Cruise ships at dock, Ushuaia, Tierra del Fuego, Argentina. Photo Credit: Rodolfo Pace
Dialogo Americas reports China is once again pressuring Argentina to build a naval base in Ushuaia, Tierra del Fuego, at the Southern tip of South America.
There is no indication that Argentina is accepting the Chinese offer, but I can understand both why the Chinese are making the offer and why it would be attractive to Argentina.
The current Antarctic treaty is set to expire in 2048. It seems unlikely it will be renewed. Too many want to exploit mineral wealth that is believed to be there. There are already known conflicting claims on the continent, including overlapping claims by Argentina, Chile, and the UK. Even Japan has stated an intention to make a claim. 
Neither the US nor China has made a claim yet, but they are likely to. The US has a strong basis for claims, and China has been investing heavily in Antarctic exploration and research.
Argentina has few friends likely to support their claim. Relations with the UK and the US have never fully recovered since the Falklands War. Relations with Chile have always been strained. Argentina’s military is now much weaker relative to the UK than it was at the time of the Falklands War, but they still claim the Falkland (Malvinas) and South Georgia, both of which are under UK administration. Argentina might want to have China on their side.
Chuck Hill's CG Blog 
Just think, if the Argentina allows it, it would put some serious pressure on the UK and it would force the UK into a corner.
I remember reading in Vice-Admiral Le Bailly’s writings a ‘minor driver’ for the Falklands War was to deny the Soviets being able to use the anchorages around the Falklands. The UK doesn’t have the resources to keep more ‘Down South’. I fear we would have to open up MPA to the US and NATO.