Exploring the Ocean Floor & Its Features By: Samantha Hillistad Darlin Garcia Ilse Garcia

Table of Contents Sediments Sonar Submersibles Divisions Mid-Ocean Ridges Trenches Abyssal Plains Seamounts

Sediments The Ocean floor is flat because of sediments constantly building up, at an even rate. 3 types: 1.) Siliceous oozes 2.) Calcareous oozes 3.) red clay These sediments accumulate very slowly, just a few centimeters per millennium.

Sonar Sonar is an acronym for sound navigation ranging. The ocean bottom is mapped out using sound waves. The pulse of sound spreads out through the water and is reflected back again by objects in the water; e.g. ocean bottom, a fish, or a submarine.

Submersibles Submersibles are used for studying and observing the deepest depths in the ocean. Two Basic Types of submersibles A) The remotely operated vehicle (ROV) is controlled by the surface by a tether, or cable. B) The untethered ROV, more generally called an autonomous underwater vehicle (AUV) eliminates the cable and carries its own power.

Divisions

Mid-Ocean Ridges They are a continuous series of underwater mountain ranges. Formed by a divergent plate boundary. Only in a few places do mid-ocean ridges rise above sea level.

Trenches These long, narrow depressions are located along the Pacific Ring of Fire. The Mariana Trench is the deepest part of the ocean. a) It is almost 7 mi (11 km) below sea level. b) Its deepest part is known as the Challenger Deep. c) Formed by a convergent plate boundary.

Abyssal Plains Approximately 40% of the planet’s ocean floor is covered by these features. Depths are over 6,500ft (1,980 m) below sea level. Also known as the continental shelf. Organisms living here have specialized body structures designed to handle the great pressure.

Seamounts Underwater volcanic mountains. Rise from the seafloor and do not break the water’s surface. If tall enough to break the sea surface, they are called oceanic islands. (Hawaii) Underwater volcanic mountains. Might stay volcanically active for 2-3 million years, while on a hot spot. Above 1,000m = seamount Between 500-1,000m= knoll Below 500m=hill