In order to recognize the first organisms on our planet, scientists have to analyze the rocks of the early Earth, and these can only be found in a few places on the Earth’s surface: scientists found them in areas of Australia.
He Pilbara Craton in Western Australia is one of those rare places where extremely old Earth rocks are found. There they are found rocks about 3.5 billion years old what contain the remains of microorganisms who lived at that time.
Microorganisms from 3.5 billion years ago
This was discovered by a research team led by the University of Göttingen new clues about the origin and composition of this ancient biomasswhich provides information about the first ecosystems from the ground. The results are published in the journal Precambrian research.
Using high-resolution techniques such as nuclear magnetic resonance spectroscopy (NMR) and X-ray absorption fine structure (NEXAFS), The scientists analyzed the carbonaceous particles found in barium sulfate rocks. This allowed scientists to obtain important information about structure of microscopically small particles and prove that they are of biological origin. The particles were likely deposited as sediment in a water body called a “caldera,” a large cauldron-shaped hole that forms after volcanic activity.
In addition, some particles had to be transported and transformed hydrothermal waters just below the surface of the volcano. This indicates a turbulent history of sediment deposition. By analyzing different isotopes of carbon, the scientists came to a conclusion Various types of microorganisms already lived near the volcanic activitysimilar to those found today in Iceland’s geysers or the hot springs of Yellowstone National Park.
The study sheds light not only on the Earth’s past, but is also interesting from a methodological point of view. first author, Lena Weimannováfrom the Center for Geosciences at the University of Göttingen, explains: “It was very exciting that we could combine different high-resolution techniques, allowing us to infer information about the depositional history of organic particles and their origin. As our findings show, the original traces of the first organisms can still be found even in extremely old materials.“.
Link
L. Weimann et al., Carbon mass in ∼3.5 Ga black barite from the Dresser Formation (Pilbara Craton, Western Australia) – Insights into organic cycling on a juvenile Earth, Precambrian Research (2024). DOI: 10.1016/j.precamres.2024.107321
https://phys.org/news/2024-02-high-resolution-techniques-reveal-clues.html
