Visitors Now:
Total Visits:
Total Stories:
Profile image
By Alton Parrish (Reporter)
Contributor profile | More stories
Story Views

Now:
Last Hour:
Last 24 Hours:
Total:

Life Began on Land 300 Million Years Earlier Than Previously Believed

Wednesday, November 9, 2016 15:49
% of readers think this story is Fact. Add your two cents.

(Before It's News)

Earth formed about 4.5 billion years ago and there is evidence that life appeared more 4 billion years ago in the ocean. In 2015, “remains of biotic life” were found in 4.1 billion-year-old rocks in Western Australia. The similarities between all present-day organisms indicate the presence of a common ancestor from which all known species have diverged through the process of evolution. 

Life took hold on land at least as early as 3.2 billion years ago, suggests a study by scientists from Berlin, Potsdam and Jena (Germany).  

The team. led by Sami Nabhan of the Freie Universität Berlin. studied ancient rock formations from South Africa’s Barberton greenstone belt. These rocks are some of the oldest known on Earth, with their formation dating back to 3.5 billion years.

In a layer that has been dated at 3.22 billion years old, tiny grains of the iron sulfide mineral pyrite were discovered that show telltale signs of microbial activity. These signs are recorded both in trace element distributions as well as in the ratio between the sulfur isotopes 34S and 32S in the pyrite.

The Barberton Mountains in northeastern South Africa are covered by rocky grasslands; these hills are made of some of the oldest rocks on Earth (3.2 – 3.5 billion years old). 
B4INREMOTE-aHR0cHM6Ly8xLmJwLmJsb2dzcG90LmNvbS8tMklUZWt1UFJ4bnMvV0NPYTRkejlldkkvQUFBQUFBQUJRUTAvV2J1dDMycXdRRFE3SFl4Q3VkZFREQl81SE9OdDdCOE1BQ0xjQi9zNjQwL25ld3NpbWFnZS5qcGc=
Credit: Sami Nabhan/FSU Jena)
Using instrumentation installed in Potsdam in 2013, the scientists showed that the fraction of 34S in the core of some crystals differ characteristically from that of the same crystal’s rim, indicating that the exterior of the grain involved a processing of sulfur by microbes, so-called biogenic fractionation. The determination of the 34S/32S ratio, using sample masses less than one billionth of a gram, was carried out at the GFZ German Research Centre for Geosciences by Michael Wiedenbeck of the GFZ’s secondary ion mass spectrometry (SIMS) lab.

The composition of the rock, the shape of the crystals, and the layering visible in the field all indicate that the studied rock sequence was derived from an ancient soil profile; this so-called paleosol developed on a river flood plain 3.22 billion years ago. Field data collected during this study imply that a braided river system transported the sediment containing the iron sulfide crystals. It is interpreted that microbes living in the soil, at a level that was continually shifting between wet and dry conditions, subsequently produced the rim overgrowths on the pyrite crystals.

Based on this evidence, the scientists conclude in their publication in the journal “Geology” that they found evidence for biological activity on land at this very early date. Their research pushes back the date for the oldest evidence of life on land to some 300 million years earlier than previously documented.

Some researchers believe that since life arose relatively quickly on Earth that it could be common in the universe.
Contacts and sources:
GFZ German Research Centre for Geosciences
Citation: Sami Nabhan, Michael Wiedenbeck, Ralf Milke and Christoph Heubeck: Biogenic overgrowth on detrital pyrite in ca. 3.2 Ga Archean paleosols. In: Geology, vol. 44, No. 9 (DOI: 10.1130/G38090.1)

Report abuse

Comments

Your Comments
Question   Razz  Sad   Evil  Exclaim  Smile  Redface  Biggrin  Surprised  Eek   Confused   Cool  LOL   Mad   Twisted  Rolleyes   Wink  Idea  Arrow  Neutral  Cry   Mr. Green

Total 1 comment
  • Science can “suggest” away till its hearts content but what can they prove?

    This study sure doesn’t prove when life began.

    At least the scientists were honest unlike this BIN headline!

Top Stories
Recent Stories

Register

Newsletter

Email this story
Email this story

If you really want to ban this commenter, please write down the reason:

If you really want to disable all recommended stories, click on OK button. After that, you will be redirect to your options page.