Along the edge of each continent is a sloping, subsurface earthen mass extending from the continent’s terrestrial base. This area, known as the continental shelf, provides an environment hospitable to fish and plant life. The area is also home to energy sources like natural gas and oil. Continental shelves are mapped by oceanographers who determine their depth and distance.
Oceanographers have found that the continental shelf surrounding North America is shallow. The depth reaches, at its deepest points, 650 feet. The distance the shelf extends from the shoreline ranges from 12 to 250 miles. Within these narrow, shallow waters divers find schools of tuna, cod and mackerel and other fish. Plant life is abundant and encourages the fish population. Human societies depend on the food provided by the aquatic life within the continental shelf region.
Continental shelf regions form after tectonic plates shift with enough force to break up continents. Tectonic plates and continent breaks are rarely smooth and clean. Detritus from the break crumbles into the ocean floor. The sediment piles up creating a slope which then leads to the continental shelf and the shoreline. Sediment is shaped further by volcanic activity, turgid water movement and earthquakes. The continental shelf is an ever-changing geographical region. Oceanographers map changes as a way to aid energy exploration in the area and to assess wildlife conditions.
Modern societies drill along and into the continental shelf for oil and natural gas. Due to the wildlife in the area and the importance of the fishing industry to local economies care must be taken when drilling into the continental shelf.
Where the continental shelf ends, you will find an area called the continental slope. This declining area leads into the ocean proper. The entire geographcial area – the continental shelf, the continental slope and the continental rise are referred to as the continental margin. Only the continental shelf and continental slope are considered part of the continent.
The continental shelf provides countries with a demarcation for their coastal waters but the legal definition is often different from the geological definition. International law dictates that a continent’s external continental shelf is measured at 200 nautical miles from the shoreline. This determination allows continents and countries with narrow or non-existent continental shelves to have control over their coastline.
Whether a naturally occurring phenomenon or a political necessity, the continental shelf is an important region. The fish industry, wildlife and natural resources are some of the valuable assets in this region.