancouver Island, Quadra Island, Denman Island, Gabriola Island, North Pender Island, Salt Spring Island, Hornby Island, Galiano Island, Cortes Island, and Saturna Island).
image 29
  • Chilean islands (Chiloé Island, Robinson Crusoe Island, Alejandro Selkirk Island, Isla Salas y Gómez, Isla Grande de Tierra del Fuego, Navarino Island, Santa Clara Island, San Ambrosio, Mocha Island and Desolación Island).
image 35
  1. Island Archs & Festoons:
    • Kuriles
    • Japanese Archipelago (Shikoku, Kyushu, Honshu, Ishigaki, Yakushima Island, Miyako-Jima, Itsukushima, Kuril Islands, Iriomote-Jima, and Yonaguni).
image 30
  • Philippines (Luzon, Boracay, Mindanao, Siargao Island, Palawan, Negros, Leyte, Mactan, Panay, Samar Island).
image 31
  • Indonesian Islands (Sumatra, Bali, Java, Sulawesi, Lombok, Borneo, Flores, New Guinea, Lesser Sunda Islands and Maluku Islands.

3.     South-West group of islands are categorized into three parts.

  • Melanesia
  • Micronesia
  • Polynesia
Johnson Division of Pacific ocean
Northern Pacific1. It’s the very deepest part of the world.
2. Avg. depth is 5000m-6000m.
3. join with Arctic Sea(Through Bering Straits).
Central Pacific1. A huge no, of islands, are found in this region.
2. volcanic prone region.
South-West Pacific1. Many Islands.
2. Marginal Seas.
3. Extensive Continental.
4. shelvesOceanic Trenches.
South-East Pacific1. Most striking relief- East Pacific ridges
2. Absence of marginal seas.

Continental shelf: continental shelfs are meet in the pacific oceans, those are significantly difference, through an extend and characteristics. It’s found a different place and a unique size, that is divided into two parts such as:

Eastern Coast:

1. Australia and Asia– Coast area are very Broad
– Found the extensive shelves  
2. Width Varies b/w– It’s almost defined as 150-1650 km
3. Depth Ranges– Approx. 1000-2000m
4. Several Islands (Specific Shelves characteristics.– Kuriles
– Japanese islands
– Philippines
– Indonesia
– New Zealand etc.
5. Eastern Marginal Seas– Coral Sea
– Java Sea
– Tasmania
– SeaBering
– SeaArafura
– Sea etc.

West Coast:

  • West coast is less extensive continental shelfs, because its nearby to cordilleran cover chains, which are occupied from folded mountains to specific coastal lands.
  • Its avg. width cover is about 80 km.

East Pacific Rise

1. Ridges1.There are not found mid-oceanic ridges such as the Atlantic or the Indian Ocean.
2. Few Scattered Ridges.
3. East Pacific rise/ridge are albatross plateau.
2 . Wides Cover– 1600 km.
3. Extending size from– North New Zealand to the California Coast.
4. Branches1. Eastern branches- its branch connect with the Chilean coast.
2. Other branches- its rise move toward southward in identified east island rise.
5. Other Ridges1. Galapagos ridges- flow east pacific ridges
i. Branches- Cocos and Carnegic ridges.
2. Hawaii Rise- its increase toward north-west to south-east.
i. Depth- 800-970m.
i. Width- 2650km.
3. New Zealand Ridges- depth 300 to 2000m sea level.
i. Cover near Fiji island plateau.
4. Nazca Ridge- off Peru Coast.

6. Cover Zones
1. Clarion Fracture zone.
2. Challenger fracture zone.
3. Molokai fracture zone etc.
image 34

Basin Of Pacific Ocean

There can divide several kinds of Basin of Pacific Ocean such as:

1. Philippine Basin– East area of PhilippineAvg.
– depth: 5000 to 6000m
– Kyushun paian ridge runs in the middle of the basin.
– 5N- south of Japan sea.
2. Fiji Basin– Direction 10s – 32sAvg.
– Depth: 4000m.
– South of Fiji island cover
– Covered: Norkolk island ridge
Karmadec; tonga Trench.
3. Pacific Antarctic Basin– Between the 40s and 60s
– Extends 130w longitude
– South-west of Chilean coast
4. Peru Basin– 5s – 24s longitude
– Avg. depth: 4000m
– Western cover of Peru coast-110w.
5. South Australian Basin– Avg. depth 5000m
– Aka Jeffreys Basin
6. East Australian Basin– Avg. Depth 4500m
– Vary between Australia and New Zealand.
7. South-West Pacific Basin– West karmadec Trench
– 20s – 50s latitude

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