About Extinction
About 66 million years ago, a mass extinction ended the age of non-avian dinosaurs. The strongest evidence points to a giant asteroid impact near what is now the Yucatán Peninsula, with additional environmental stress from large volcanic eruptions and long-term climate changes.
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The K-Pg Boundary
A thin layer of rock marks the transition between the Cretaceous and Paleogene periods.
Learn MoreChicxulub Impact
A huge asteroid struck near the present-day Yucatán Peninsula.
Learn MoreImmediate Effects
The impact caused regional devastation and worldwide disturbances.
Learn MoreImpact Winter
Dust, soot, and sulfur compounds reduced sunlight.
Learn MoreDeccan Volcanism
Massive eruptions were also occurring in India around the same time.
Learn MoreWho Survived
Small size, flexible diets, sheltering behavior, and access to detritus may have helped some groups survive.
Learn MoreBirds Survived
Birds are the dinosaur lineage that crossed the extinction boundary.
Learn MoreLife After the Extinction
Ecosystems recovered over millions of years.
Learn MoreThe K-Pg Boundary
Around the world, this boundary contains unusual amounts of iridium, an element rare in Earth's crust but more common in asteroids. It also contains shocked minerals and tiny glassy particles formed during extreme impact conditions.
Chicxulub Impact
The buried Chicxulub crater is roughly 180 kilometers wide. Geophysical mapping, drilled rock cores, impact minerals, and dating all connect the crater to the end-Cretaceous event.
Immediate Effects
The collision released enormous energy, triggering earthquakes, tsunamis, wildfires in some regions, and ejecting material high into the atmosphere. Effects differed by distance from the impact site.
Impact Winter
When sunlight dropped, photosynthesis slowed dramatically. Plants and plankton at the base of food webs declined. Global temperatures changed rapidly, placing severe stress on ecosystems.
Deccan Volcanism
The Deccan Traps released huge volumes of lava and gases over an extended period. Scientists continue to study how much these eruptions contributed to climate stress before and after the asteroid impact.
Who Survived
Crocodilians, turtles, mammals, amphibians, some fish, insects, and several bird lineages survived. Survival patterns were complex and differed between land, freshwater, and marine ecosystems.
Birds Survived
Not all ancient bird groups survived, but several lineages did. Modern birds later diversified into thousands of species, carrying dinosaur ancestry into the present.
Life After the Extinction
With giant non-avian dinosaurs gone, mammals and birds expanded into many ecological roles. Forests returned, marine food webs rebuilt, and the Cenozoic Era developed a very different mix of life.