Deep Sea Topography Notes

Seamount

  • An underwater mountain formed by volcanic activity.
  • They rise from the ocean floor but do not reach the surface.

Continental Shelf

  • The gently sloping underwater edge of a continent.
  • Rich in marine life and resources.

Continental Rise

  • The area of the ocean floor at the base of the continental slope.
  • Diagram shows its location relative to the continental shelf, slope, and deep ocean floor.

Continental Slope

  • The steep slope between the continental shelf and the deep ocean floor.
  • Diagram shows its location relative to the continental shelf, rise, and deep ocean floor.

Submarine Canyon

  • A steep-sided valley cut into the seabed.
  • Often formed by river erosion or tectonic activity.
  • Located on the continental slope/shelf

Oceanic Trench

  • A deep, narrow depression in the ocean floor.
  • Often caused by tectonic subduction.

Abyssal Hill

  • Small hills on the ocean floor, found in the abyssal plains.
  • Formed by tectonic activity.

Guyot

  • A flat-topped underwater mountain.
  • Usually a former seamount that has eroded over time.

Rift

  • A crack or fault in the Earth’s crust where tectonic plates are moving apart.
  • Often leading to volcanic activity.
  • Example: Mid-Ocean Ridge

Mid-Ocean Ridge

  • An underwater mountain range formed by tectonic activity.
  • New oceanic crust is created here.

Island

  • A piece of land surrounded by water.
  • Often formed by volcanic activity or rising sea levels.

Benthic Zone

  • The ocean floor zone where organisms live.
  • Includes the surface sediments and subsoil.
  • Depths: Epipelagic Zone (200m), Mesopelagic Zone (1000m), Bathypelagic Zone (4000m), Abyssopelagic Zone (6000m), Hadopelagic Zone (10000m)

Pelagic Zone

  • The open ocean, far from the shore.
  • Most of the ocean's life exists here.

Sediment

  • Particles of organic or inorganic matter that settle at the bottom of the ocean.

Deep-Ocean Basin

  • Large, flat areas of the ocean floor

Volcanoes

  • Geological formations where molten rock, gas, and ash escape from beneath the Earth’s surface.
  • Often found along tectonic plate boundaries.

Mariana Trench

  • The deepest part of the world's oceans.
  • Located in the western Pacific Ocean.
  • Depth of more than 11KM11 \text{KM}.

Challenger Deep

  • The deepest point of the Mariana Trench.
  • Approximately 36,000 feet below sea level.
  • 11,035meters below sea level11,035 \text{meters below sea level}.

Oceanic Crust

  • The thin, dense layer of the Earth's crust that forms the ocean floor.
  • Mainly composed of basalt.

Hydrothermal Vent

  • A fissure in the Earth's crust, often on the ocean floor, from which hot, mineral-rich water escapes.
  • Related to chemosynthesis.

Oceanic Pressure

  • The weight of the water above that increases with depth.
  • Reaching extreme levels in the deep ocean.

Topography

  • The detailed physical features of the ocean floor, including mountains, valleys, and plains.