The Phoenix plate (alternatively Aluk or Drake) was an oceanic plate that operated from the early Paleozoic into the late Cenozoic and played a long‑lived role in plate interactions across Panthalassa and the southwestern Pacific. Its early history included establishment of a triple junction with the Izanagi and Farallon plates by at least ~410 Ma and active subduction beneath the eastern margin of Gondwana. By the early Jurassic (~180 Ma) the plate had become an integral component of Pacific‑realm tectonics, although subsequent Mesozoic reorganizations reduced it from a once‑extensive oceanic domain to a mostly extinct plate of which only a small fragment survives today.
Between about 150 and 130 Ma the Pacific plate formed at the Izanagi–Farallon–Phoenix junction, producing new triple junction geometries (Izanagi–Pacific–Phoenix and Farallon–Pacific–Phoenix) and fundamentally altering boundary configurations in the Pacific. Around 120 Ma the east‑of‑Australia segment of Phoenix ceased to subduct and evolved into a transform/transpressional boundary that persisted until roughly 80 Ma; contemporaneously, portions of the plate continued to descend southward driven by subduction beneath the Antarctic Peninsula during the Late Cretaceous. During the Late Cretaceous to early Cenozoic the southwestern sector broke apart, producing the Charcot plate in a process analogous to later fragmentations of the Farallon plate.
Following these reorganizations a mid‑ocean spreading center—the Antarctic–Phoenix Ridge—developed between the Antarctic and Phoenix plates, with divergent margins also bordering the Bellingshausen and Pacific plates in the southwestern Pacific. A pronounced kinematic change at ~52.3 Ma sharply reduced spreading on that ridge and slowed Phoenix–Antarctic convergence; a segment of the ridge was later consumed by subduction between ~50 and 43 Ma. Although subduction of Phoenix lithosphere continued intermittently for over 100 Myr, seafloor spreading on the Antarctic–Phoenix Ridge declined through the Neogene and effectively ceased by ~3.3 Ma, after which the residual Phoenix lithosphere was assimilated into the Antarctic plate.
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The present‑day remnant of the Phoenix plate underlies the southwestern Drake Passage. This fragment is bounded by recognizable tectonic features: the Shackleton fracture zone to the northeast, the Hero fracture zone to the southwest, the South Shetland Trough to the southeast, and the now‑inactive Antarctic–Phoenix Ridge to the northwest.