Where are deltas found?

Deltas can occur in lakes and inland seas as well as in the ocean, but they are most important in the open ocean (Boggs). Deltas are particularly common in the modern ocean owing to post-Pleistocene sea-level rise coupled with high sediment loads carried by many rivers. They often contain extensive wetlands, whose high biological productivity makes them vital nursery grounds for fisheries. Huge amounts of coal, oil, and natural gas are found in subsurface ancient deltaic deposits. Deltas seldom form on active, subductingcontinental margins because there is no stable shallow shelf on which sediments can accumulate. Twenty-five (25) of the world’s largest deltas are found on passive margins of continents. They are categorized according to features within the delta plain and by energies acting on the delta (tide, wave, and fluvial). The size of a delta is dependent on the size of the drainage basin, the elevation of the land, and climate.