Analysis of gases in fossil amber

Fossilized tree resin, commonly known as amber, has long served as a robust source of paleobiologic information via the preservation of embalmed invertebrates. Another more radical idea is that gas bubbles enclosed in fossil amber may represent ancient air trapped at the time the original resin was exuded from its host tree. Alternatively, gas trapped in ancient amber may instead represent contamination by modern air. Here, we analyze gaseous inclusions from ambers sampled worldwide spanning the Cretaceous, Eocene, Eocene-Oligocene, Eocene-Miocene, U. Oligocene-Miocene, and modern. After careful consideration of a number of possible explanations, we suggest the gas inclusions may represent, at least in part, ancient air.