Today (0 Mya). Seven major plates carry the continents and ocean floor. The Atlantic widens at ~2 cm/yr along the Mid-Atlantic Ridge; the Pacific narrows along its subduction zones around the Ring of Fire.
Paleoshorelines: Scotese & Wright (2018) PALEOMAP PaleoDEMs (CC-BY 4.0). Plate rotations: Müller et al. (2019), EarthByte (CC-BY).