Free Sea Floor Sediments Essay Sample

Introduction

The sea floor is comprised of different substrates coming from different origins such as living organisms, land, sea, and atmosphere. These continuous supplies of particles are known as sediments that have accumulated in the sea floor (Sverdrup et al., 2005). With the various origins of sea floor sediments, it can be classified depending on several factors which also encompass its distribution and locations in the ocean.

Classification of Sea Floor Sediments and its Distribution

Oceanographers classify sea floor sediments based on its particle size, source, and location. Under the particle size category, sediments can be classified based on its descriptive names which are gravel, sand and mud. Gravel, with diameter size ranging from 2 to greater than 256 mm, is inclusive of boulder, cobble, pebble and granule. Sand has a diameter range of 0.0625-2 mm and can be classified to very coarse, coarse, medium and fine. Muds, composed of silt and clay, have diameter size of less than 0.0625 mm (Sverdrup et al., 2005).
Sea floor sediments can also be classified as neritic or pelagic depending on its location. The term neritic refers to ‘of the coast’ sediments while pelagic refers to ‘of the sea’ sediments (Sverdrup et al., 2005). Neritic sediments are located near continental margins and islands. These particles usually originated from rocks which have eroded from the land and transported via river systems. On the other, pelagic sediments are fine-grained particles which eventually settle on the deep-sea floor. The thickness of these sediments is an indicator of the age of the sea which it covers. Additionally, the area between the shelf break and rise is a combination of the neritic and pelagic deposits. The distribution pattern of these sediments is affected by factors such as the rate of supply and the proximity to the source. Sediment deposits rate have a wide range since it has a natural variability in the way it produces and transport the sediments. The accumulation rate for neritic and pelagic sediments is often described as highly variable and much slower, respectively. Moreover, the distribution of sediments on the continental shelf is further complicated by the existence of relict sediments which came from pre-existing and exposed areas of the shelf during times of low sea level (Herman, n.d.).
Furthermore, sediment can be classified based on its particle source (Sverdrup et al., 2005). Lithogenous sediments are particles from volcanoes, airborne dust and eroded rocks. These are usually located in the neritic region. Biogenous sediments originated from living matter. The location of this sediment is in regions where there is high surface productivity. It is dominant in the pelagic region. Hydrogenous sediments came from chemical precipitation of sea water. It is dominant in mid-ocean ridges – the neritic-pelagic zone. Lastly, cosmogenous sediments are from space residuals. It has low concentration and can be found anywhere in the sea floor.

References

Herman, K. A. (n.d.). Sediments of the seafloor. Retrieved from http://pubs.usgs.gov/circ/c1198/chapters/090-100_Sediment.pdf
Sverdrup, K., Duxbury, A. & Duxbury, A. (2005). “The sea floor and its sediments.” An introduction to the world’s oceans. (8th ed.). McGraw-Hill Higher Education. Retrieved from http://highered.mheducation.com/sites/dl/free/0072528079/118961/ch04.pdf