NCERT Notes: Oceanic Landforms – Minor Relief Features [Geography Notes For UPSC] l


This article talks about the Minor Relief of the Ocean Floors. These notes will also be useful for other competitive exams like banking PO, SSC, state civil services exams and so on.

What are Ocean relief?

Ocean relief is largely due to tectonic, volcanic, erosional and depositional processes and their interactions. Ocean relief features are divided into major and minor relief features. The ocean floors can be divided into four major divisions.

Here aspirants will get detailed information on the Minor Ocean relief features. The NCERT notes on important topics are helpful to prepare for the UPSC civil services exam.

Minor Relief of the Ocean floor (UPSC Notes):- Download PDF Here

Aspirants preparing for the IAS Exam can go through the given link to get all the relevant details on the examination.

Minor Relief of the Oceans

Some minor relief features in the ocean floors like-

  • Mid-Oceanic Ridges
  • Seamounts
  • Guyots
  • Trenches
  • Canyons
  • Ridges
  • Hills
  • Sleeps
  • Fracture Zone
  • Atolls
  • Island Arcs
  • Coral reefs
  • Sea Scarps
  • Submerged Volcanoes

Mid Ocean Ridges

  • A mid-oceanic ridge is an underwater mountain range, formed by plate tectonics.
  • It is composed of two chains of mountains divided by a large depression.
  • The mountain ranges can have peaks as high as 2,500 m and some even reach above the ocean’s surface.
  • Examples for Mid-oceanic ridges:
    • Mid-Atlantic Ridge, Atlantic Ocean
    • East Pacific Rise
    • Pacific-Antarctic Ridge

Candidates can go through the following links relevant to their UPSC preparation-


  • Seamounts are mountains with pointed peaks, mounting from the seafloor, and that do not reach the surface of the ocean.
  • They are volcanic in origin.
  • Seamounts can be 3,000-4,500 m tall.
  • An extension of the Hawaiian Islands in the Pacific Ocean which is known as The Emperor seamount is an example of the seamount.

Submarine Canyons

  • Submarine Canyons are a kind of narrow steep-sided valleys.
  • It originates either within continental slopes or on a continental shelf.
  • Congo Canyon is regarded as the largest river canyon.
  • The Hudson Canyon is the best-known submarine canyon in the world.
  • The largest submarine canyon in the world is Zhemchug Canyon.


  • It is a flat topped seamount.
  • It is also known as a table mount.
  • They show evidence of slow subsidence through stages to become flat-topped submerged mountains.
  • It is expected that more than 10,000 guyots and seamounts occur in the Pacific Ocean only.


  • It is a ring-shaped coral reef containing a coral rim that encompasses a lagoon incompletely or completely.
  • These are low islands found in the tropical oceans.
  • It may be a part of the sea (lagoon), or occasionally form encircling a body of brackish, fresh, or highly saline water.


  • A reef is a predominantly organic deposit made by living or dead organisms that form a mound or rocky elevation like a ridge.
  • Coral reefs are a characteristic feature of the Pacific Ocean where they are associated with seamounts and guyots.
  • The largest reef in the world is found off the Queensland coast of Australia.
  • Since the reefs may extend above the surface, they are generally dangerous for navigation.

Minor Relief of the Ocean floor (UPSC Notes):- Download PDF Here

Check BYJU’S Free IAS Preparation for more NCERT Geography notes and news on UPSC Civil Services IAS Exam

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The above details would help candidates prepare for UPSC 2023.

Aspirants can find complete information about upcoming Government Exams through the linked article. UPSC exam-related preparation materials will be found through the links given below.

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