The Age of Dominican Amber

摘要

Despite the scientific and lay popularity of fossiliferous amber from the Dominican Republic, there is confusion over its age(s). The commonly cited Eocene age (ca. 40 million years old [Ma]) for this amber comes from a study of the maturation of exomethylene resonance using ~(13)C NMR. The data and conclusions of that study are critiqued here. The best evidence for ages of Dominican resinites comes from ~(14)C dating (of very young eastern deposits) and, for the much older amber, from stratigraphy based on previous studies of Foraminifera and calcareous nannofossils. At least some of the eastern deposits are probably only several hundred to several thousand years old, and those from the northern mountains yield "true" amber [e.g., crosslinked, highly polymerized resinite] that varies in age from lower Miocene to mid Oligocene (23-30 Ma). In addition, the phylogenetic position of insects preserved in Dominican and Baltic ambers shows Dominican taxa to be relatively younger than the 40 Ma Baltic fossils. All evidence indicates that Dominican amber is considerably younger than the highly popularized age of 40 Ma.