공룡 및 고생물학 관련 전문 용어 1개
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The Cretaceous–Paleogene (K-Pg) extinction event is a mass extinction that occurred approximately 66 million years ago at the boundary between the Cretaceous and Paleogene periods. It is the most recent of the geological 'Big Five' mass extinctions. The primary cause was the impact of an asteroid roughly 10 km in diameter that struck what is now the Yucatán Peninsula of Mexico, forming the approximately 180–200 km wide Chicxulub crater. The impact ejected vast quantities of dust, soot, and sulfate aerosols into the stratosphere, triggering an 'impact winter' that blocked sunlight, shut down photosynthesis, and collapsed food chains globally. Approximately 75% of all species on Earth perished, including all non-avian dinosaurs, pterosaurs, most marine reptiles, ammonites, and many groups of marine invertebrates. Simultaneously, the extinction created vast empty ecological niches that catalyzed the adaptive radiation of mammals and birds, ultimately establishing the ecological foundations of the Cenozoic Era.