Question: What latitude is the border of the continent where Grass Bluff is located?

full_context: Document 1: Gratton Nunatak: Gratton Nunatak () is a bare, linear nunatak lying at the south side of the mouth of McCarthy Glacier, Antarctica, where the latter enters Reedy Glacier. It was mapped by the United States Geological Survey from surveys and U.S. Navy air photos, 1960–64, and was named by the Advisory Committee on Antarctic Names for John W. Gratton, a construction mechanic at Byrd Station in 1962.
Document 2: Harrison Bluff: Harrison Bluff is a pale-colored trachyte headland forming the seaward termination of Trachyte Hill and marking the southern end of McDonald Beach on the western side of Mount Bird, Ross Island, Antarctica. Many skuas nest on the bluff. A survey station marked by a rock cairn was placed on the top of the northwest corner of the bluff by E.B. Fitzgerald of the Cape Bird party of the New Zealand Geological Survey Antarctic Expedition, 1958–59, and the bluff was named by the New Zealand Antarctic Place-Names Committee for J. Harrison, mountaineer-assistant with the expedition.
Document 3: Gray Peak (Antarctica): Gray Peak is a prominent rock summit in the Queen Maud Mountains of Antarctica. The mountain is located on the west side of Canyon Glacier, opposite the Hughes Range. The mountain was named in 1958 by the Advisory Committee on Antarctic Names (US-ACAN), after Thomas I. Gray, Jr., a meteorologist at Little America V.
Document 4: Miller Bluffs: The Miller Bluffs () are a line of steep, east-facing bluffs about long which extend west-northwest from Foros Spur at the mouth of Newcomer Glacier, along the northeast side of Gromshin Heights in northern Sentinel Range, Ellsworth Mountains in Antarctica. The north end of the feature was photographed by Lincoln Ellsworth on his trans-Antarctic flight of November 23, 1935, and the bluffs were mapped by the United States Geological Survey in 1961 from air photos obtained by U.S. Navy Squadron VX-6 in 1959. The feature was named by the Advisory Committee on Antarctic Names for the Hon. George P. Miller, former chairman of the House Science and Astronautics Committee, whose great interest in Antarctic activities was of assistance in assuring successful completion of U.S. research of that continent, 1958–72.
Document 5: National Antarctic Program: Till date 48 countries have signed the Antarctic Treaty which was drafted and negotiated back in 1959. Out of these, only 28 countries have the Consultative status i.e. these Parties have the right to participate in Antarctic Treaty Consultative Meetings (ATCM) and are accordingly known as Consultative Parties and their presence in Antarctica is shown by carrying substantial research there.
Document 6: 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 7: Australian Antarctic Data Centre: Article III.1.c of the Antarctic Treaty states that "to the greatest extent feasible and practicable" ... "scientific observations and results from Antarctica shall be exchanged and made freely available"
Document 8: Moraine Bluff: Moraine Bluff () is a bluff in Antarctica, high, on the east side of Skelton Glacier, lying north of Red Dike Bluff. It was surveyed and named in 1957 by the New Zealand party of the Commonwealth Trans-Antarctic Expedition (1956–58), and so named because a long morainic strip extends from the foot of the bluff on to Skelton Glacier.
Document 9: Alpha Bluff: Alpha Bluff () is a high bluff on the west side of Shults Peninsula, at the east side of Skelton Glacier in Antarctica. Surveyed and named in 1957 by the New Zealand party of the Commonwealth Trans-Antarctic Expedition (1956–58). Named after the first letter of the Greek alphabet because it is the most southerly of all bluffs on the Skelton Glacier.
Document 10: Bell Bluff: Bell Bluff () is a rock bluff on the west side of Beardmore Glacier, just north of the mouth of Garrard Glacier, Antarctica. It was named by the Advisory Committee on Antarctic Names for Charles A. Bell, Utilities Man, who wintered at Hallett Station in 1964.
Document 11: 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 12: Antarctica: In 1983, the Antarctic Treaty Parties began negotiations on a convention to regulate mining in Antarctica. A coalition of international organizations launched a public pressure campaign to prevent any minerals development in the region, led largely by Greenpeace International, which established its own scientific station—World Park Base—in the Ross Sea region and conducted annual expeditions to document environmental effects of humans on Antarctica. In 1988, the Convention on the Regulation of Antarctic Mineral Resources (CRAMRA) was adopted. The following year, however, Australia and France announced that they would not ratify the convention, rendering it dead for all intents and purposes. They proposed instead that a comprehensive regime to protect the Antarctic environment be negotiated in its place. The Protocol on Environmental Protection to the Antarctic Treaty (the "Madrid Protocol") was negotiated as other countries followed suit and on 14 January 1998 it entered into force. The Madrid Protocol bans all mining in Antarctica, designating Antarctica a "natural reserve devoted to peace and science".
Document 13: Antarctica: The Protocol on Environmental Protection to the Antarctic Treaty (also known as the Environmental Protocol or Madrid Protocol) came into force in 1998, and is the main instrument concerned with conservation and management of biodiversity in Antarctica. The Antarctic Treaty Consultative Meeting is advised on environmental and conservation issues in Antarctica by the Committee for Environmental Protection. A major concern within this committee is the risk to Antarctica from unintentional introduction of non-native species from outside the region.
Document 14: Grass Bluff: Grass Bluff () is a wedge-shaped rock bluff northwest of Fluted Peak, in the southern part of the Roberts Massif, Antarctica. It was named by the Advisory Committee on Antarctic Names for Robert D. Grass, a United States Antarctic Research Program meteorologist at South Pole Station, winter 1964.
Document 15: 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.
ground_truth: south of 60° S
sub_queries: Grass Bluff >> continent Answer: Antarctica
What latitude is defined as being Antarctica 's border? Answer: south of 60° S