The ancient, nutrient-poor landscape that holds the secrets of Earth's earliest life
Beneath the vast deserts and iron ore mines of Western Australia lies a geological relic. This territory contains some of the oldest rocks on the planet, potentially preserving evidence of life from over three billion years ago, all within a landscape shaped by extreme erosion and ancient supercontinents.
The geological foundation of Western Australia is remarkably ancient. The Pilbara and Yilgarn cratons are remnants of Ur, a supercontinent that existed between 3 and 3.2 billion years ago. In May 2017, researchers identified mineral deposits in the Pilbara craton, such as 3.48-billion-year-old geyserite, which may represent the earliest known evidence of terrestrial life.
This extreme antiquity has created a landscape of profound stability and erosion. Because the only significant mountain-building event since the rifting from Antarctica was the formation of the Stirling Range, the terrain is largely a low plateau. Most of the state sits at an average elevation of 400 metres, with no part exceeding 1,249 metres at Mount Meharry.
However, this geological age comes at a biological cost. The intense erosion has left the soils remarkably infertile, often lacking essential nutrients like phosphorus, nitrogen, and zinc. While this has forced local flora to adapt to extreme poverty in the soil, it has also made the region's agriculture heavily dependent on fertilizers. This dependency, alongside land clearing, has impacted local biodiversity and contributed to issues like dryland salinity in the Wheatbelt.
Despite these harsh conditions, the state is a global biodiversity hotspot. The southwest corner, characterized by a Mediterranean climate and the Leeuwin Current, supports an extraordinary density of plant and marine species. This includes the Jarrah-Karri forests and some of the world's most southerly coral reefs, proving that even the most nutrient-depleted soils can host complex, thriving ecosystems.
Source: Western Australia
