UFO?
No, tall radio antenna array with six wired tether, in the Western Australia's Badgingarra National Park.
There is a ground-level enclosure. It has a fence around it, thus the wildlife and cattle cannot get in and graze, so the vegetation grows better there, and the ground is not disturbed, and so it appears darker than the surrounding terrain.
The triangular shape mirrors the outline of the six wires (the bright spots are where the wires are anchored to the ground)
SOURCE
NOTE: this one is not THE antenna, but an example of what one can see in Australia.