By CHRISTINA LARSON, Related Press
Scientists have lengthy debated whether or not dinosaurs had been in decline earlier than an asteroid smacked the Earth 66 million years in the past, inflicting mass extinction.
New analysis suggests dinosaur populations had been nonetheless thriving in North America earlier than the asteroid strike, however it’s just one piece of the worldwide image, unbiased specialists say.
“Dinosaurs had been fairly various and now we all know there have been fairly distinct communities” roaming round earlier than being abruptly worn out, stated Daniel Peppe, a examine co-author and paleontologist at Baylor College.
The newest proof comes from analyzing a portion of the Kirtland Formation in northern New Mexico that’s been recognized for round 100 years to comprise a number of attention-grabbing dinosaur fossils.
Scientists now say these fossils and the encircling rocks date from round 400,000 years earlier than the asteroid struck, which is taken into account a brief interval in geologic time. The age was decided by analyzing small particles of volcanic glass inside sandstone and by learning the route of magnetic minerals inside mudstone of the rock formation.
The outcomes present “the animals deposited right here will need to have been dwelling near the top of the Cretaceous,” the final dinosaur period, stated Peppe.
The findings had been printed Thursday within the journal Science.
Variations between the dinosaur species present in New Mexico and people discovered at a web site in Montana that had been beforehand dated to the identical timeframe “run counter to the concept that dinosaurs had been in decline,” he stated.
The fossils beforehand discovered on the New Mexico web site embrace Tyrannosaurus rex, an enormous, long-necked dinosaur, and a Triceratops-like horned herbivore.
Scientists who weren’t concerned within the examine cautioned that proof discovered at a single location won’t level to a broader pattern.
“This new proof about these very late-surviving dinosaurs in New Mexico could be very thrilling,” stated College of Bristol paleontologist Mike Benton, who was not concerned within the examine. However he added, “This is only one location, not a illustration of the complexity of dinosaur faunas on the time throughout North America or all around the world.”
Though scientists have discovered dinosaur fossils on each continent, precisely courting them could be a problem, stated paleontologist and examine co-author Andrew Flynn of New Mexico State College. Simply datable materials comparable to carbon doesn’t survive in fossils, so scientists should search for surrounding rocks with exact traits that can be utilized to find out ages.
Additional analysis would possibly assist full the image of what vary of dinosaur species was alive globally on the eve of the asteroid crash, stated Flynn.
The Related Press Well being and Science Division receives assist from the Howard Hughes Medical Institute’s Division of Science Schooling and the Robert Wooden Johnson Basis. The AP is solely accountable for all content material.
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