Astonishing Fossil Site Reveals Mammal's Recovery After The Last Great Mass Extinction

By Stephen Luntz
24 OCT 2019, 19:00

An extraordinary fossil location has revealed the speed of evolution after the extinction of the non-avian dinosaurs. Within 100,000 years the number of mammalian species represented at a Colorado site more than doubled, and larger-bodied creatures appeared over the next million years. No previous site has recorded the aftermath of a mass extinction in anything like such detail.

An estimated 75 percent of all the species on the planet went extinct in the aftermath of the asteroid strike that caused the Chicxulub crater. Ash and sulfur dioxide cleared from the skies within a few years, but the ocean acid-alkaline balance took 80,000 years to return to normal, and temperatures even longer. For the survivors, the world was rich in newly opened ecological niches.

Inevitably, this led to a great expansion of species, with mammals, birds and flowering plants being among the greatest beneficiaries. Until now, we have lacked a detailed record of the process, however, particularly one with a clear timeline. That is just what Dr Tyler Larson Of the Denver Museum of Nature and Science and co-authors have described in Science.

At Corral Bluffs, just outside Colorado Springs, a single outcrop reveals the last hundred thousand years of the Cretaceous (K) and first million years of the Paleogene (Pg) era without the discontinuities seen elsewhere. Thousands of fossils outstandingly presevered within egg-shaped structures called concretions have already been recovered. Moreover, the site is layered with volcanic ash that can be accurately dated, giving us precise measurements on when its 150 stratigraphic layers were deposited.

More:
https://www.iflscience.com/plants-and-animals/astonishing-fossil-site-reveals-mammals-recovery-after-the-last-great-mass-extinction/