Consider the following statements:

I. In general, the terrigenous deposits are derived from the land and are mainly deposited on the continental shelves.

II. From the shore onwards, there is a gradual increase in the coarseness of the terrigenous deposits.

III. The muds, the finest materials, are the terrigenous deposits.

IV. The colouring of the muds depends upon their chemical content.

Which of the above statements are correct?

Key Points

• Terrigenous deposits are derived from the land (statement I).
• The muds, which are the finest materials, are considered terrigenous deposits (statement III).
• The coloring of the muds is dependent on their chemical content (statement IV).
• However, statement II is incorrect because there is generally a decrease in the coarseness of terrigenous deposits from the shore onwards.

Additional Information

• Terrigenous Deposits:
  • Terrigenous deposits are sediments derived from the erosion of rocks on land.
  • These materials are transported to the ocean primarily by rivers, wind, and glaciers.
  • Examples include sand, silt, and clay.
• Continental Shelves:
  • The continental shelf is the extended perimeter of each continent, which is submerged under relatively shallow seas and gulfs.
  • It is typically rich in marine life and resources.
• Particle Size Distribution:
  • As sediments move away from the shore, there is a general trend of decreasing particle size.
  • Coarser materials like sand are deposited closer to the shore, while finer materials like silt and clay are carried farther out.
• Chemical Content of Muds:
  • The color of the muds can indicate their chemical composition. For example, red and brown muds often indicate the presence of iron oxides.
  • Black muds may indicate the presence of organic material or sulfide minerals.