The seamounts were constructed on young oceanic crust during the Cretaceous, but a second phase of volcanic activity took place during the Eocene.

[7] Among the seamounts known by name are:[16][5][17][18] [21][19] Has reactivated volcanism[24] The Pacific Ocean floor beneath the seamounts is of Cretaceous age and is subdivided by the Murray Fracture Zone into an older northern (100 to 95 million years ago) and a younger southern (80 to 85 million years ago) sector.

Minerals contained in the rocks consist of aegirine, augite, clinopyroxene, feldspar, oxidized olivine, orthopyroxene, plagioclase and pyroxene.

[1] Plate reconstructions for the time period based on the dates of the northwest–southeast trend and the older Line Islands are consistent with each other.

[31] The oldest is a sample from one of the Northwest cluster at 98.1 Ma[2] It is possible that their formation was influenced by the nearby presence of a spreading ridge,[32] a process which has been suggested for other hotspots such as Réunion, Iceland, Azores and others as well.

[1] This process is similar to that that formed the Wolf-Darwin linement extending from the present Galápagos hotspot.

[10] Technically this could be explained in plate tectonics as a process of asthenosphere related flow allowing buoyant melt from the hotspot being channelled towards the active spreading center.

[10] Alternative earlier explanations for the formation of the Musicians Seamounts is the presence of a former spreading ridge at their site,[25] and crustal weaknesses associated with the so-called "bending line" in the region which was formed by a change in the motion of the Pacific plate.

[40] About 10,000 seamounts and islands are estimated to dot the floor of the Pacific Ocean, forming clusters and chains.

[44] Pacific plate motion was stable in its general north-west vector from the initial formation of the Northwest Cluster,[45] and can be calculated to be 42 ± 9 km (26.1 ± 5.6 mi)/million years.

[45] Other evidence has suggested that the next change in Pacific plate rotation poles was between 54 and 47 million years ago which may have allowed extension volcanism in the southern part of the chain.

[46] Deep sea corals and sponges grow on the Musicians Seamounts;[47] corals identified include Antipathes, Acanthogorgia, chrysogorgidae, Hemicorallium, isididae, Paracalyptrophora, Pleurogorgia and primnoids, while sponges include Caulophacus, Hyalostylus, Poliopogon and Saccocalyx.

[48] On the Beethoven Ridge which is the deeper of these three at between 2,300 and 2,531 m (7,546 and 8,304 ft), the dominant species by far are anthomastus corals and the sponge density is also very high.