oceanography Oceanography (), also known as oceanology and ocean science, is the scientific study of the oceans. It is an Earth science, which covers a wide range of topics, including ecosystem dynamics; ocean currents, waves, and geophysical fluid dynamic ...

, terrigenous sediments are those derived from the erosion of

rocks In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its chemical composition, and the way in which it is formed. Rocks form the Earth's ...

on land; that is, they are derived from ''terrestrial'' (as opposed to marine) environments. Consisting of

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

mud A MUD (; originally multi-user dungeon, with later variants multi-user dimension and multi-user domain) is a Multiplayer video game, multiplayer Time-keeping systems in games#Real-time, real-time virtual world, usually Text-based game, text-bas ...

, and

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...

carried to sea by

river A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of wate ...

s, their composition is usually related to their source rocks; deposition of these sediments is largely limited to the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

. Sources of terrigenous sediments include volcanoes, weathering of rocks, wind-blown dust, grinding by glaciers, and sediment carried by rivers or icebergs. Terrigenous sediments are responsible for a significant amount of the salt in today's oceans. Over time rivers continue to carry minerals to the ocean but when water evaporates, it leaves the minerals behind. Since chlorine and sodium are not consumed by biological processes, these two elements constitute the greatest portion of dissolved minerals.

Quantity

Some 1.35 billion tons, or 8% of global river-borne sediment (16.5-17 billion tons globally), is transported by

Ganges The Ganges ( ) (in India: Ganga ( ); in Bangladesh: Padma ( )). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international river to which India, Bangladesh, Nepal and China are the riparian states." is ...

Brahmaputra The Brahmaputra is a trans-boundary river which flows through Tibet, northeast India, and Bangladesh. It is also known as the Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, Luit in Assamese, and Jamuna River in Bangla. It ...

river system annually according t
decades old studies
it is unquantified how much variance year to year as well as the impact modern humans have on this amount by holding back sediment in dams, counteracted with increased erosionary development patterns. Wind born sediment also transports billions of tons annually, most prominent in

Saharan dust Saharan dust is an aeolian mineral dust from the Sahara desert, the largest hot desert in the world. The desert spans just over 9 million square kilometers, from the Atlantic Ocean to the Red Sea, from the Mediterranean sea to the Niger River v ...

, but thought to be substantially less than rivers; again variance of year to year and human impacts of land use remain unquantified on this data. It is well known terrain influences climate conditions, and erosive processes slowly but surely modify terrain along with tectonic causes, but all encompassing studies have been lacking on a global scale to understand how these ''shape of land and sea'' factors fit in with both human induced

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

and natural geoastrological climate variability.

References

Cited

* Sedimentary rocks Sedimentology Marine geology Oceanography {{Ocean-stub

Quantity

See also

References

Cited