Caption: The team analyzed amber samples from almost all well-known amber deposits worldwide. This amber originates from the Cretaceous period, an inclusion of foilage of the extinct conifer tree Parataxodium sp. from the Foremost Formation at Grassy Lake, Alberta, Canada. It is approximately 77 million years old. Photo credit: Ryan C. McKellar
An international team of researchers led by Ralf Tappert, University of Innsbruck, reconstructed the composition of the Earth's atmosphere of the last 220 million years by analyzing modern and fossil plant resins. The results suggest that atmospheric oxygen was considerably lower in the Earth's geological past than previously assumed. This new study questions some of the current theories about the evolution of climate and life, including the causes for the gigantism of dinosaurs. Scientists encounter big challenges when reconstructing atmospheric compositions in the Earth's geological past because of the lack of useable sample material. One of the few organic materials that may preserve reliable data of the Earth's geological history over millions of years are fossil resins (e.g. amber). "Compared to other organic matter, amber has the advantage that it remains chemically and isotopically almost unchanged over long periods of geological time," explains Ralf Tappert from the Institute of Mineralogy and Petrography at the University of Innsbruck.
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