Springtime for Chicxulub

Using markers on fishbones like tree rings, scientists have determined that the Chicxulub asteroid impact occurred during springtime in the Northern Hemisphere.

IMAGE: An asteroid impact off the coast of Mexico about 66 million years ago triggered devastating flooding at a site in North Dakota (illustrated). That dino-killing strike took place in the spring, a study suggests. CREDIT: Joschua Knüppe

It’s turning toward spring here in North America, and a few bulbs are doing their best to bud through the mud and snow enjoyed by a lot of our team. Spring: It’s a time for renewal, for birth, and, according to new research appearing in Nature, spring is a time for mass extinction.

Scientists are continuing to learn everything they can about arguably the worst day in Earth’s history — the day the dinosaurs died. And this new science result started off a little strange — that day was in the springtime. No, really. That is the result of this research, which was published last week and led by vertebrate paleontologist Melanie During.

Scientists studying sedimentary rocks and fossils at the amazing Tanis site in southwestern North Dakota analyzed the bones of paddlefish and sturgeons to try and determine what time of year the Chicxulub impact occurred. Today I learned that fishbones, like trees, contain the marks of cyclical evidence for growth patterns. Vigorous growth shows up as thick bands, while slower growth makes for thinner bands, and times of drought or famine show up as a line of…