MSGID: 1:317/3 63d4a4f7   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Meteorites reveal likely origin of Earth's volatile chemicals    
      
     Date:   
         January 27, 2023   
     Source:   
         Imperial College London   
     Summary:   
         By analyzing meteorites, researchers have uncovered the likely   
         far-flung origin of Earth's volatile chemicals, some of which form   
         the building blocks of life.   
      
      
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   FULL STORY   
   ==========================================================================   
   By analysing meteorites, Imperial researchers have uncovered the likely   
   far- flung origin of Earth's volatile chemicals, some of which form the   
   building blocks of life.   
      
      
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   They found that around half the Earth's inventory of the volatile   
   element zinc came from asteroids originating in the outer Solar System   
   -- the part beyond the asteroid belt that includes the planets Jupiter,   
   Saturn, and Uranus. This material is also expected to have supplied   
   other important volatiles such as water.   
      
   Volatiles are elements or compounds that change from solid or liquid   
   state into vapour at relatively low temperatures. They include the six   
   most common elements found in living organisms, as well as water. As such,   
   the addition of this material will have been important for the emergence   
   of life on Earth.   
      
   Prior to this, researchers thought that most of Earth's volatiles came   
   from asteroids that formed closer to the Earth. The findings reveal   
   important clues about how Earth came to harbour the special conditions   
   needed to sustain life.   
      
   Senior author Professor Mark Rehka?mper, of Imperial College London's   
   Department of Earth Science and Engineering, said: "Our data show that   
   about half of Earth's zinc inventory was delivered by material from the   
   outer Solar System, beyond the orbit of Jupiter. Based on current models   
   of early Solar System development, this was completely unexpected."   
   Previous research suggested that the Earth formed almost exclusively   
   from inner Solar System material, which researchers inferred was the   
   predominant source of Earth's volatile chemicals. In contrast, the   
   new findings suggest the outer Solar System played a bigger role than   
   previously thought.   
      
   Professor Rehka?mper added: "This contribution of outer Solar System   
   material played a vital role in establishing the Earth's inventory   
   of volatile chemicals. It looks as though without the contribution of   
   outer Solar System material, the Earth would have a much lower amount   
   of volatiles than we know it today -- making it drier and potentially   
   unable to nourish and sustain life."  The findings are published today   
   in Science.   
      
   To carry out the study, the researchers examined 18 meteorites of varying   
   origins -- eleven from the inner Solar System, known as non-carbonaceous   
   meteorites, and seven from the outer Solar System, known as carbonaceous   
   meteorites.   
      
   For each meteorite they measured the relative abundances of the five   
   different forms -- or isotopes -- of zinc. They then compared each   
   isotopic fingerprint with Earth samples to estimate how much each of these   
   materials contributed to the Earth's zinc inventory. The results suggest   
   that while the Earth only incorporated about ten per cent of its mass from   
   carbonaceous bodies, this material supplied about half of Earth's zinc.   
      
   The researchers say that material with a high concentration of zinc and   
   other volatile constituents is also likely to be relatively abundant in   
   water, giving clues about the origin of Earth's water.   
      
   First author on the paper Rayssa Martins, PhD candidate at the Department   
   of Earth Science and Engineering, said: "We've long known that some   
   carbonaceous material was added to the Earth, but our findings suggest   
   that this material played a key role in establishing our budget of   
   volatile elements, some of which are essential for life to flourish."   
   Next the researchers will analyse rocks from Mars, which harboured water   
   4.1 to 3 billion years ago before drying up, and the Moon. Professor   
   Rehka?mper said: "The widely held theory is that the Moon formed when   
   a huge asteroid smashed into an embryonic Earth about 4.5 billion   
   years ago. Analysing zinc isotopes in moon rocks will help us to test   
   this hypothesis and determine whether the colliding asteroid played an   
   important part in delivering volatiles, including water, to the Earth."   
   This work was funded by the Science and Technology Facilities Council   
   (STFC - - part of UKRI) and Rayssa Martins is funded by an Imperial   
   College London Presidents' PhD Scholarship.   
      
       * RELATED_TOPICS   
             o Matter_&_Energy   
                   # Solar_Energy # Materials_Science # Nature_of_Water   
             o Earth_&_Climate   
                   # Earth_Science # Near-Earth_Object_Impacts # Geology   
             o Fossils_&_Ruins   
                   # Origin_of_Life # Early_Climate # Fossils   
       * RELATED_TERMS   
             o Recent_single-origin_hypothesis o Timeline_of_evolution o   
             Amino_acid o Water o Earth o Dead_zone_(ecology) o Fullerene   
             o Gravitation   
      
   ==========================================================================   
   Story Source: Materials provided by Imperial_College_London. Original   
   written by Caroline Brogan. Note: Content may be edited for style   
   and length.   
      
      
   ==========================================================================   
   Journal Reference:   
      1. Rayssa Martins, Sven Kuthning, Barry J. Coles, Katharina Kreissig,   
      Mark   
         Rehka"mper. Nucleosynthetic isotope anomalies of zinc in meteorites   
         constrain the origin of Earth's volatiles. Science, 2023; 379   
         (6630): 369 DOI: 10.1126/science.abn1021   
   ==========================================================================   
      
   Link to news story:   
   https://www.sciencedaily.com/releases/2023/01/230127131132.htm   
      
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