Water, one of the most precious resources on Earth, has had its own story amid the formation and evolution of the planet. Scientists have now identified when Earth received its most precious resource.
Essential for life, researchers found water appeared on Earth about four billion years ago. This timeline is five hundred million years earlier than previously thought.
Researchers from Curtin University's School of Earth and Planetary Sciences and Khalifa University, UAE analysed ancient crystals from the Jack Hills in Western Australia’s Mid-West region. They examined the age and oxygen isotopes in tiny crystals of the mineral zircon.
Zircon crystals can survive geological processes like erosion and metamorphism, making them valuable in geological studies. They are often used in radiometric dating to determine the age of rocks, as zircon can contain trace amounts of uranium and thorium.
The team was able to date the hydrological cycle, which is the continuous process through which water moves around Earth and is crucial for sustaining ecosystems and supporting life on our planet.
What they found was unusually light isotopic signatures as far back as four billion years ago. Such light oxygen isotopes are typically the result of hot, fresh water-altering rocks several kilometres below Earth’s surface.
Study co-author Dr Hugo Olierook, from Curtin University’s School of Earth and Planetary Sciences, said the discovery was crucial for understanding how Earth formed and how life emerged.
“This discovery not only sheds light on Earth’s early history but also suggests landmasses and freshwater set the stage for life to flourish within a relatively short time frame – less than 600 million years after the planet formed,” Dr Olierook said.
Evidence of freshwater deep inside Earth challenges the existing theory that Earth was completely covered by ocean four billion years ago. The findings mark a significant step forward in our understanding of Earth’s early history and open doors for further exploration into the origins of life.
