Fresh water on Earth appeared earlier than we thought, study finds

Curtin University's Dr. Hugo Olierook with a rock from the Jack Hills in Western Australia, which contained the zircon crystals analyzed in this research. Credit: Curtin University.

New research led by Curtin University has discovered that fresh water, essential for life, appeared on Earth about 4 billion years ago.

This is 500 million years earlier than previously believed.

The study, titled “Onset of the Earth’s hydrological cycle four billion years ago or earlier,” was published in the journal Nature Geoscience.

The lead author, Dr. Hamed Gamaleldien, an Adjunct Research Fellow at Curtin’s School of Earth and Planetary Sciences and an Assistant Professor at Khalifa University in the UAE, explained that the team analyzed ancient crystals from the Jack Hills in Western Australia’s Mid West region.

This analysis has pushed back the timeline for the emergence of fresh water to just a few hundred million years after Earth’s formation.

Dr. Gamaleldien said, “We were able to date the origins of the hydrological cycle, which is the continuous process where water moves around Earth and is crucial for supporting life and ecosystems on our planet.”

The researchers examined the age and oxygen isotopes in tiny crystals of the mineral zircon. They found unusually light isotopic signatures dating back 4 billion years.

These light oxygen isotopes are typically the result of hot, fresh water altering rocks deep below Earth’s surface.

“Evidence of fresh water this deep inside Earth challenges the existing theory that Earth was completely covered by ocean 4 billion years ago,” Dr. Gamaleldien added.

Dr. Hugo Olierook, a co-author of the study from Curtin University’s School of Earth and Planetary Sciences, emphasized the importance of this discovery for understanding how Earth formed and how life emerged.

“This discovery not only sheds light on Earth’s early history but also suggests that landmasses and fresh water provided the conditions for life to develop relatively quickly—within less than 600 million years after the planet formed,” Dr. Olierook said.

The findings represent a significant step forward in our understanding of Earth’s early history and open new opportunities for exploring the origins of life.

The research team is part of the Earth Dynamics Research Group and the Timescales of Mineral Systems Group at Curtin’s School of Earth and Planetary Sciences and the John de Laeter Center. Part of the research was conducted using the CAMECA 1300HR3 instrument at the John de Laeter Center’s Large Geometry Ion Microprobe (LGIM) facility.

This groundbreaking study helps us understand the early conditions of our planet and provides new insights into how life could have started on Earth.