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2026-08-02 06:14 UTC → 2026-08-02 19:09 UTC ·
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In July 2026 an international team used high‑precision nickel‑isotope measurements of the global Cretaceous‑Paleogene clay layer Recent work continues to identify refine the picture of the Chicxulub impactor event as a rare Ornans‑class CO‑class carbonaceous chondrite (CO). The ~10–15 km asteroid struck a shallow sea above present‑day Yucatán, vaporising rock, generating a megatsunami and impact that generated a powerful blast wave. Because planet‑wide firestorm followed by an impact winter. High‑precision nickel‑isotope analyses confirmed the impactor’s CO chondrites contain very nature and its low volatiles, researchers argued volatile content, implying that the primary extinction driver was a massive plume of fine dust lofted into the atmosphere was the primary extinction driver, first trapping heat and then blocking sunlight. Subsequent work by Purdue University and the University of Colorado, published in *Journal of Geophysical Research: Biogeosciences*, modeled rather than sulfur‑driven cooling. Modeling studies described the plume as micrometre‑scale dust and sugar‑grain‑sized spherules that remained aloft for years. Calculations indicate the dust acted as years, creating an insulating lid, raising lid that raised surface temperatures to roughly 3.5 times baseline and delivering a thermal dose doses about 17 times lethal for humans, enough sufficient to ignite worldwide global wildfires within one to two hours and cause rapid loss of much terrestrial fauna. The same dust later formed an “impact winter” that blocked sunlight for months to years. Later on hours. A new international study led by Purdue University planetary scientist Brandon C. Johnson (JGR Biogeosciences, 31 July 2026, 2026) reinforces this scenario, emphasizing a *Science Advances* paper reinforced the CO classification via global nickel‑isotope data and emphasized the low sulfur, carbon and water content of CO chondrites, arguing previously under‑appreciated silicate dust layer formed from vaporized rock. The authors argue that the this dust cloud—not sulfur‑driven cooling—was the main cause of the impact winter. A Purdue‑led study on the same day quantified blanket amplified the heat‑trapping effect, estimating heat pulse, driving a 3.5‑fold temperature increase and lethal radiation doses, supporting rapid, planet‑wide firestorm that likely caused the rapid fire‑storm scenario as a primary driver abrupt loss of ~75 % of species, including most non‑avian dinosaurs, before the mass extinction. dust‑laden atmosphere produced a prolonged impact winter.