Editing Atlantic Ocean (section)

=== North Atlantic ===
{{See also|Opening of the North Atlantic Ocean|NATO}}

Geologically, the North Atlantic is the area delimited to the south by two conjugate margins, Newfoundland and Iberia, and to the north by the Arctic [[Eurasian Basin]]. The opening of the North Atlantic closely followed the margins of its predecessor, the [[Iapetus Ocean]], and spread from the central Atlantic in six stages: [[Iberian Peninsula|Iberia]]–[[Newfoundland (island)|Newfoundland]], [[Porcupine Bank|Porcupine]]–North America, Eurasia–Greenland, Eurasia–North America. Active and inactive spreading systems in this area are marked by the interaction with the [[Iceland hotspot]].<ref>{{Harvnb|Seton|Müller|Zahirovic|Gaina|2012|loc=Northern Atlantic, p. 220}}</ref>

Seafloor spreading led to the extension of the crust and the formation of troughs and sedimentary basins. The Rockall Trough opened between 105 and 84 million years ago although the rift failed along with one leading into the [[Bay of Biscay]].{{sfn|Fitton|Larsen|1999|p=15}}

Spreading began opening the [[Labrador Sea]] around 61 million years ago, continuing until 36 million years ago. Geologists distinguish two magmatic phases. One from 62 to 58 million years ago predates the separation of Greenland from northern Europe while the second from 56 to 52 million years ago happened as the separation occurred.

[[Iceland Plateau|Iceland]] began to form 62 million years ago due to a particularly concentrated mantle plume. Large quantities of [[basalt]] erupted at this time period are found on Baffin Island, Greenland, the Faroe Islands, and Scotland, with ash falls in Western Europe acting as a stratigraphic marker.{{sfn|Fitton|Larsen|1999|p=10}} The opening of the North Atlantic caused a significant uplift of continental crust along the coast. For instance, despite 7&nbsp;km thick basalt, Gunnbjorn Field in East Greenland is the highest point on the island, elevated enough that it exposes older Mesozoic sedimentary rocks at its base, similar to old lava fields above sedimentary rocks in the uplifted Hebrides of western Scotland.{{Sfn|Fitton|Larsen|1999|pp=23–24}}

The North Atlantic Ocean contains about 810 [[seamount]]s, most of them situated along the Mid-Atlantic Ridge.<ref>Gubbay S. 2003. Seamounts of the northeast Atlantic. OASIS (Oceanic Seamounts: an Integrated Study). Hamburg & WWF, Frankfurt am Main, Germany</ref> The [[OSPAR Convention|OSPAR]] database (Convention for the Protection of the Marine Environment of the North-East Atlantic) mentions 104 seamounts: 74 within national [[exclusive economic zone]]s. Of these seamounts, 46 are located close to the [[Iberian Peninsula]].