Researchers from the University of Göttingen are using high resolution techniques to trace the origin and composition of a 3.5 billion-year-old biomass.
The Pilbara Craton in Western Australia is one of the few places on earth where traces of the first organisms can be found.
The craton is an ancient Archaean crust with a date range from between 3.8–2.7 Ga (billion years ago), that may have once been part of the Vaalbara supercontinent or the continent of Ur.
A new study, published in the journal Precambrian Research, has analysed barium sulphate (known as barite rocks) from an area within the canton known as the Dresser Formation.
The Dresser Formation belongs to the lower part of the Warrawoona Group and is exposed in the North Pole Dome in Western Australia. It comprises a variety of lithologies, including metavolcanic and metasedimentary rocks and hydrothermal deposit
Using nuclear magnetic resonance spectroscopy (NMR) and near-edge X-ray Absorption Fine Structure (NEXAFS), the researchers identified microscopically small particles in the rock samples which are traces of microbial life.
The study suggests that the particles were likely deposited as sediment in the waters within an ancient caldera, while some must have been transported and changed by hydrothermal waters in areas of volcanic activity.
By analysing various carbon isotopes, the researchers concluded that different types of microorganisms were already living in the vicinity of the volcanic activity, similar to those found today at Icelandic geysers or at hot springs in Yellowstone National Park.
Lena Weimann, Göttingen University’s Geosciences Centre, said: “It was very exciting to be able to combine a range of high-resolution techniques, which enabled us to derive information about the history of how the organic particles were deposited and their origin. As our findings show, original traces of the first organisms can still be found even from extremely old material.”
Header Image Credit : University of Göttingen
Sources : University of Göttingen – Weimann, L. et al. Carbonaceous matter in ~3.5 Ga black bedded barite from the Dresser Formation (Pilbara Craton, Western Australia) – insights into organic cycling on the juvenile Earth. Precambrian Research (2024). DOI: 10.1016/j.precamres.2024.107321
