EARTH 106 Study Guide - Quiz Guide: Continental Shelf, Wave Power, Herbaceous Plant

• School: PSU
• Department: Earth Sciences
• Course: EARTH 106
• Professor: B R A L O W E R T I M O T H Y

Document Summary

A sea arch develops when a headland protruding into the ocean causes waves to refract around it. This refraction of waves concentrates their energy in specific locations along the headland, causing particularly rapid erosion if weakness such as faults and fractures are present in the rocks. In other cases the waves may simply begin to erode into rock that is less resistant to erosion than the surrounding rock. Either way the erosion leads to the development of small caves that may eventually meet below a promontory leaving an arch above. The erosion continues and for this reason sea arches are very ephemeral coastal features. When they ultimately collapse the remnants of the arch are called sea stacks. As the volcanic islands subside the reef grows upward and a lagoon develops behind the reef and inside the submerging island. Eventually the island can subside below the water level and a ringlike coral reef structure remains.