Solving Antarctic fossil mystery reinforces climate change concerns

Washington Post : How fossilized marine diatoms ended up on top of a mountain range in Antarctica has long puzzled scientists. The fossils date from the Pliocene era, about 2 million to 5 million years ago. When the fossils were first discovered in 1984, two theories were proposed. The so-called dynamicists said that the melting of the East Antarctic Ice Sheet (EAIS) raised ocean levels and that isostatic uplift caused new landmasses to rise; the combination caused the diatoms to be transported from the seafloor to the mountaintops. The stabilists countered that the ice sheet did not change; instead, powerful winds blew the diatoms from the ocean into the mountains. According to a new study by Reed Scherer of Northern Illinois University and his colleagues, what actually happened was a combination of both: The EAIS did retreat, but not as far as previously thought, and winds carried the diatoms the rest of the way. Besides solving the diatom mystery, the study also points up the vulnerability of the EAIS to global warming and raises concerns as current atmospheric carbon levels approach those of the Pliocene.