In a breakthrough study that could reshape our understanding of abrupt climate change events, researchers have identified geochemical evidence pointing to a cosmic encounter approximately 12,800 years ago. This event, linked to the onset of the Younger Dryas, a sudden and severe global cooling period, may have been triggered by Earth passing through debris from a disintegrating comet. Published in the open-access journal PLOS One, the study led by Christopher Moore from the University of South Carolina culminates years of detailed analysis of seafloor sediments from Baffin Bay near Greenland, presenting compelling, though not definitive, signs of extraterrestrial material embedded within the oceanic layers dating to that period.
The Younger Dryas event represents one of the most dramatic climate reversals in the last glacial period, with temperatures plunging by roughly 10 degrees Celsius over the span of about a year, and conditions remaining cold for over a millennium. For decades, the prevailing explanation has centered around freshwater influx from glacial meltwaters disrupting crucial Atlantic Ocean currents that transport warm tropical waters northward, resulting in climatic cooling. However, the Younger Dryas Impact Hypothesis, a controversial alternative, proposes that widespread impacts and atmospheric shockwaves from cometary debris destabilized ice sheets and instigated massive meltwater runoff, prompting a domino effect that shut down ocean circulation and mechanistically drove the rapid cooling.
Despite its appeal, the impact hypothesis has been challenged by the scarcity of rigorous ocean sedimentary evidence supporting such a cosmic collision. To fill this gap, Moore and his interdisciplinary team conducted an intensive geochemical survey of four deep marine sediment cores extracted from Baffin Bay. These cores, their stratigraphy verified through radiocarbon dating, encompassed sediment layers deposited precisely during the early phase of the Younger Dryas cooling interval. Utilizing advanced analytical techniques such as scanning electron microscopy (SEM), single-particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOF-MS), energy dispersive spectroscopy (EDS), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), the researchers meticulously characterized minute particles embedded within the sediment matrix.
One of the most striking findings was the identification of metallic debris whose elemental composition aligns closely with cometary dust profiles known from prior extraterrestrial studies. These metallic particles co-occurred with a diverse array of microspherules—tiny spherical beads formed by high-temperature processes—some predominantly terrestrial in composition but with a subset bearing signatures indicative of extraterrestrial origin. The presence of elements such as iron (Fe), silicon (Si), sulfur (S), chromium (Cr), nickel (Ni), cobalt (Co), and notably platinum (Pt) in nanoparticulate forms within the same sedimentary layers is highly suggestive of cosmic matter deposition triggered by energetic atmospheric events, possibly linked to comet fragment airbursts or impacts.
The morphology of these particles, observed through SEM, revealed unique textures and folded edges on metallic dust particles, consistent with rapid melting and quenching processes expected during high-energy atmospheric entry or impact scenarios. Notably, some microspherules contained complex elemental assemblages, including FeSi, FeS, and FeCr phases, implying multi-stage thermal alteration involving terrestrial and extraterrestrial materials melting and mixing. Furthermore, elevated concentrations of platinum group elements such as platinum and iridium—classic hallmarks of extraterrestrial inputs—were recorded, reinforcing the hypothesis that Earth’s surface received a geochemical anomaly of cosmic origin at this critical juncture.
Although these findings strongly indicate the existence of a distinct Younger Dryas impact layer within marine sediments, the authors exercise scientific caution, emphasizing that while the data align with the impact model, they stop short of conclusively proving it. The geochemical anomaly observed coincides temporally with the onset of abrupt cooling but requires further corroboration through expanded core analyses, higher-resolution dating, and refined particle characterization to definitively establish a causative link between a cometary encounter and the Younger Dryas climate shift.
Dr. Christopher Moore highlights the significance of ocean sediments as valuable archives of extraterrestrial events, noting that their work underlines an oceanic record of the Younger Dryas event that had remained largely unexplored. The study pioneers the deployment of cutting-edge nano-analytical methodologies to marine sediment cores, enabling unprecedented detection of submicron-sized extraterrestrial particles that may have escaped notice in prior studies focused on terrestrial records such as ice cores, lake sediments, or archaeological strata.
Dr. Mohammed Baalousha, contributing expertise in nano-scale analysis, underscores the novelty and utility of applying sophisticated instruments like spICP-TOF-MS and LA-ICP-MS to investigate nanoparticles formed or transported during purported cosmic events. Their ability to disentangle complex elemental signatures embedded within sediment layers expands the toolkit of climate scientists and geochemists seeking to track correlates of sudden environmental perturbations in geological records.
Adding crucial geological and geo-chemical insights, Dr. Vladimir Tselmovich contextualizes the broader implications of cometary impacts, citing historical instances where Earth’s encounters with comet fragments precipitated catastrophic environmental changes and societal upheavals. His detailed analysis of Baffin Bay microparticles confirms not only the presence of cometary matter in the region but also quantifies the atmospheric dust load sufficient to trigger a transient “impact winter.” This phenomenon likely precipitated the prominent cooling episode and prolonged climatic instability lasting over a millennium, lending support to the Younger Dryas Impact Hypothesis from a marine sediment perspective.
The study’s methodological rigor, which integrates multiple complementary analytical techniques, provides an intricate molecular and morphological fingerprint of extraterrestrial material preserved within ocean sediments. This multidisciplinary approach is pivotal for navigating the complex interplay of terrestrial and cosmic signatures within older sedimentary deposits altered by bioturbation, sediment reworking, and diagenetic processes that often obscure or dilute the extraterrestrial evidence.
Looking ahead, this research lays a firm foundation for future investigations targeting other geographically diverse marine cores to map the spatial extent and variability of the identified cosmic impact layer. Combining marine data with terrestrial archives promises to sharpen our understanding of how extraterrestrial events have influenced Earth’s climate history. Moreover, the findings encourage re-examination of sedimentary records from known rapid climate change periods for potential extraterrestrial markers previously overlooked.
While the debate over the Younger Dryas Impact Hypothesis continues, this new evidence marks a notable advancement by bridging the terrestrial-oceanic divide in impact research. Its implications extend beyond academic curiosity, informing models of abrupt climate forcing mechanisms relevant to understanding present and future climate system sensitivities. In an era when Earth’s climate faces unprecedented anthropogenic pressures, discerning the natural triggers of past drastic climate shifts remains critically important.
The research was facilitated by international collaboration among scientists spanning the United States, Russian Federation, United Kingdom, Czechia, and Australia. Support from academic institutions, national science foundations, and dedicated nonprofit groups like the Comet Research Group has been instrumental in propelling this intricate scientific inquiry. The combination of theoretical frameworks, cutting-edge analytical technologies, and access to well-preserved ocean sediment cores has enabled a nuanced exploration of humanity’s cosmic interactions etched deep within Earth’s geological record.
In conclusion, the discovery of a 12,800-year-old geochemical layer rich in cometary dust, microspherules, and unusual platinum anomalies in Baffin Bay sediments represents a significant milestone in comprehending the environmental aftermath of cosmic impacts. While not unequivocally resolving the Younger Dryas impact controversy, the unveiled sedimentary evidence adds a compelling piece to the complex puzzle of abrupt climate change, inviting renewed interdisciplinary efforts to decode Earth’s intertwined celestial and terrestrial history.
Article Title: A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay
News Publication Date: August 6, 2025
Web References: http://dx.doi.org/10.1371/journal.pone.0328347
Image Credits: Moore et al., 2025, PLOS One, CC-BY 4.0
Keywords: Younger Dryas, cometary dust, impact hypothesis, microspherules, platinum anomaly, Baffin Bay, marine sediments, geochemical analysis, scanning electron microscopy, inductively coupled plasma mass spectrometry, climate change, abrupt cooling
