The region northwest of Easter Island is characterized by the Easter Microplate, a plate set within the East Pacific Rise. Two rift zones delimit eastward and westward, while the Pito and the Orongo fracture zones form its northern and southern border, respectively. Pito seamount lies on the fracture zone of the same name[2] and may indicate incipient seafloor spreading.[2]
Pito seamount has an 18 kilometres (11 mi) wide base,[5] rises to a depth of 2,250 metres (7,380 ft) and features a 50 metres (160 ft) deep and almost 1 kilometre (0.62 mi) wide axial valley.[6] Several smaller cones dot Pito's surface,[5] and the seafloor depression, Pito Deep, lies northwest of the seamount.[7] Fresh basalticpillow lavas with geochemical characteristics typical of mid-ocean ridge basalts occur on Pito,[8] as do sheet and lobate lava flows. The lavas often have a glassy surface.[9]
The first black smokers have been found at depths of 2,243 metres (7,359 ft) at the foot of Pito seamount.[3] A number of black smoker fields are found on Pito and are named Abe, Jason, Magnificent Village, Medea, Scotty's Castle and Sentry; the field originally discovered in 1993 is Magnificent Village and is also the largest. About fifty vents, some active and others inactive, have been observed in the summit area. Temperatures range 338–370 °C (640–698 °F).[6] Extensive faulting in the region may aid in the establishment of a hydrothermal circulation.[10]
^ abMartinez, Fernando; Naar, David F.; Reed, Thomas B.; Hey, Richard N. (December 1991). "Three-dimensional SeaMARC II, gravity, and magnetics study of large-offset rift propagation at the Pito Rift, Easter microplate". Marine Geophysical Researches. 13 (4): 273. Bibcode:1991MarGR..13..255M. doi:10.1007/bf00366279. ISSN0025-3235. S2CID129047311.
^ abcdJ., Cheadle, M.; E., John, B.; R., German, C.; S., Gee, J.; A., Coogan, L.; M., Gillis, K.; S., Swapp (December 2017). "Pito Seamount revisited: the discovery and mapping of new black smoker vents". AGU Fall Meeting Abstracts. 2017: V51D–0388. Bibcode:2017AGUFM.V51D0388C.{{cite journal}}: CS1 maint: multiple names: authors list (link)
Naar, D. F.; Hekinian, R.; Segonzac, M.; Francheteau, J.; Armijo, R.; Cogne, J.-P.; Constantin, M.; Girardeau, J.; Hey, R. N.; Searle, R. C. (19 March 2013). Vigorous Venting and Biology at Pito Seamount, Easter Microplate. Geophysical Monograph Series. pp. 305–318. doi:10.1029/148gm13. ISBN9781118665879. {{cite book}}: |journal= ignored (help)
Verati, Chrystèle; de Donato, Philippe; Prieur, Daniel; Lancelot, Joël (June 1999). "Evidence of bacterial activity from micrometer-scale layer analyses of black-smoker sulfide structures (Pito Seamount Site, Easter microplate)". Chemical Geology. 158 (3–4): 257–269. Bibcode:1999ChGeo.158..257V. doi:10.1016/S0009-2541(99)00054-6. ISSN0009-2541.