Rocks about 3.5 billion years ago are confirmed to be ``the traces of the oldest life on earth'', and the possibility of being useful for life exploration on Mars

An international research team that examined rocks about 3.48 billion years ago found in the Dresser Formation in Western Australia concluded that 'this rock is derived from the activity of life.' This is the oldest trace of life on Earth, and it may be useful for life exploration on Mars.

Advanced two- and three-dimensional insights into Earth's oldest stromatolites (ca. 3.5 Ga): Prospects for the search for life on Mars | Geology | GeoScienceWorld

Earth's Oldest Stromatolites and the Search for Life on Mars

3.5 billion-year-old rock structures are one of the oldest signs of life on Earth | Live Science

Stromatolites , which are rocks formed by the accumulation of dead cyanobacteria and mud, have been found to be more than 3 billion years old, so they are called the ``oldest traces of life''. increase. However, too old stromatolites lose traces of chemical organic matter due to diagenesis and weathering, so it is controversial whether the rocks are really of biological origin or due to geological movement.

Stromatolites are not only found as fossils, but also exist in some water areas on Earth at the time of writing. Below is a photograph of existing stromatolites in Hamelin Bay , off the coast of Western Australia.


Mark, Vicki, Ellaura and Mason

Until now, the oldest stromatolites accepted by the scientific community are 3.43 billion years old, but in the year 2000, in the Dresser Formation of Western Australia, stromalites dated to 3.48 billion years ago. A rock believed to be trite has been discovered.

So a research team led by Keyron Hickman-Lewis of the Natural History Museum in London , in collaboration with the French National Center for Scientific Research (CNRS) , used high-resolution 2D and 3D imaging techniques to study rocks 3.48 billion years old. I investigated.

As a result of the investigation, uneven layers including small dome-shaped layers were confirmed in the rock. This is because the blue-green algae that form stromatolites perform photosynthesis, so the growth rate differs between places that are exposed to sunlight and those that are not. evidence to show. In addition, a typical columnar structure seen in modern stromatolites was also confirmed.

'The layers formed by the microbes are uneven in thickness, wrinkled and rise and fall on very small spatial scales,' said Linda Kah , a geoscientist at the University of Tennessee who was not involved in the study. Layers tend to be formed.' `` Considering these, we can find the characteristics of the layer of microorganisms, '' he told the scientific media Live Science.

In 2016, rocks that are believed to be stromatolites 3.7 billion years ago were discovered, but it is said that no conclusion has been reached as to whether or not these rocks are really of biological origin.

A fossil that is said to be the ``oldest trace of life in the world'' 3.7 billion years ago is discovered-GIGAZINE

The results of this research may be useful not only for the study of early life on Earth, but also for the search for life on Mars. Stromatolites in the Dresser Formation are covered with iron oxide, which is produced by the reaction between iron in rocks and the atmosphere, making it difficult to find traces of organic matter. Similarly, rocks on the surface of Mars are also affected by oxidation in a wide range, so it is difficult to find traces of organic matter.

However, the research team argues that it may be possible to search for traces of life in samples brought back from Mars by applying the method of analyzing the rocks of the Dresser Formation this time.

in Science,   Creature, Posted by log1h_ik