Dec 12 2013
Amber is a rock that began as tree resin. When it was resin it collected pollen, flecks of dirt, plants, small creatures, and other debris as it flowed from the tree. The amber above contains a spider, air bubbles, dirt and an ant, all preserved when the resin hardened.
Scientists are fascinated by amber because everything inside it is as old as the rock. This year an international team led by Ralf Tappert of the University of Innsbruck analyzed carbon-12 and carbon-13 in present-day tree resin and amber dating all the way back to the Triassic period. They chose amber for their chemical analysis because, as Tappert explains, “Compared to other organic matter, amber has the advantage that it remains chemically and isotopically almost unchanged over long periods of geological time.”
From 538 samples they calculated the concentration of oxygen in the atmosphere for 220 million years of the Earth’s history. Surprisingly, they learned that the concentration in the early Cretaceous period was only 10-15% compared to 21% oxygen today. The dinosaurs had less oxygen to breathe than we do!
This finding tossed out at least one theory about the dinosaurs, namely that their size was possible because they had so much more oxygen to breathe. Oops! They had less.
Click here to read more about the study at ABC Science (Australia).
Ancient air tells the tale.
(photo from Wikimedia Commons. Click on the image to see the original)