Scientists have discovered levels of iridium 30 times greater than average in the Cretaceous/Tertiary (KT) boundary, the layer of sedimentary rock laid down at the time of the dinosaur extinction.

layer—the geologic boundary zone that seems to cap any known rock layers containing dinosaur fossils. Iridium is relatively rare in Earth's crust but is more abundant in stony meteorites ...

Hammond’s fascination and desire to revive dinosaurs backfires when many ... scientists developed this idea due to high amounts of iridium in the K-Pg layer of the geological boundary zone ...

Geologist Keller debuts with a scathing and illuminating examination of scientific research into what caused the demise of the dinosaurs ... the mass extinction, and the iridium layer attributed ...

The rock and sediment there had a similar composition to the iridium layers ... the early Jurassic, … the dinosaurs really took off.” Deeper in time, a mass extinction event that ended ...

Hammond's fascination and desire to revive dinosaurs backfires when many ... scientists developed this idea due to high amounts of iridium in the K-Pg layer of the geological boundary zone where ...