These markings are clearly features of some sort of an ancient hexagon structure, which probably is the dome of a larger structure of building buried beneath the ice sheet and probably part of an underground ancient city. The dome is about 45 meters in diameter with visible walls of 8 meters high.
There are many artificial objects, structures and figures around the dome, a possible man-made entrance to the underground city and what looks like a military base or port in front of the dome, suggesting that the military and scientists already know this location which could mean that they are secretly exploring the underground city.
Click image to see the structure/dome in 1280×720 HD.
A quote taken from the book ‘The Lost City of Antarctica, Civilizations of the Ancient World’ reads as follows: