Now, a new discovery in South Korea suggests that the asteroid<\/a> effect may have been even more complex than we realized.<\/p>\n Beneath a crater gouged by a massive impact around 42,000 years ago<\/a>, a team led by geologist Jaesoo Lim of the Korea Institute of Geoscience and Mineral Resources (KIGAM) has identified several stromatolites.<\/p>\n Stromatolites are layered structures built by microbial mats, similar to some of the oldest known evidence of life on Earth.<\/p>\n This discovery suggests that the heat generated by the impact may have created a long-lasting hydrothermal environment similar to hot springs, where microbial communities could thrive.<\/p>\n It’s possible that during the era of heavy bombardment, billions of years ago, impact craters like these may have created countless temporary refuges for early life across the young Earth.<\/p>\n The story of life’s origins is a murky one; it remains unclear exactly when and how non-living components came together in a way that triggered the processes that define biology.<\/p>\n One major clue, however, can be found in stromatolites<\/a>.<\/p>\n In several places around the world, these structures \u2013 the layered mineral scaffolding built by microbes such as cyanobacteria and other microorganisms, similar to the calcium-carbonate bones of corals \u2013 have been found dating back as far as 3.5 billion years ago<\/a>.<\/p>\n That’s some of the oldest evidence for life<\/a> our planet has proffered.<\/p>\n But there’s a lot we don’t know about how these communities emerged and spread. Figuring that out is sort of like trying to mentally picture a 1,000-piece puzzle with only seven pieces.<\/p>\n The Jeokjung-Chogye Basin in Hapcheon may have just added another handful of pieces by contextualizing discoveries linked to impact craters such as Chicxulub<\/a>, where evidence of microbial mats<\/a> had been interpreted as material swept into the crater rather than communities that formed there naturally.<\/p>\n Although the basin is a well-known bowl-shaped feature in the landscape of the Korean peninsula, its identity as an impact structure wasn’t known until relatively recently, as revealed in a 2021 paper<\/a>.<\/p>\n Subsequent analyses showed the mineral signatures<\/a> of meteoritic material merging with the terrestrial material in the basin, reverse-engineered its shape<\/a> to understand how the impact took place, used radiocarbon techniques<\/a> to figure out when it formed, and determined that it once held a vast body of water<\/a>.<\/p>\n Now, digging under the northwestern part of the crater, Lim and his colleagues found multiple stromatolites, measuring between 10 and 20 centimeters (4 to 8 inches) in diameter.<\/p>\n It has already been established that an impact crater can shatter and heat Earth’s crust where it falls, creating a system where the slowly dissipating residual heat warms water that fills the basin left behind \u2013 a hydrothermal impact lake.<\/p>\n These stromatolites, the researchers found, probably formed in just such an environment.<\/p>\n The team analyzed their mineral content and found traces of an element called europium that becomes dramatically more soluble in hot hydrothermal fluids.<\/p>\n Europium is usually interpreted as a signature of past hydrothermal activity; it represents a strong signal suggesting the lake that once filled the Jeokjung-Chogye Basin was hydrothermal in nature.<\/p>\n Other signatures support this interpretation, such as high levels of calcium, calcite, and sulfur associated with microbes adapted to hot environments<\/a>, which were found in the sediment.<\/p>\n The stromatolites, radiocarbon dating of one sample suggested, formed between about 23,400 and 14,600\u2009years ago. That indicates that the hydrothermal lake was present for a few tens of millennia.<\/p>\n It also offers a snapshot into how early Earth may have been primed for life.<\/p>\n The finding shows that an asteroid impact can accidentally create the perfect spa retreat for microbes.<\/p>\n If early Earth was heavily cratered by asteroid impacts during the early bombardment before the inner Solar System settled down, it could have hosted many such havens.<\/p>\n And here’s where it gets even more interesting.<\/p>\n Early Earth did not have a lot of oxygen<\/a> before about 2.4 billion years ago. Scientists think the rise of the first photosynthetic lifeforms, such as cyanobacteria, was at least partially responsible for the air we now breathe today<\/a>.<\/p>\n There’s also evidence to suggest<\/a> that oxygen may have been a byproduct of the microbial metabolism that built stromatolites.<\/p>\n If that’s the case, early bombardment may have created pockets of oxygen production worldwide \u2013 what the researchers call “oxygen oases”.<\/p>\n “This is the first comprehensive evidence suggesting that stromatolites could form in hydrothermal lakes created by asteroid impacts,” Lim says<\/a>. “Such environments may have provided favorable conditions for early microbial ecosystems.”<\/p>\n Related: Colossal Impact 3 Billion Years Ago May Have Boosted Life on Earth<\/a><\/p>\n This is a little interpretive \u2013 the current data are far from proof of what role, if any, stromatolites played in Earth’s oxygenation.<\/p>\n But the discovery does further indicate that life on Earth may have arisen through a combination of relatively rare ingredients and events we have yet to find anywhere else in the Universe.<\/p>\n Other impact craters on Earth need to be investigated closely to determine whether stromatolite-rich hydrothermal lakes may have contributed to the rise of oxygen in Earth’s atmosphere.<\/p>\n Further, this result suggests that there is still hope to find similar signatures elsewhere. Impact craters on Mars<\/a>, for example, may be harboring the buried remains of stromatolites, yet to be uncovered.<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/hapcheon-crater.jpg\")
A view of the crater. (KIGAM)<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/hapcheon-impact.jpg\")
A diagram illustrating how the impact may have created the conditions for stromatolite growth. (Lim et al., Commun. Earth Environ<\/a>., 2026)<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/basin-map.jpg\")
A map of the Jeokjung-Chogye Basin, with the studied sites marked. (Lim et al., Commun. Earth Environ<\/a>., 2026)<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/electron-backscattering.jpg\")
The team used electron backscattering to study the mineral composition of the stromatolites. (Lim et al., Commun. Earth Environ<\/a>., 2026)<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/stromatolite-radiocarbon.jpg\")
Some of the stromatolites under preparation for radiocarbon dating. (Lim et al., Commun. Earth Environ<\/a>., 2026)<\/p>\n![\"Subscribe](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2026\/05\/1779408609_365_FOMO-1200x628-_Dont-miss-the-next-breakthrough_-cosmic-colourful-642x336.jpg\")
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