Island Formations & Dissolutions

Written by: Caroline Kim

October 1, 2022

Simply put, Islands are a small chunk of land surrounded by water. Islands have become a major tourist location, and are often famous for their beautiful environment, climate, and culture. One you’ve probably heard of is the Hawaiian Islands in the U.S., known for their beaches, volcanoes, and historical significance. However, Islands serve as more than just vacation destinations for humans: they are homes to rare species, act as conservation frontiers, are resting stations, and facilitate coral reefs (Kaiser). Their formations, disappearance, and functions can all be found here today.

There are 6 major types of islands to take note of: continental, tidal, barrier, oceanic, coral, and artificial (Island). The idea behind continental islands is that they are pieces of a continent that drifted off over time, an example being Greenland; another continental formation is caused by changes in sea level or weathering, causing some mainlands to become islands (Island). In a tidal formation, the land connecting the smaller piece to the mainland is not entirely diminished, but rather just underwater; this can be credited to high tide (Island). Barrier Islands are strips of sediment, coral, silt, or gravel. They often act as buffers against storms and are separated from shores by lagoons (Island). These can form from events such as ice melt, which cause global rise in sea levels. Oceanic/Volcanic islands are formed from the buildup of lava from erupted volcanoes; the ones that break the surface of the water are known as islands, and the ones shy of the surface are known as seamounts (Island). As indicated by its name, coral islands consist of coral reefs (calcium carbonate skeletons) that have accumulated enough above the surface to become an individual island (Island). In fact, the Bahamas and Caribbean Islands are coral islands. For agricultural and developmental purposes, artificial islands are made by man.

However, islands also disappear in unique ways: liquefaction, sinkholes, and concrete seawalls. Liquefaction is just what it sounds like: loose water filled sediments loose their structure from shaking (What is Liquefaction). Sinkholes form when the sediment/ground (limestone, carbonate rock, salt beds, etc.) is dissolved from groundwater, diminishing the ground below it (Water Science School). Climate change contributes to the disappearing of islands and has proven time and time again to be a concern for the earth; climate change is the source of many ecological ramifications, and new solutions such as sea level regulators or water storage systems would be beneficial towards neutralizing the effects.

Sources:

Kaiser, Sara. “5 Reasons Islands Are Important for the Planet.” Island Conservation, 23 May 2017, https://www.islandconservation.org/five-reasons-islands-are-important-for-the-planet/#:~:text=Islands%20are%20key%20foundations%20for,as%20the%20Island%20Mass%20Effect.

“Island.” Edited by Jeannie Evers, National Geographic Society, https://education.nationalgeographic.org/resource/island.

Bastos, Jorge. “What Is Hawaii Famous for? 14 Things Fully Explained.” Travel Drafts, 6 Aug. 2022, https://www.traveldrafts.com/what-is-hawaii-famous-for/.

“What Is Liquefaction?” What Is Liquefaction? | U.S. Geological Survey, https://www.usgs.gov/faqs/what-liquefaction#:~:text=Liquefaction%20takes%20place%20when%20loosely,cause%20major%20damage%20during%20earthquakes.

Water Science School. “Sinkholes Completed.” Sinkholes | U.S. Geological Survey, https://www.usgs.gov/special-topics/water-science-school/science/sinkholes.