Australia

History

The past. Sahul: with the sea about 120 metres lower, Australia, New Guinea and Tasmania were one continent, and more than two million square kilometres of today’s shallow seas were dry land, from the plains of the Gulf of Carpentaria, where a lake grew larger than Tasmania, to the land bridge across Bass Strait. Sahul was already whole when the timeline begins; the rising sea drowned most of it between 14,676 and 8,076 years ago. The lines that stand for the sea turn halfway to the colour of land, all at once, and only across those spans.

4.4 billion years ago

Zircon crystals formed that are among the oldest known pieces of Earth; they survive in younger rocks on this plate.

136 million years ago

A new ocean ridge began to split India away from this plate's western edge.

83.5 million years ago

After a long rift, Australia broke away from Antarctica.

83 million years ago

The Tasman Sea began to open as the Lord Howe Rise drifted away from Australia.

51.5 million years ago

A major reorganization of plate motions changed how Australia and Antarctica moved apart.

16 million years ago

This part of the Indian Ocean floor began to press slowly against India, and a wide zone between them began to buckle.

8 million years ago

The squeeze doubled in speed, and the ocean floor between this plate and India folded into long waves.

6 million years ago

The northern edge of the Australian continent began to jam into the volcanic arc to its north, pushing up Timor.

6 million years ago

Far south of New Zealand, the Macquarie part of this plate began to move on its own as a small rigid plate.

Sources: Williams et al. 2018, Quaternary Science Reviews 182:144; Reeves et al. 2013, Quaternary Science Reviews 74:97 · Wilde et al. 2001, Nature 409:175 · Gibbons, Whittaker and Muller 2013, Journal of Geophysical Research 118:808 · Williams, Whittaker and Muller 2011, Tectonics 30:TC6012 · Gaina et al. 1998, Journal of Geophysical Research 103:12413 · Whittaker et al. 2007, Science 318:83 · Bull et al. 2010, Geology 38:307 · Royer and Gordon 1997, Science 277:1268 · Cochran 1990, Proceedings ODP Scientific Results 116 · Harris 2011, in Arc-Continent Collision (Springer) p.163 · Cande and Stock 2004, Geophysical Journal International 157:399