Chromatography Uncovers Organic Molecules in 3.5-Billion-Year-Old Rocks

Organic molecules and gases have been found in rocks that have been dated at 3.5 billion years old. The rock formations in Australia are thought to be some of the oldest rocks found on Earth. One of the widely accepted hypotheses for how life on earth began, states that it began with organic molecules acting as building blocks and precursors for more advanced molecules.

The work is reported in a paper - Ingredients for microbial life preserved in 3.5-billion-year-old fluid inclusions – published in the journal Nature Communications. The study, according to a press release from the University of Cologne, shows that solutions from archaic hydrothermal vents contained essential components that formed a basis for the earliest life on our planet. Read on to see how chromatography played a key role in finding the key ingredients for life on Earth.

Barites help start life

The German research team examined rocks known as barites from the Dresser Formation in Western Australia. Barites are minerals composed of barium sulphate and is often found in sandstones and limestones as void filling crystals. The barite dates from when the rocks were formed about 3.5 billion years ago, when life started forming on earth. Dr. Helge Mißbach, lead author on the paper states:

In the field, the barites are directly associated with fossilized microbial mats, and they smell like rotten eggs when freshly scratched. Thus, we suspected that they contained organic material that might have served as nutrients for early microbial life.

Scientists have long believed that organic molecules could act as substrates for microbes to attach and use as metabolic processes developed, but there has been scant evidence for these processes so far. The researchers examined the barite inclusions as they are a chemically stable mineral and could have kept ancient organic molecules and gases preserved, again Dr. Mißbach: We suspected that these inclusions contained simple organic molecules that might have served as nutrients for early microbial life.

Gas chromatography taps into primordial life

The team used a variety of analytical tools including gas chromatography-mass spectrometry to examine the barite inclusions. Find more information about GC in the article Gas Chromatography Troubleshooting Part 1 – Peak Shape Issues. In the barite inclusions, the team found organic molecules including acetic acid and methanethiol. These molecules could have acted as substrates for metabolic processes of early microbial life.

“The immediate connection between primordial molecules emerging from the subsurface and the microbial organisms – 3.5 billion years ago – is a striking finding that greatly adds to our still fragmentary understanding of the earliest evolution of life on Earth" Mißbach concluded. These molecules could be key agents in the origin of life on Earth.