Azores–Gibraltar transform fault: Difference between revisions
Fama Clamosa (talk | contribs) +closure of Atlantic |
Fama Clamosa (talk | contribs) m reorg |
||
| Line 1: | Line 1: | ||
The '''Azores–Gibraltar Transform Fault''' ('''AGFZ'''), also called a [[fault (geology)|fault zone]] and a [[fracture zone]], is a major seismic fault in the Central [[Atlantic Ocean]] west of the [[Strait of Gibraltar]]. It is the product of the complex interaction between the [[African Plate|African]], [[Eurasian Plate|Eurasian]], and [[Iberian Plate|Iberian]] plates.<ref name="Rich-etal">{{Harvnb|Richardson|Musson|Horsburgh|2006|loc=Appendix A, Tectonics of the Azores-Gibraltar fault zone, pp. 94–97}}</ref> |
The '''Azores–Gibraltar Transform Fault''' ('''AGFZ'''), also called a [[fault (geology)|fault zone]] and a [[fracture zone]], is a major seismic fault in the Central [[Atlantic Ocean]] west of the [[Strait of Gibraltar]]. It is the product of the complex interaction between the [[African Plate|African]], [[Eurasian Plate|Eurasian]], and [[Iberian Plate|Iberian]] plates.<ref name="Rich-etal">{{Harvnb|Richardson|Musson|Horsburgh|2006|loc=Appendix A, Tectonics of the Azores-Gibraltar fault zone, pp. 94–97}}</ref> |
||
| ⚫ | |||
Forming the Atlantic segment of the boundary between the African and Eurasian plates, the AGFZ is largely dominated by compressional forces between these converging (3.8–5.6 mm/yr) plates, but it is subject of a dynamic tectonic regime also involving extension, transcurrent, and compression. The [[oceanic crust|oceanic]] [[lithosphere]] in the area is one of the oldest preserved on Earth directly related to the [[opening of the North Atlantic Ocean]].<ref name="MartLori-intro">{{Harvnb|Martínez‐Loriente|Sallarès|Gràcia|Bartolome|2014|loc=Introduction, p. 127}}</ref> |
Forming the Atlantic segment of the boundary between the African and Eurasian plates, the AGFZ is largely dominated by compressional forces between these converging (3.8–5.6 mm/yr) plates, but it is subject of a dynamic tectonic regime also involving extension, transcurrent, and compression. The [[oceanic crust|oceanic]] [[lithosphere]] in the area is one of the oldest preserved on Earth directly related to the [[opening of the North Atlantic Ocean]].<ref name="MartLori-intro">{{Harvnb|Martínez‐Loriente|Sallarès|Gràcia|Bartolome|2014|loc=Introduction, p. 127}}</ref> |
||
| Line 7: | Line 8: | ||
The western end of the AGFZ, the [[Azores Triple Junction]] on the [[Mid-Atlantic Ridge]] (MAR), is where the North American, African, and Eurasian plates meet. Spreading in the MAR is faster south of the AGFZ than north of it, which results in a [[transform fault|trancurrent]] movement along the AGFZ at about {{convert|4|mm/yr|abbr=on}}.<ref name="Rich-etal" /> |
The western end of the AGFZ, the [[Azores Triple Junction]] on the [[Mid-Atlantic Ridge]] (MAR), is where the North American, African, and Eurasian plates meet. Spreading in the MAR is faster south of the AGFZ than north of it, which results in a [[transform fault|trancurrent]] movement along the AGFZ at about {{convert|4|mm/yr|abbr=on}}.<ref name="Rich-etal" /> |
||
The eastern segment of the fault is complex and characterised by a series of seamounts and ridges separating the [[Tores Abyssal Plain|Tores]] and [[Horseshoe Abyssal Plain|Horseshoe]] abyssal plains. The active compressional deformation in this segment is an extremely rare example of compression between two oceanic litospheres.<ref name="Rich-etal" /> |
The eastern segment of the fault is complex and characterised by a series of seamounts and ridges separating the [[Tores Abyssal Plain|Tores]] and [[Horseshoe Abyssal Plain|Horseshoe]] abyssal plains. The active compressional deformation in this segment is an extremely rare example of compression between two oceanic litospheres.<ref name="Rich-etal" /> |
||
| ⚫ | |||
The Atlantic Ocean is surrounded by [[passive margin]]s with the exception of three subduction zones: the [[Lesser Antilles Volcanic Arc|Lesser Antilles Arc]], [[Scotia Arc]], and the [[Gibraltar Arc]]. The Gibraltar Arc in the western [[Mediterranean]] is propagating westward into the Atlantic over an east-dipping oceanic slab. This subduction/[[back-arc basin]] system is developing along the AGFZ in front of the Alboran Block (under the [[Alboran Sea]]) at a rate faster than that of the Africa-Iberia convergence. Consequently, this area is a rare case of a passive margin slowly being transformed into an [[active margin]]. In the context of the [[Wilson Cycle]], this indicate that the beginning of the closure of the Atlantic is taking place at the AGFZ.<ref>{{Harvnb|Duarte|Rosas|Terrinha|Schellart|2013|loc=Introduction, pp. 839–840}}</ref> |
