Heard and McDonald Islands

Heard Island (Eddie 2541/Flickr, CC BY-NC 2.0).

Australian external territory of Heard and McDonald Islands lies in a remote, stormy Southern Ocean, near the meeting-point of Antarctic and temperate Indian Ocean sector about 1,500 km north of Antarctica and over 4,000 km south-west of Australia.

As the only volcanically active subantarctic islands they 'open a window into the Earth', providing the opportunity to observe ongoing geomorphic processes and glacial dynamics.

The distinctive conservation value of one of world's rare pristine island ecosystems lies in the complete absence of alien plants and animals, with undisturbed habitat for sub-antarctic plants and animal.

Heard Island’s Mawson Peak is the summit of Big Ben, an active, towering volcano that dominates the group, with a thick mantle of snow and glacial ice contrasting black volcanic rocks in a startling array of forms and shapes, with continuous activity clearly evident from observations of minor steam and smoke emissions.

The winds above Southern Ocean in these latitudes create unique weather patterns when they come up against the enormous Big Ben, including spectacular cloud formations around the summit and unbelievably rapid changes in winds, cloud cover and precipitation.

McDonald Island, 43.5km west of Heard Island, is the major island in its group, which includes Flat Island and Meyer Rock, consists of two distinct parts joined by a narrow central isthmus and are home to seals, flying birds and penguins.

Other extraordinary landforms include: McDonald Island Cape Pillar flute; Meyer Rock lonely pinnacle; northern Heard Island peninsulas caves and lava formations; Mawson Peak smoking caldera; McDonald Island western sea cliffs; Nullarbor Plain shifting sands; and extensive, dynamically changing Spit.

It is the only subantarctic island that is invaluable for having an intact set of interrelated ecosystems; terrestrial, freshwater, coastal and marine, in which the ongoing evolution of plants and animals occur in natural state.