Question: When did the ocean located in the Antarctic Circle come into existence?

full_context: Document 1: Geological history of Earth: The Cenozoic Era covers the 66 million years since the Cretaceous–Paleogene extinction event up to and including the present day. By the end of the Mesozoic era, the continents had rifted into nearly their present form. Laurasia became North America and Eurasia, while Gondwana split into South America, Africa, Australia, Antarctica and the Indian subcontinent, which collided with the Asian plate. This impact gave rise to the Himalayas. The Tethys Sea, which had separated the northern continents from Africa and India, began to close up, forming the Mediterranean sea.
Document 2: Antarctica: Antarctica (US English i/æntˈɑːrktɪkə/, UK English /ænˈtɑːktɪkə/ or /ænˈtɑːtɪkə/ or /ænˈɑːtɪkə/)[Note 1] is Earth's southernmost continent, containing the geographic South Pole. It is situated in the Antarctic region of the Southern Hemisphere, almost entirely south of the Antarctic Circle, and is surrounded by the Southern Ocean. At 14,000,000 square kilometres (5,400,000 square miles), it is the fifth-largest continent in area after Asia, Africa, North America, and South America. For comparison, Antarctica is nearly twice the size of Australia. About 98% of Antarctica is covered by ice that averages 1.9 km (1.2 mi; 6,200 ft) in thickness, which extends to all but the northernmost reaches of the Antarctic Peninsula.
Document 3: Queen Elizabeth Land: Queen Elizabeth Land is portion of mainland Antarctica named by the government of the United Kingdom and claimed as part of the British Antarctic Territory, which is the largest of the 14 British Overseas Territories. Situated south of Weddell Sea and between longitudes 20°W and 80°W, stretching from Filchner-Ronne Ice Shelf to the South Pole. That territory was unnamed until 2012, though most of it was unofficially known as Edith Ronne Land in 1947–68 and includes areas claimed by the United Kingdom, Chile and Argentina.
Document 4: Antarctica: New claims on Antarctica have been suspended since 1959 although Norway in 2015 formally defined Queen Maud Land as including the unclaimed area between it and the South Pole. Antarctica's status is regulated by the 1959 Antarctic Treaty and other related agreements, collectively called the Antarctic Treaty System. Antarctica is defined as all land and ice shelves south of 60° S for the purposes of the Treaty System. The treaty was signed by twelve countries including the Soviet Union (and later Russia), the United Kingdom, Argentina, Chile, Australia, and the United States. It set aside Antarctica as a scientific preserve, established freedom of scientific investigation and environmental protection, and banned military activity on Antarctica. This was the first arms control agreement established during the Cold War.
Document 5: Opening of the North Atlantic Ocean: Rocks from the North Atlantic Igneous Province have been found in Greenland, the Irminger Basin, Faroe Islands, Vøring Plateau (off Norway), Faroe - Shetland Basin, Hebrides, Outer Moray Firth and Denmark. The supercontinent known as Pangea existed during the late Paleozoic and early Mesozoic eras and began to rift around 200 million years ago. Pangea had three major phases of breakup. The first major phase began in the Early - Middle Jurassic, taking place between North America and Africa. The second major phase of breakup began in the Early Cretaceous. The South Atlantic Ocean opened around 140 million years ago as Africa separated from South America, and about the same time, India separated from Antarctica and Australia, forming the central Indian Ocean. The final major phase of breakup occurred in the early Cenozoic, as Laurentia separated from Eurasia. As the two plates broke free from each other, the Atlantic Ocean continued to expand.
Document 6: Southern Ocean: By way of his voyages in the 1770s, Captain James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian Oceans, instead. However, according to Commodore John Leech of the International Hydrographic Organization (IHO), this situation has no scientific sense since it has different ecosystem and life from the three oceans mentioned before and is located on a southern portion of Earth, hence the name of an ocean. This remains the current official policy of the IHO, since a 2000 revision of its definitions including the Southern Ocean as the waters south of the 60th parallel has not yet been adopted. Others regard the seasonally - fluctuating Antarctic Convergence as the natural boundary.
Document 7: 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.
