Coral Patch Seamount
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Ampére Seamount , and together with several neighbouring seamounts it is one of the Horseshoe Seamounts.
The seamount was probably formed by the Madeira hotspot in the Miocene, together with buckling processes in the oceanic crust. It was initially probably an island. There is evidence of submarine landslides and active faults which constitute a tsunami hazard; the 1755 Lisbon earthquake may have occurred north of the seamount. The name Coral Patch Seamount refers to the presence of cold water corals on the seamount. Their occurrence there was reported first in 1878, five years before the actual discovery of the seamount. They are only sparse on Coral Patch Seamount, probably due to lack of nutrients. A number of other submarine animals including fish have been observed.
Research history and nameAn expedition by the cold water corals dredged from the seamount; their occurrence was reported in 1878. The seamount was originally named "Coral Patch shoal": the term seamount was not yet in use at that time.[1][2] It is only poorly explored.[3]
Geography and geomorphology A number of seamounts exist in the northeastern Atlantic around the Azores, the Canary Islands and Madeira. They rise between abyssal plains from a seafloor at 4,000–4,800 metres (13,100–15,700 ft) to depths of usually a few hundred meters below sea level.[1] They are known as the Horseshoe Seamounts.[4]
Together with Ampére Seamount farther west Coral Patch Seamount forms the Ampére bank:[1] a 3,400 metres (11,200 ft) deep valley separates the two.[5] To the northeast lies Coral Patch Ridge[6] and north Gorringe Ridge, across the Horseshoe Abyssal Plain. The Seine Hills are located east of Coral Patch Seamount.[7]
Coral Patch Seamount has an elliptical outline, 120 kilometres (75 mi) long and 70 kilometres (43 mi) wide and trending east-northeast.[1] The shallowest point lies at a depth of about 645 metres (2,116 ft).[8] It consists of nine volcanic cones that overlie a sedimentary structural high; the cones and the structural high make up the seamount. The 8 kilometres (5.0 mi) wide 'Vince volcano' is the largest volcanic cone and forms a solitary northeasterly summit; the other eight are clustered in the southwest and one of these forms the shallowest point of the seamount.[1][6] The southern slopes are steep and feature canyon-like features, the northern slopes are more gentle.[8] Two faults, the North Coral Patch Ridge fault and the South Coral Patch Ridge fault, run northeastward away from Coral Patch Seamount.[9] Both have offset Holocene deposits and thus appear to be active.[10] Thrust faults separate Coral Patch Seamount from the Horseshoe Abyssal Plain.[11] The surface of the seamount is formed mainly by outcropping gullies and scarps occur on the seamount, the latter are evidence of past submarine landslides or mass wasting phenomena.[6]
GeologyThe lithospheric anomalies.[15] Buckling of the crust due to plate convergence is also responsible for the uplift of Coral Patch Seamount[16] and has pushed it over the Horseshoes Abyssal Plain.[11]
epicentre of which may have been located between Coral Patch Seamount and Gorringe BankEfforts at Ampére Seamount,[17] and a date of 31.2 ± 0.2 million years ago has been obtained for the Ampére-Coral Patch ridge.[18] Both seamounts were probably islands in the past.[19] The volcanic growth of the seamount was influenced by the wider tectonic regime, resulting in the east-northeast trending structure of the seamount. The tectonic regime would have favoured the ascent of magma from the Madeira hotspot away from its usual track.[20]
In the present-day, the region of Coral Patch Seamount is a potential source for March 31, 1761:[21] an earthquake was recorded close to the seamount on July 11, 1915.[22] In addition, the most common hypotheses for the source of the 1755 Lisbon earthquake localize it in the area between Coral Patch Seamount and Gorringe Bank.[23]
clinopyroxene, diopside and olivine phenocrysts and are heavily altered[26] with the formation of palagonite and zeolites.[25] Their geochemistry indicates that the magma forming them was influenced by crustal components.[18] Nonvolcanic rocks include pelagic carbonates,[2] biogenic carbonates generated by animal skeletons and foraminifera,[27] limestones and iron-manganese oxides.[17]
Life Many seamounts are biodiversity hotspots, as they interact with ocean currents enhancing the biological productivity around them. In the case of the northeast Atlantic seamounts, deep ocean currents are diverted at the seamount inducing upwelling. Outcropping rocks permit the settlement of species that would not find suitable substrates on sediment covered seafloor.[1] Underwater video has identified a number of animals living on Coral Patch Seamount, but in general animals are rare and suspension feeders.[3]
The seamount is heavily microorganisms, i.e., microorganisms that live within the rock.[33] This evidence may yield cues about the identification of past life on Mars, as the basaltic rocks could be a suitable environment.[34]
NotesReferences
Sources
External links Wikimedia Commons has media related to Coral Patch Seamount.
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