The Atlantic Ocean is surrounded by [[passive margin]]s with the exception of three subduction zones: the [[Lesser Antilles Volcanic Arc|Lesser Antilles Arc]], [[Scotia Arc]], and the [[Gibraltar Arc]]. The Gibraltar Arc in the western [[Mediterranean]] is propagating westward into the Atlantic over an east-dipping oceanic slab. This subduction/[[back-arc basin]] system is developing along the AGFZ in front of the Alboran Block (under the [[Alboran Sea]]) at a rate faster than that of the Africa-Iberia convergence. Consequently, this area is a rare case of a passive margin slowly being transformed into an [[active margin]]. In the context of the [[Wilson Cycle]], this indicate that the beginning of the closure of the Atlantic is taking place at the AGFZ.<ref>{{Harvnb|Duarte|Rosas|Terrinha|Schellart|2013|loc=Introduction, pp. 839–840}}</ref> |
||
Revision as of 11:52, 29 October 2016
The Azores–Gibraltar Transform Fault (AGFZ), also called a fault zone and a fracture zone, is a major seismic fault in the Central Atlantic Ocean west of the Strait of Gibraltar. It is the product of the complex interaction between the African, Eurasian, and Iberian plates.[1] The AGFZ produced the large-magnitude 1755 Lisbon and 1969 Horseshoe earthquakes and, consequently, a number of large tsunamis.[2]
Forming the Atlantic segment of the boundary between the African and Eurasian plates, the AGFZ is largely dominated by compressional forces between these converging (3.8–5.6 mm/yr) plates, but it is subject of a dynamic tectonic regime also involving extension, transcurrent, and compression. The oceanic lithosphere in the area is one of the oldest preserved on Earth directly related to the opening of the North Atlantic Ocean.[2]
It runs eastward from the eastern end of the Terceira Rift in the Azores and extends east through the Strait of Gibraltar and into the Mediterranean Sea. The section east of Gibraltar is poorly understood and is currently regarded as a "diffuse" boundary. Many geologists believe the fault connects with a subduction zone where the African Plate is slowly subducting beneath the Eurasian Plate somewhere in the vicinity of the Italian Peninsula.[1]
The western end of the AGFZ, the Azores Triple Junction on the Mid-Atlantic Ridge (MAR), is where the North American, African, and Eurasian plates meet. Spreading in the MAR is faster south of the AGFZ than north of it, which results in a trancurrent movement along the AGFZ at about 4 mm/a (0.0050 in/Ms).[1] The eastern segment of the fault is complex and characterised by a series of seamounts and ridges separating the Tores and Horseshoe abyssal plains. The active compressional deformation in this segment is an extremely rare example of compression between two oceanic litospheres.[1]
The Atlantic Ocean is surrounded by passive margins with the exception of three subduction zones: the Lesser Antilles Arc, Scotia Arc, and the Gibraltar Arc. The Gibraltar Arc in the western Mediterranean is propagating westward into the Atlantic over an east-dipping oceanic slab. This subduction/back-arc basin system is developing along the AGFZ in front of the Alboran Block (under the Alboran Sea) at a rate faster than that of the Africa-Iberia convergence. Consequently, this area is a rare case of a passive margin slowly being transformed into an active margin. In the context of the Wilson Cycle, this indicate that the beginning of the closure of the Atlantic is taking place at the AGFZ.[3]
References
- ^ a b c d Richardson, Musson & Horsburgh 2006, Appendix A, Tectonics of the Azores-Gibraltar fault zone, pp. 94–97
- ^ a b Martínez‐Loriente et al. 2014, Introduction, p. 127
- ^ Duarte et al. 2013, Introduction, pp. 839–840
Sources
- Duarte, J. C.; Rosas, F. M.; Terrinha, P.; Schellart, W. P.; Boutelier, D.; Gutscher, M. A.; Ribeiro, A. (2013). "Are subduction zones invading the Atlantic? Evidence from the southwest Iberia margin" (PDF). Geology. 41 (8): 839–842. doi:10.1130/G34100.
{{cite journal}}: Invalid|ref=harv(help) - Martínez‐Loriente, S.; Sallarès, V.; Gràcia, E.; Bartolome, R.; Dañobeitia, J. J.; Zitellini, N. (2014). "Seismic and gravity constraints on the nature of the basement in the Africa‐Eurasia plate boundary: New insights for the geodynamic evolution of the SW Iberian margin" (PDF). Journal of Geophysical Research: Solid Earth. 119 (1): 127–149. doi:10.1002/2013JB010476. Retrieved 29 October 2016.
{{cite journal}}: Invalid|ref=harv(help) - Richardson, S.; Musson, R.; Horsburgh, K. (2006). Tsunamis–Assessing the hazard for the UK and Irish coast (PDF (7.8Mb)). 41st Defra Flood and Coastal Management Conference. York, UK. Retrieved 29 October 2016.
{{cite conference}}: Invalid|ref=harv(help)
 | This tectonics article is a stub. You can help Wikipedia by expanding it. |
 | This Gibraltar-related article is a stub. You can help Wikipedia by expanding it. |