https://phys.org/news/2020-03-blocks-life-earth-thought-billion-year-old.html Building blocks for life on Earth arrived much later than we thought, billion-year-old rocks show: 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. extract: "If you combine this with the evidence for very ancient life on Earth, it reveals that life got started on our planet surprisingly quickly, within only a few hundred million years. Now this might sound like a lot of time, and it is, but it is far different from what we used to think, that life took half a billion, or even a billion years to get started. "And this gives hope for finding life on other planets that had a shorter geological history and period of 'warm and wet' conditions than Earth, because if life could get started quickly here, then perhaps it got started quickly elsewhere." Professor Dr. Carsten Münker, also at the University of Cologne, added: "The fact that we are still finding traces of rare platinum metals in the Earth's mantle means that we can assume they were only added after the formation of the core was completed—they were certainly the result of later collisions of the Earth with asteroids or smaller planetesimals." more at link..... the paper: https://www.nature.com/articles/s41586-020-2069-3 Ruthenium isotope vestige of Earth’s pre-late-veneer mantle preserved in Archaean rocks: Abstract: The accretion of volatile-rich material from the outer Solar System represents a crucial prerequisite for Earth to develop oceans and become a habitable planet1,2,3,4. However, the timing of this accretion remains controversial5,6,7,8. It has been proposed that volatile elements were added to Earth by the late accretion of a late veneer consisting of carbonaceous-chondrite-like material after core formation had ceased6,9,10. This view could not be reconciled with the ruthenium (Ru) isotope composition of carbonaceous chondrites5,11, which is distinct from that of the modern mantle12, or of any known meteorite group5. As a possible solution, Earth’s pre-late-veneer mantle could already have contained a fraction of Ru that was not fully extracted by core formation13. The presence of such pre-late-veneer Ru can only be established if its isotope composition is distinct from that of the modern mantle. Here we report the first high-precision, mass-independent Ru isotope compositions for Eoarchaean ultramafic rocks from southwest Greenland, which display a relative 100Ru excess of 22 parts per million compared with the modern mantle value. This 100Ru excess indicates that the source of the Eoarchaean rocks already contained a substantial fraction of Ru before the accretion of the late veneer. By 3.7 billion years ago, the mantle beneath southwest Greenland had not yet fully equilibrated with late accreted material. Otherwise, no Ru isotopic difference relative to the modern mantle would be observed. If constraints from other highly siderophile elements besides Ru are also considered14, the composition of the modern mantle can only be reconciled if the late veneer contained substantial amounts of carbonaceous-chondrite-like materials with their characteristic 100Ru deficits. These data therefore relax previous constraints on the late veneer and are consistent with volatile-rich material from the outer Solar System being delivered to Earth during late accretion.