Abyssal hill
Anabyssal hillis a small hill that rises from the floor of anabyssal plain.They are the most abundantgeomorphicstructures onEarth,covering more than 30% of theocean floor.[1]Abyssal hills have relatively sharply defined edges and climb to heights of no more than a few hundred meters. They can be from a few hundred meters to kilometers in width. A region of the abyssal plain that is covered in such hill structures is termed an "abyssal-hills province". However, abyssal hills can also appear in small groups or in isolation.[2]
The greatest abundance of abyssal hills occurs on the floor of the Pacific Ocean.[1]These Pacific Ocean hills are typically 50–300 m (160–980 ft) in height, with a width of 2–5 km (1.2–3.1 mi) and a length of 10–20 km (6.2–12.4 mi).[3]They may be created along the flanks of the tectonically activeEast Pacific Riseashorst-and-grabenfeatures, then become stretched out with the passage of time.[1]Abyssal hills may also be areas of thickeroceanic crustthat were generated at themid-ocean ridgeduring times of increasedmagmaproduction.
References
[edit]- ^abcKennish, Michael J. (2001).Practical handbook of marine science.Marine science series (3rd ed.). CRC Press. p. 282.ISBN0-8493-2391-6.
- ^Heezen, Bruce C.; Laughton, A. S. (1963). "Abyssal Plains". In M. N. Hill (ed.).Earth Beneath Sea History Sea.Sea: Ideas and Observations on Progress in the Study of the Seas. Vol. 3. Harvard University Press. p. 312.ISBN0-674-01730-7.
- ^Dilek, Y. (1998). "Structure and tectonics of intermediate-spread oceanic crust drilled at DSDP/ODP Holes 504B and 896A, Costa Rica Rift". In Adrian Cramp (ed.).Geological evolution of ocean basins: results from the Ocean Drilling Program.Geological Society special publication. Vol. 131. Geological Society. p. 194.ISBN1-86239-003-7.