Rocks made of barium sulfate (called barytic rocks) from the Pilbara Craton in Western Australia. Credit: Gerhard Hundertmark
To learn more about our planet’s earliest organisms, researchers must analyze rocks from early Earth. They can only be found in a few places on the Earth’s surface. The Pilbara Craton in Western Australia is one such rare site; There we find rocks around 3.5 billion years old containing traces of the microorganisms that lived at that time.
A research team led by the University of Göttingen has discovered new clues about the formation and composition of this ancient biomass, providing insight into Earth’s earliest ecosystems. The results are published in the journal Precambrian research.
Using high-resolution techniques such as nuclear magnetic resonance (NMR) spectroscopy and nearby X-ray absorption fine structure (NEXAFS), researchers analyzed carbonaceous particles found in rocks made of sulfate of barium. This allowed scientists to obtain important information about the structure of microscopically small particles and show that they are of biological origin. It is likely that the particles were deposited as sediment in the water body of a “caldera”, a large cauldron-shaped hollow that forms after volcanic activity.
Additionally, some particles must have been transported and modified by hydrothermal waters just below the volcano’s surface. This indicates a turbulent history of sediment deposition. By analyzing different carbon isotopes, the researchers concluded that different types of microorganisms were already living near the volcanic activity, similar to those found today in Iceland’s geysers or in the park’s hot springs. Yellowstone National Park.
The study not only sheds light on Earth’s past, but is also interesting from a methodological point of view. First author Lena Weimann, from the Center for Geosciences at the University of Göttingen, explains: “It was very exciting to be able to combine a range of techniques at high resolution, which allowed us to obtain insights into the history of the deposition of organic particles and their origin. As our findings show, original traces of the first organisms can still be found, even from extremely old materials. »
More information:
L. Weimann et al, Carbonaceous matter in ∼3.5 Ga black-bed barite from the Dresser Formation (Pilbara Craton, Western Australia) — Insights into the organic cycle on juvenile Earth, Precambrian research (2024). DOI: 10.1016/j.precamres.2024.107321
Provided by the University of Göttingen
Quote: High-resolution techniques reveal clues in 3.5 billion year old biomass (February 21, 2024) recovered on February 21, 2024 from
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