An international research team has discovered evidence of the earliest forms of fresh water on Earth in the Jack Hills region of Western Australia, dating back to 4 billion years ago, only about half a billion years after the creation of the planet, thanks to zircon crystals, according to “Nature Geoscience” article published on Monday.
Zircon age is one of the most significant techniques for determining the age of rocks and minerals. It involves examining a compound known as quaternary zirconium silicate, which is typically found alongside trace quantities of rare elements, such as uranium and thorium.
The quaternary zirconium silicate compound is a material characterized by its high chemical stability, which makes it resistant to decomposition and weathering, besides, its contents of uranium and thorium isotopes decompose into lead isotopes over time, and this process follows the laws of radioactive decomposition, where the age of the zircon can be calculated based on the ratio between uranium and lead in it, and consequently the age of the rocks and their components.
The research team was able to study oxygen isotopes in small crystals of quaternary zirconium silicate and found signatures of 4 billion-year-old light oxygen isotopes, which are usually created by hot freshwater that changes the composition of rocks several kilometers below the Earth’s surface.
The finding not only provides insight into Earth’s early past but also implies that land masses and freshwater prepared the path for life to develop relatively quickly after the planet’s birth, according to an official press release from Curtin University in Australia