Building Blocks for Life on Earth Arrived Later Than We Thought

The rocks the team analysed are the oldest preserved mantle rocks. They allow us to see into the early history of the Earth as if through a window. (Image: UNSW)
The rocks the team analysed are the oldest preserved mantle rocks. They allow us to see into the early history of the Earth as if through a window. (Image: UNSW)

Ancient rocks from Greenland have shown that the elements necessary for the evolution of life did not come to Earth until very late in the planet’s formation — much later than previously thought. An international team of geologists — led by the University of Cologne and involving UNSW scientists — have published important new findings about the origin of oceans and life on Earth: They have found evidence that a large proportion of the elements that are essential to the formation of oceans and life — such as water, carbon, and nitrogen — only came to Earth very late in its history.

The geological investigations published today have shown that most of the water only came to Earth when its formation was almost complete. (Image: UNSW)

The geological investigations published today have shown that most of the water only came to Earth when its formation was almost complete. (Image: UNSW)

Many scientists previously believed that these elements had already been there at the beginning of our planet’s formation. However, the geological investigations published in the prestigious journal Nature have shown that most of the water in fact only came to Earth when its formation was almost complete.

Some of the authors of the paper, from left to right: Professor Martin Van Kranendonk (UNSW), Associate Professor Allen Nutman (University of Wollongong), Professor Vickie Bennett (ANU). (Image: UNSW)

Some of the authors of the paper, from left to right: Professor Martin Van Kranendonk (UNSW), Associate Professor Allen Nutman (University of Wollongong), Professor Vickie Bennett (ANU). (Image: UNSW)

Volatile elements such as water originate from asteroids, the planetary building blocks that formed in the outer solar system. There has been a lot of discussion and controversy in the scientific community around when precisely these building blocks came to Earth. Dr. Mario Fischer-Gödde from the Institute of Geology and Mineralogy at the University of Cologne, who led the work, says we are now able to narrow down the timeframe more precisely:

To understand the temporal process, the researchers determined the isotope abundances of a very rare platinum metal called ruthenium, which the Archean mantle of the Earth contained. Like a genetic fingerprint, the rare platinum metal is an indicator for the late growth phase of the Earth. Professor Fischer-Gödde said:

Professor Martin Van Kranendonk, the UNSW scientist who was part of the research, says the reason why this is of such interest relates directly to understanding the origins of life on Earth, how we humans came to be, and in fact, to whether we might be alone, or have neighbors in the universe, adding:

Professor Dr. Carsten Münker, also at the University of Cologne, added:

Scientists refer to the very late building blocks of the Earth, which arrived through these collisions, as the “late veneer.” Professor Fischer-Gödde said:

Provided by: University of New South Wales [Note: Materials may be edited for content and length.]

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