The Macquarie Island

Very beautiful and amazing Island is Macquarie. Macquarie Island is an oceanic Island in the Southern Ocean of Australia. It is lying 1500 km south-east of Tasmania and approximately halfway between Australia and the Antarctic continent.

The Island is the lay bared form into a crest of the undersea Macquarie Ridge, raised to it is present position where the Indo-Australian tectonic plate meets the Pacific plate. Macquarie Island is a site of major geo-conservation significance, being the only place where rocks from the Earth’s mantle are being actively lay bared above sea level.

                                        Macquarie Island- More pictures

It is the only island in the world composed completely of oceanic crust and rocks from the Earth’s mantle deep below the surface.

Macquarie Island most likely began as a spreading ridge under the sea with the formation of new oceanic crust somewhere between 11 million and 30 million years ago.

At some stage the spreading halted and the crust began to narrow, compressing rock’s upward from deep within the mantle. As the ridge grew it finally became exposed above the ocean surface about 600000 years ago.

Since Macquarie Island emerged, it has chiefly been carved by marine processes such as wave action, unlike other sub Antarctic islands, which have been shaped by glaciers. These unique exposures include wonderful examples of pillow basalts and other extrusive rocks.

The chief landscape feature is a central rolling plateau 250-300 m above sea level, bounded on all sides by steep cliffs, from the foot of which extends a coastal platform up to 800 m wide. Glacial tendency up to 20 m thick covers much of the plateau and there are several lakes.

The original elephant seal population of about 100000 animals was subdued by 70% as a result of these operations. The visitors also brought exotic mammals and caused the extermination of two endemic subspecies of land birds.

There are no permanent human resident on Macquarie Island although the Australian Antarctic Division station is occupied all year round. The only access to the island is by sea and there are no harbors or landing facilities, so ship-traffic in the area is maximum.