Sea stacks form as a result of the constant crashing of oceanic waves against a cliff. Erosion creates sea caves out of the cliff, and arches develop over time. As the rock is worn down further, the arches become sea stacks.
Sea caves form when the strong energy of the waves creates cracks in the rock surface. Over time, the cracks become larger, eventually forming blowholes. The waves continue to erode the blowholes, and they become sea caves. If the cliff juts out into the ocean, the waves can break down both sides of the rock, turning sea caves into arches. If one half of the arch is softer than the other, the softer side breaks down faster, leaving one side to become a sea stack.
A sea stack located off the coast of Oregon called Jump-Off Joe was made of sandstone, eroding over the course of the 20th century. Other sea stacks in Bandon Beach, Ore. are composed of sandstone or chert, rocks that are relatively hard when measured on the Mohs scale. Waves erode rocks through corrosion and hydraulic action, but the waves can only quickly break down rock that is soft. The inner part of the headland or cliff that is harder takes a longer time to break down into sea caves or arches. The process continues until the waves push the coastal landscape further inland.Learn More
When a volcano surfaces just above sea level, erosion from waves can create a plateau called a guyot, that eventually sinks below sea level. Guyots sinks as a result of both erosion and the tectonic plates that the ocean floor rests on slowly moving apart.Full Answer >
Streams form when downhill running water creates a channel capable of carrying water. Most streams begin as temporary rivulets that only have water after a rainfall.Full Answer >
Uluru began to form over 550 million years ago when sand, eroding from the Peterman Ranges, built up into thick deposits. Some 50 million years later, these deposits were compressed into sandstone by the weight of a sea that eventually disappeared. Within another 100 million years, geological events caused the sandstone to tilt almost 90 degrees, resulting in Uluru.Full Answer >
A strait is either formed by tectonic shifts or land that has subsided or been eroded. If a strait is created by people rather than geological forces, it is generally referred to as a canal.Full Answer >