Exam 18: The Sea Floor

The continental shelves of the world are typically covered by relatively young sediments derived from ___________.

_____ parallel the shore, but are separated from it by wide, deep lagoons.

Most seamounts are active volcanoes.

Water depth increases over a continental shelf to the outer edge depth of _____ to ____ meters.

The crests of mid-oceanic ridges are associated with ____.

The continental shelf is part of the ____.

__________ is the name applied to hot springs on the seafloor where 350 degree Celsius metal-rich solutions are discharged into the cold waters of the ocean.

_____ are V-shaped valleys that run across continental shelves and down continental slopes.

Turbidity currents flow down the continental slope until they come to rest on ___.

Shallow focus earthquakes on the sea floor are associated with ___.

The ocean became salty as water picked up chlorine from volcanic gases and sodium and magnesium from weathering of minerals at the Earth's surface.

Ocean water originated mainly from degassing of the Earth's interior.

A(n) _____ continental margin usually lacks a continental rise and an abyssal plain and is associated with convergent plate boundaries.

Oceans cover _____ percent of the Earth's surface.

Passive margins are found on the edges of most of the landmasses bordering the Pacific Ocean.

Most seamounts are ______.

_____ are rounded masses of rock that form when molten lava erupts into cold water.

Many guyots and seamounts are aligned in chains (for example the Hawaiian Islands and Emperor seamounts) that form major _____.

A rift valley runs down the crest of most mid-oceanic ridges.

Geologists' ideas about the composition of ocean crust are greatly influenced by the study of ____.