Scientists have concluded that meteorites that bombarded our planet contributed to enriching its atmosphere with oxygen, after a study they conducted on a meteorite crater.
Specialists from the Korea Institute of Geoscience and Mineral Resources reported in the journal Communications Earth & Environment the discovery of stromatolites in the Hapcheon Basin, the only confirmed meteorite crater on the Korean Peninsula.
Researchers believe that stromatolites formed in a hydrothermal lake created after an asteroid impact. The heat from the molten rock formed by the impact likely maintained a high water temperature for an extended period and saturated it with minerals, creating ideal conditions for microbial growth.
Stromatolites are among the oldest known evidence of life on Earth. They were formed by microorganisms, particularly cyanobacteria, which produce oxygen during photosynthesis. Stromatolite fossils are estimated to be at least 3.5 billion years old.
Scientists have identified several stromatolites in the northwestern part of the Haptsion crater. Each stromatolite is approximately 10–20 centimeters in diameter . This is the first discovery of its kind in the crater.
The findings lead us to reconsider the so-called "Great Oxidation Event," the sharp increase in oxygen concentration in Earth's atmosphere approximately 2.4 billion years ago. The researchers hypothesize that hydrothermal lakes of impact (meteorite) origin may have served as local hotspots (or, as they metaphorically termed them in the article, "oxygen oases") where oxygen-producing microbes flourished.
Geochemical analysis of the stromatolites revealed traces of extraterrestrial material (more than 0.02%), as well as of the surrounding parent rock, and evidence of high-temperature water impact. Hydrothermal fingerprints were most pronounced in the structures' inner layers, suggesting they formed at a much hotter, earlier stage.
All of this data supports the hypothesis that stromatolites evolved in a hydrothermal lake that gradually cooled inside a meteorite crater.
