when did the antarctic ocean become an ocean
Southern Ocean The Southern Ocean, geologically the youngest of the oceans, was formed when Antarctica and South America moved apart, opening the Drake Passage, roughly 30 million years ago. The separation of the continents allowed the formation of the Antarctic Circumpolar Current.
Arctic Ocean The climate of the Arctic region has varied significantly in the past. As recently as 55 million years ago, during the Paleocene–Eocene Thermal Maximum, the region reached an average annual temperature of 10–20 °C (50–68 °F).[26] The surface waters of the northernmost[27] Arctic Ocean warmed, seasonally at least, enough to support tropical lifeforms[28] requiring surface temperatures of over 22 °C (72 °F).[29]