Antarctic Treaty
You may be thinking of the Antarctic Treaty.
There is no agreement that 'splits up' Antarctica. Antarctica -- and all of earth south of 60 degrees South Latitude -- is governed by the Antarctic Treaty. This treaty negates all previous land claims and prohibits new land claims on the continent.
No continents have claims on Antarctica.
No, however, Argentina claims a sector of Antarctica called Argentine Antarctica: almost a million square kilometres of land.
There isn't one. For example, neither the United States nor many other countries recognize the claims by ANY country to land in Antarctica. D.A.W.
Australia claims a slice of Antarctica, but does not own it. There are other claims, and no country with claims owns any part of Antarctica.
The Antarctic Treaty negates all existing claims and prohibits any future claims, as of 1960, when it was enacted by agreement of the governments representing 80% of the earth's population.
Australia claims part of Antarctica, but owns none of it, nor does any other country with territorial claims on the continent.
Antarctica is the continent that does not have a single country located on it. Although several countries have territorial claims on Antarctica, these claims are not universally recognized.
New Zealand claims part of the Antarctic territory, but does not 'run' any of it. The Antarctic Treaty preserves the continent for the study of science. Claims are unacknowledged.
Argentina owns zero in Antarctica. Its claim overlaps other claims. All claims are held in abeyance by the Antarctic Treaty (1961).
No, no nation owns any part of Antarctica. Several nations have territorial claims on the continent -- not USA, however -- some of which overlap each other. The Antarctic Treaty (1960) holds all claims in abeyance and forbids any other future claims.