Lomilik has a 40-by-15-kilometre-wide (24.9 mi × 9.3 mi) summit terrace with the proper summit at circa 1,500 metres (4,900 ft) depth; a scarp separates the two and small hills reach depths of 1,350 metres (4,430 ft). The summit terrace is covered by rocks with ooze in between. A notch in the southern flank of Lomilik was likely created by a landslide.[2][4] It is part of the Magellan Seamounts[5] and consists of a Cretaceousvolcano with a thin layer of carbonate rocks and ferromanganese.[6] Lami seamount lies northwest of Lomilik.[7]
The rocks found on Lomilik consist of basalt and limestone.[8]Fluorapatite, hyaloclastite,[9]mudstone, phosphorite and siltstone have been identified in rocks from the seamount.[10]Manganese nodules have been found on Lomilik[1] and the manganese crusts on the seamount reach thicknesses of over 10 centimetres (3.9 in);[11] the thickest crust recovered from an ocean is a 18 centimetres (7.1 in) thick ferromanganese crust from Lomilik recovered in 1989.[2] The deposits on Lomilik could potentially be mined.[12]
