Cocos Ridge

Far fewer seamounts are found on the crest or the southeastern flank giving the ridge an overall asymmetric geometry.

[4] The ridge began to form immediately after the establishment of the Cocos–Nazca spreading centre in the late Oligocene.

Initially (at about 23 Ma) the spreading centre is interpreted to have had a relatively simple SW–NE trend, with the hotspot lying just on its northwestern side, starting the formation of the Cocos Ridge.

At about 3.5 Ma a new spreading centre developed briefly on the northwestern edge of the Cocos Ridge.

Geophysical investigations using seismic reflection and wide-angle techniques have been used to determine the internal structure of the ridge.

On the flanks of the ridge the lower crustal layer 3 is about 6 km thick, similar to average oceanic crust.

All the extra thickness observed in layers 2 and 3 is thought to be a result of past proximity to the Galápagos hotspot.