The Phoenix Plate (also known as the Aluk Plate) was an ancient tectonic plate that existed during the mid-Cretaceous through early Tertiary time. The Phoenix Plate began subducting under the Antarctic Plate. The Phoenix Ridge, a mid-oceanic ridge between the Pacific and the Phoenix Plates which had a spreading rate of 18-20 cm per year until around 84 Ma. A major decrease in spreading rate, and the convergence rate with the Antarctic Plate occurred around 52.3 Ma. During the Late Cretaceous, the Phoenix Plate fragmented into the Charcot Plate, much in the same way in which the Rivera and the Cocos Plate were formed by the fragmentation of the Farallon Plate.