(Phys.org)—An international team of researchers has found evidence that suggests that Amazonia did not revert to savannah during the last ice age and instead remained forested. In their paper published in the journal Nature, the researchers describe how they retrieved stalagmite samples from a cave in one of the drier parts of Amazonia and used them to calculate not only how dry the area became during the last ice age, but what sorts of vegetation were growing. Mark Bush with the Florida Institute of Technology offers a News & Views piece in the same journal issue on the work done by the team and further explains how measuring the abundance of oxygen isotopes in stalagmites can reveal so much geological information.