Ancient asteroid craters may have been safe havens for Earth’s earliest oxygen-producing life.
Scientists in South Korea have uncovered evidence suggesting that asteroid impact craters may have played an important role in the rise of oxygen-producing life on early Earth.
A research team from the Korea Institute of Geoscience and Mineral Resources (KIGAM) discovered stromatolites inside the Hapcheon impact crater, the only confirmed asteroid impact crater on the Korean Peninsula. Stromatolites are layered rock formations formed by ancient microbial communities and are considered among the oldest known signs of life on Earth.
The findings were published in Communications Earth & Environment.
Hydrothermal Crater Lakes May Have Supported Early Microbes
Researchers believe the stromatolites formed in a hydrothermal lake that developed after a massive asteroid impact. Heat from molten rock produced during the collision likely kept the water warm and filled it with minerals for long periods, creating an environment where microbial life could thrive.
Stromatolites are commonly associated with cyanobacteria, microorganisms capable of producing oxygen through photosynthesis. Fossil records show these structures existed at least 3.5 billion years ago.
The team identified several stromatolites in the northwestern section of the Hapcheon crater. Each measured roughly 10 to 20 centimeters across. This is the first time stromatolites have been reported from the crater site.
New Insight Into Earth’s Great Oxidation Event
The discovery could help scientists better understand the Great Oxidation Event (GOE), which occurred around 2.4 billion years ago when oxygen levels in Earth’s atmosphere rose dramatically.
According to the researchers, hydrothermal lakes created by asteroid impacts may have served as protected habitats where oxygen-producing microbes flourished. These isolated environments may have acted as localized “oxygen oases” before oxygen became widespread across the planet.
Geochemical Evidence Points to Hot Water Activity
Chemical analysis of the stromatolites revealed traces linked to both extraterrestrial material and the surrounding bedrock. Researchers also found evidence that the formations had been altered by high-temperature water.
The innermost layers displayed stronger hydrothermal signatures, suggesting they formed during an earlier and hotter phase of the crater lake’s history.
Taken together, the evidence supports the idea that the stromatolites developed inside a post-impact hydrothermal lake that gradually cooled over time.
Possible Implications for Ancient Mars
The findings may also have relevance beyond Earth.
Scientists believe early Mars once contained impact craters filled with water. Because of this, the researchers suggest similar crater environments on Mars could be promising places to search for evidence of ancient microbial life.
Expanding on Earlier Hapcheon Crater Research
The new study builds on earlier work published in Gondwana Research in 2021, when KIGAM scientists first confirmed the existence of the Hapcheon impact crater.
The latest research adds possible biological evidence to the crater environment through the discovery of stromatolites and related geochemical signatures.
“This is the first comprehensive evidence suggesting that stromatolites could form in hydrothermal lakes created by asteroid impacts,” said Dr. Jaesoo Lim, lead author of the study. “Such environments may have provided favorable conditions for early microbial ecosystems.”
Reference: “Discovery of stromatolite formation in post-impact hydrothermal lacustrine environments and its implications for early Earth” by Jaesoo Lim, Youngeun Kim, Sujeong Park, Sangheon Yi, So-Jeong Kim, Gyujun Park, Young Hong Shin, Hang-Jae Lee, Gio An, Arum Jung, Sun Young Park, Donghoon Chung, Il-Mo Kang, Kyeong Ja Kim and Sung Won Kim, 14 April 2026, Communications Earth & Environment.
DOI: 10.1038/s43247-026-03206-7
The Korea Institute of Geoscience and Mineral Resources (KIGAM) is a government funded research institute focused on geoscience, natural resources, and Earth system research.
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