(ORDO NEWS) — The study of rocks and rock formations can give us new data about when life did begin on Earth.
In the search for the oldest traces of life on Earth, scientists are helped by stomatolites – fossil remains of cyanobacterial mats.
Stromatolites, which are billions of years old, are scattered all over the world. They are composed of layered or finely layered rocks, which can be formed either as a result of mineralized layers of microbial matting or as a result of non-living chemical reactions between the rock and the environment.
So far, 3.43 billion year old stromatolites from Western Australia, the Strelli Pool Formation, are the oldest generally accepted traces of life on Earth. Now modern geologists from all over the world have re-examined the 3.48 billion year old stromatolites from the Western Australian Dresser Formation.
So, according to the latest data, life on Earth originated 3.5 billion years ago!
They used several methods to study the two- and three-dimensional microstructures present in Dresser’s stromatolites, including optical microscopy, Raman spectroscopy, scanning electron microscopy, inductively coupled plasma mass spectrometry with laser ablation (ICP-MS), and laboratory and synchrotron computer tomography.
None of these tests revealed microfossils or organic materials, but they showed structures and characteristics consistent with the biological origin of the stone.
Once upon a time, stromatolites were photosynthetic microbial mats that thrived at the bottom of a shallow sea lagoon. As the sediment settled on the mats, the microbes were pushed up, away from the sediment and into the sunlight, forming dome-like structures that resemble cups in an egg carton.
The team of researchers also found pillar-like formations that form in rocks as a result of microbial growth. As the scientists emphasized, they were the result of the movement of organisms towards sunlight, the researchers say. Small voids in the rock correspond to the degassing or drying of decaying organic material.
“These stromatolites, found in the stratigraphically lower sedimentary horizons of the Dresser Formation, are the oldest direct evidence for the existence of life on Earth,” the article says .
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