The Amazon Canyon is a

submarine canyon A submarine canyon is a steep-sided valley cut into the seabed of the continental slope, sometimes extending well onto the continental shelf, having nearly vertical walls, and occasionally having canyon wall heights of up to , from canyon flo ...

within the Amazon Fan in the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, located approximately from the mouth of the Amazon River, near

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It covers an area of .John E. Damuth, Naresh Kumar, GSA Bulletin; June 1975; v. 86; no. 6; p. 863–878; , available a

It was formed in the mid to Late Miocene, late

Miocene period The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

. The canyon is believed to have formed through mass failures, and subsequently evolved through underwater erosion.William R. Normark and Paul R. Carlson, "Giant submarine canyons: Is size any clue to their importance in the rock record?", Extreme depositional environments: mega end members in geologic time, Geological Society of America: Boulder, Colorado, 2003, p 184. Because of its relatively small size, the canyon has been extensively mapped.

Technical background and channel lobes

Continental shelves off major river deltas and estuaries act as interfaces between terrestrial environments and depositional regimes in the deep sea. They serve as a large means of carbon recycling and are a source of carbon hydrates. The Amazon River is 6,770 km long and with its numerous tributaries drains a watershed of 7,050,000 km². The Amazon Shelf in front of the Amazon delta is more than 300 km wide. Despite how closely shelf sediment composition has been studied, very few high-resolution data have been published in the past about the shelf. In one study, we see that the Amazon channel-mouth lobe complex geometry indicates a strong interaction between lobe formation and pre-existing morphology created by deposition of previous channel-levee systems and lobes and seamounts.Jeguo, B., Savoyea, C., Pirmezc, L. Droz. 2008. “Channel-mouth Lobe Complex of the Recent Amazon Fan: The Missing Piece” Marine Geology. 19 (252): 62–77 As a result, this actually helped develop the Amazon fan lobes and overall structure.

Organic carbon loading and processing

Sediment cores from the Amazon deep sea fan recovered during R/V Meteor cruise 16-2 show in detail the modern areal distribution of sedimentary organic carbon, stable organic carbon isotopes of the organic matter (OM), as well as variations in the depositional processes.Schlünz, B., R.R Schneider., P.J Müller, W.J Showers., G Wefer. 1999. “Terrestrial organic carbon accumulation on the Amazon deep sea fan during the last glacial sea level low stand” ''Chemical Geology'' 8 (159)263–281. One of the conclusions of this study stated that organic carbon buildup on the Amazon deep sea fan is controlled by changes in glacioeustatic sea-levels.Schlünz, B., R.R Schneider., P.J Müller., W.J Showers., G Wefer. 1999. “Terrestrial organic carbon accumulation on the Amazon deep sea fan during the last glacial sea level low stand” ''Chemical Geology'' 8 (159)263–281. Additionally, only 7 to 12% of the terrestrial organic carbon discharged by the Amazon River was deposited on the Amazon fan during the time span of 10,000 years. According to Schlunz et al. 1999, their calculations indicate that about 10% of today's atmospheric carbon can be deposited in a fan system like the Amazon fan during a time-span of approximately 20,000 years. This implies that as excess carbon continues to be added to atmospheric systems, many other fans like the Amazon fan can potentially have a critical role in processing this excess carbon.

References

{{reflist Submarine canyons of the Atlantic Ocean

Technical background and channel lobes

Organic carbon loading and processing

See also

References