A team of researchers from The University of Western Australia and the University of Cambridge has made a remarkable discovery that could shed light on the origin and early evolution of life on Earth.
They have found evidence of ancient hydrothermal vent sediments that date back to 3.5 billion years ago, when the planet was still young and hostile to most forms of life.
A New Discovery in the Pilbara Region(Photo : Dan Meyers/Unsplash)
The sediments, which are composed of iron-rich clay minerals called greenalite and calcium phosphate minerals called apatite, were found in the North Pole Dome area west of Marble Bar in the Pilbara region of Western Australia.
This area is known for hosting some of the oldest and best-preserved rocks on Earth, including the famous stromatolites, which are fossilized microbial mats that are considered to be the earliest signs of life.
The researchers examined the sediments using high-resolution electron microscopes and geochemical modeling, and published their findings in the journal Science Advances.
They were surprised to find that the greenalite and apatite particles were much more abundant than the iron-oxide particles that give the rocks their bright red color.
They also found that the greenalite and apatite formed when hot fluids from hydrothermal vents mixed with seawater on the ancient seafloor.
The discovery of these ancient hydrothermal vent sediments has important implications for the origin of life, as they provide clues about the environmental conditions and the biochemical processes that were occurring billions of years ago.
One of the key elements for life is phosphorus, which is essential for the formation of DNA, RNA, and other biomolecules.
However, phosphorus is scarce in the modern ocean, and its availability may have been a limiting factor for the emergence and diversification of life.
The researchers found that the apatite particles in the sediments contained high concentrations of phosphorus, and that the phosphorus was likely released from the oceanic crust as it reacted with the heated seawater.
This suggests that hydrothermal vents may have been a source of phosphorus for life on early Earth.
Another important factor for life is the availability of energy, which is needed to drive the chemical reactions that sustain living systems.
The researchers found that the greenalite particles in the sediments were highly reactive, and that they could have acted as catalysts for the synthesis of organic molecules from simple inorganic compounds.
This could have been a way for life to harness the energy from the hydrothermal vents, which are known to be rich in chemical and thermal gradients.
The researchers also speculated that the greenalite and apatite particles could have served as templates or scaffolds for the assembly of organic molecules, or even as primitive cell membranes or compartments.
These particles could have provided a suitable environment for the emergence of self-replicating systems, which are the basis of life.
The study suggests that hydrothermal vents, which probably littered the seafloor soon after the first oceans formed about 4.2 billion years ago, were not only a source of phosphorus and energy, but also of tiny, highly reactive clay particles that could have played a role in the origin and early evolution of life.
These particles are essentially hidden in plain sight, and are only observable using very high magnification electron microscopes.
The researchers hope that their discovery will inspire further investigations into the ancient hydrothermal vent sediments, and that they will reveal more secrets about the enigmatic past of our planet and the origin of life.