Argentina is apparently thinking that "if at first you don't succeed, try, try again." Or that is what it looks like. Despite the fact that the UK put them in their place in the 1982 war, Argentina has decided to attempt to re-assert sovereignty over the islands.
lots of oil.
The latest moves by Argentina involve declaring a maritime exclusion zone- a step short of blockade. The have started requiring permits for any and all vessels that wish to sail in the waters of the Falklands.
They have also started boarding vessels that are carrying anything that can be used for oil drilling and detaining them. This includes stopping the British Flagged Thor Leader, which was stopped and detained for carrying a load of pipes.
There are also reports that the Argentine Air Force is shadowing the movements of the US owned, but Panama Flagged oil rig Ocean Guardian as it is being moved to the Falklands to begin drilling. Currently (as of the time of this writing) the Ocean Guardian is still listed as enroute to the Falklands.
Estimates are that there could be an oil field of 60 billion barrels around the Falklands. The North Sea field so far has produced 40 billion barrels.
Argentina is having financial difficulties. They have $13 billion of foreign loans due. Argentina "tore up" an agreement to share oil finds off the Falklands with the UK. For Argentina they want all, and for the UK to have nothing.