Document 8: Wilkes Land: Wilkes Land is a large district of land in eastern Antarctica, formally claimed by Australia as part of the Australian Antarctic Territory, though the validity of this claim has been placed for the period of the operation of the Antarctic Treaty, to which Australia is a signatory. It fronts on the southern Indian Ocean between Queen Mary Coast and Adelie Land, extending from Cape Hordern in 100°31' E to Pourquoi Pas Point, in 136°11' E. The region extends as a sector about 2600 km towards the South Pole, with an estimated land area of 2,600,000 km², mostly glaciated. It is further subdivided in the following coastal areas which can also be thought of as sectors extending to the South Pole:
Document 9: Geology of Antarctica: More than 170 million years ago, Antarctica was part of the supercontinent Gondwana. Over time Gondwana broke apart and Antarctica as we know it today was formed around 35 million years ago.
Document 10: Geological history of Earth: Antarctica continued to become more isolated and finally developed a permanent ice cap. Mountain building in western North America continued, and the Alps started to rise in Europe as the African plate continued to push north into the Eurasian plate, isolating the remnants of Tethys Sea. A brief marine incursion marks the early Oligocene in Europe. There appears to have been a land bridge in the early Oligocene between North America and Europe since the faunas of the two regions are very similar. During the Oligocene, South America was finally detached from Antarctica and drifted north toward North America. It also allowed the Antarctic Circumpolar Current to flow, rapidly cooling the continent.
Document 11: Antarctic Circle: 66 ° 34 ′ S 0 ° 0 ′ E ﻿ / ﻿ 66.567 ° S 0.000 ° E ﻿ / - 66.567; 0.000 ﻿ (Prime Meridian) Southern Ocean North of Queen Maud Land and Enderby Land
Document 12: Antarctica: Positioned asymmetrically around the South Pole and largely south of the Antarctic Circle, Antarctica is the southernmost continent and is surrounded by the Southern Ocean; alternatively, it may be considered to be surrounded by the southern Pacific, Atlantic, and Indian Oceans, or by the southern waters of the World Ocean. It covers more than 14,000,000 km2 (5,400,000 sq mi), making it the fifth-largest continent, about 1.3 times as large as Europe. The coastline measures 17,968 km (11,165 mi) and is mostly characterized by ice formations, as the following table shows:
Document 13: Geological history of Earth: During the Eocene (56 million years ago - 33.9 million years ago), the continents continued to drift toward their present positions. At the beginning of the period, Australia and Antarctica remained connected, and warm equatorial currents mixed with colder Antarctic waters, distributing the heat around the world and keeping global temperatures high. But when Australia split from the southern continent around 45 Ma, the warm equatorial currents were deflected away from Antarctica, and an isolated cold water channel developed between the two continents. The Antarctic region cooled down, and the ocean surrounding Antarctica began to freeze, sending cold water and ice floes north, reinforcing the cooling. The present pattern of ice ages began about 40 million years ago.[citation needed]
Document 14: Wilkes Land: Wilkes Land is a large district of land in eastern Antarctica, formally claimed by Australia as part of the Australian Antarctic Territory, though the validity of this claim has been placed for the period of the operation of the Antarctic Treaty, to which Australia is a signatory. It fronts on the southern Indian Ocean between Queen Mary Coast and Adelie Land, extending from Cape Hordern in 100°31' E to Pourquoi Pas Point, in 136°11' E. The region extends as a sector about 2600 km towards the South Pole, with an estimated land area of 2,600,000 km², mostly glaciated. It is further subdivided in the following coastal areas which can also be thought of as sectors extending to the South Pole:
Document 15: Antarctic Plate: The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau and extending outward under the surrounding oceans. After breakup from Gondwana (the southern part of the supercontinent Pangea), the Antarctic plate began moving the continent of Antarctica south to its present isolated location causing the continent to develop a much colder climate. The Antarctic Plate is bounded almost entirely by extensional mid-ocean ridge systems. The adjoining plates are the Nazca Plate, the South American Plate, the African Plate, the Somali Plate, the Indo-Australian Plate, the Pacific Plate, and, across a transform boundary, the Scotia Plate.
ground_truth: roughly 30 million years ago
sub_queries: name the ocean which is located within antarctic circle Answer: Southern Ocean
when did Southern Ocean come into existence Answer: roughly 30 million years ago