[5] The large[6] guyot rises over 4 kilometres (2.5 mi)[7] from the eastern flank of the Tonga Trench[2] to a depth of 360 metres (1,180 ft).

[1] It features a 15 kilometres (9.3 mi) wide[7] flat top at 800–1,000 metres (2,600–3,300 ft) depth, which tilts gently westwards.

[13] Dredging has yielded pelagic ooze containing abyssal clay, basaltic breccia, dark pumice, dead corals, fecal pellets, fossils of foraminifera, gastropods and pteropods, limestones with brown manganese dioxide encrustations, otoliths and sand.

[3] Capricorn Seamount likely formed in the Miocene (23-5 million years ago[11]) as a volcano, perhaps part of a hotspot track which also includes Niue.

[18] It is unclear whether it ever featured coral reefs as no evidence of such growth has been found[19] although foraminifera data point to their past existence.