Origin Of Ocean Basins

Rationale: Abyssal plains are extremely flat and featureless areas that cover nearly 40% to 41% of the total ocean floor, making them the largest single relief feature in ocean basins.

Rationale: Harry Hess proposed the concept of seafloor spreading in 1960, suggesting that oceans grow from their mid-ocean ridges due to convective currents.

Rationale: Guyots are submerged flat-topped seamounts that were eroded by wave action at sea level before being downfaulted or subsiding to great depths.

Rationale: The continental shelf generally slopes gently from the coast and ends abruptly at the shelf break, which typically lies at an average depth of 130 to 200 meters.

Rationale: The Sunda Trench (also known as the Java Trench) is the deepest point and primary trench located in the eastern Indian Ocean.

Rationale: Vine, Matthews, and Morley linked geomagnetic reversals to the symmetrical magnetic striping observed across mid-ocean ridges, proving seafloor spreading.

Rationale: Eduard Suess postulated that as the Earth cooled, the contraction of the crust caused parts of the lighter Sial crust to sink, forming depressions that filled with water to become ocean basins.

Rationale: Submarine canyons are steep, V-shaped valleys primarily carved into the continental shelf and slope by turbidity currents and underwater avalanches.

Rationale: The Atlantic Ocean exhibits an 'S' shape, reflecting the jigsaw-fit alignment of the Americas against Europe and Africa, supporting continental drift.

Rationale: The Mariana Trench, containing the Challenger Deep, is situated in the western Pacific Ocean along a convergent plate boundary.

Rationale: The continental rise acts as an apron of thick sediments deposited at the base of the continental slope, merging smoothly into the abyssal plain.

Rationale: Wegener invoked centrifugal force (pole-fleeing force) and gravitational tidal forces of the sun and moon to explain continental movement.

Rationale: Mid-ocean ridges represent divergent or constructive plate boundaries where basaltic magma wells up from the mantle to form new oceanic crust.

Rationale: Arthur Holmes proposed the mantle convection current theory in 1928-1929, providing the thermal engine that later inspired plate tectonics and seafloor spreading.

Rationale: According to Darwin's subsidence theory, coral atolls form as fringing reefs grow upward around subsiding volcanic islands, eventually leaving a central lagoon.

Rationale: Pelagic deposits, such as red clay and various oozes, accumulate slowly in the deep abyssal regions far away from landmasses.

Rationale: The standard macro-relief divisions of ocean basins include continental margins (shelf, slope, rise), deep-ocean basins (abyssal plains, trenches, seamounts), and mid-ocean ridges. Epicontinental basin is not a standard macro-relief category.

Rationale: Continental shelves are widest off low-relief, stable continental plains (e.g., Arctic coasts of Siberia or off northeastern North America) and narrowest near active subduction zones.