Describe the basic bathymetric characteristics of mid-ocean ridges, deep-ocean trenches, and seamount chains. (C)

Begin by defining the three features: 1. Mid-ocean ridges: These are long, underwater mountain ranges that run through the middle of ocean basins. 2. Deep-ocean trenches: These are narrow and deep depressions in the ocean floor, usually found near the edges of oceanic plates. 3. Seamount chains: These are isolated underwater mountains or chains of mountains that are generally of volcanic origin and are not part of mid-ocean ridges or continental shelves.

Mid-ocean ridges have the following characteristics: 1. Shape: These ridges are elongated and have a central rift valley. They can extend over thousands of kilometers. 2. Depth: Mid-ocean ridges rise 2 to 3 kilometers above the ocean floor, and their summits usually lie 2.5 kilometers below the ocean surface. 3. Spreading centers: Being tectonic plate boundaries, mid-ocean ridges are characterized by seafloor spreading, where two adjacent plates are moving apart from each other. This results in the formation of new oceanic crust.

Deep-ocean trenches have the following characteristics: 1. Shape: These trenches are generally narrow and elongated, extending along the edges of one or more oceanic plates. 2. Depth: They are the deepest parts of the ocean, with depths ranging from 6 to more than 11 kilometers below the ocean surface. The Mariana Trench, for example, reaches a depth of over 11 kilometers (11,034 meters at its deepest point, the Challenger Deep). 3. Subduction zones: Deep-ocean trenches are typically located near subduction zones, where an oceanic plate is being pushed underneath another plate (either oceanic or continental).

Seamount chains have the following characteristics: 1. Shape: These underwater mountains can be conical, domal, or elongated in shape, and sometimes have flat tops (called guyots) due to erosion by waves and currents. 2. Depth: Seamounts usually rise between 1 to 2.5 kilometers above the ocean floor, and their summits can be located in depths ranging from a few meters to several thousand meters below the ocean surface. 3. Volcanic origin: Seamount chains are generally formed by volcanic activity and can be found in various settings, such as on oceanic plates away from plate boundaries or near volcanic hotspots. In conclusion, mid-ocean ridges, deep-ocean trenches, and seamount chains each have distinct bathymetric characteristics related to their formation processes and locations. By recognizing these characteristics, you can better understand the processes that shape our ocean floor.