💥 THE K-PG BOUNDARY: A LINE IN THE ROCK
PAGE 1 OF 5 — A LINE IN THE ROCK
66 MA
THE GLOBAL MURDER SCENE
A thin grey line of iridium appears in rock layers on every continent. Below it lie Tyrannosaurus, Triceratops, duck-billed hadrosaurs, ammonites, and palm forests, a bustling Cretaceous world frozen in stone. Above the line: silence. No more giant non-avian dinosaurs. Scientists call this razor-thin band the K-Pg boundary, the instant the Mesozoic Era ended, about 66 million years ago. The layer is sometimes only a few centimetres thick, yet it is the most famous murder scene in the history of life.
🔬 THE CLUE IN THE ROCK
🔬 Iridium is common in asteroids but rare in Earth's crust
🌍 The spike appears worldwide at the same depth
📖 Walter Alvarez proposed the impact story in 1980
🌍 The spike appears worldwide at the same depth
📖 Walter Alvarez proposed the impact story in 1980
"One grey line, the whole story of the end."
LINE!
BELOW
🦕 Land dinosaurs of every shape
🦈 Mosasaurs and plesiosaurs ruled seas
🌿 Warm forests from pole to pole
🦈 Mosasaurs and plesiosaurs ruled seas
🌿 Warm forests from pole to pole
ABOVE
💀 Non-avian dinosaurs vanish completely
🐦 Small birds are the dinosaur survivors
🐊 Crocs, turtles, and fish pull through
🐦 Small birds are the dinosaur survivors
🐊 Crocs, turtles, and fish pull through