A greenhouse world where dinosaurs and flowering plants flourished together. It ended with the Chicxulub asteroid impact (K-Pg extinction) that wiped out non-avian dinosaurs.
Explore the Cretaceous Earth in 3D →Find Seoul’s past position on a 3D Earth. Compare today with 66 million years ago, then move time yourself to follow the land.
Compare Seoul’s land today and in the past →Clear early flowering-plant fossils appear in the Early Cretaceous, around 140–130 million years ago. Their actual origin may be older: fossil and DNA analyses yield different dates, with a 2026 study favouring the latest Jurassic. The timing remains debated.
Between about 130 and 100 million years ago, flowering plants diversified rapidly, with new ecological opportunities for insects. Their rise was not simultaneous everywhere: dominance of vegetation developed unevenly and continued into the Cenozoic. Pollination was part of this changing web of relationships, not a single proven cause of the radiation.
Around 94 million years ago, Oceanic Anoxic Event 2 expanded oxygen-poor waters and left organic-rich sediments in a warm world. Volcanism and nutrient cycling are leading explanations; the event does not mean every ocean became completely oxygen-free at once.
Around 90 million years ago, a shallow seaway covered parts of central North America. At extensive stages, it linked Arctic waters with the Gulf of Mexico and separated western and eastern land areas. Its shorelines repeatedly advanced and retreated; marine fossils remain in rocks such as Colorado’s Mancos Shale.