May 5, 2012

Study Finds Humans, Mastodons, Mammoths Co-Existed In North America

An analysis of skeletal remains has provided new evidence that humans made it to the Western Hemisphere during the last ice age, where they lived alongside giant, now-extinct mammals, claims a new study published online Thursday in the Journal of Vertebrate Paleontology.

University of Florida researchers used rare earth element analysis in order to measure the concentration of naturally occurring metals absorbed during fossilization in human and mammal remains discovered in south Florida in the early 20th century.

The study, which was inspired by an ongoing debate amongst scientists regarding whether or not those fossils were from the same time period, discovered that modern man co-existed with mastodons, mammoths, and other massive mammals in North America about 13,000 years ago.

“The Vero site is still the only site where there was an abundance of actual human bones, not just artifacts, associated with the animals,” Barbara Purdy, anthropology professor emeritus at the university, archaeology curator emeritus at the Florida Museum of Natural History, and co-author of the study, said in a statement.

"Scientists who disputed the age of the human remains in the early 20th century just did not want to believe that people were in the Western Hemisphere that early. And 100 years later, every single book written about the prehistory of North America includes this site and the controversy that still exists," she added.

The fossils, which were found at Vero Beach between 1913 and 1916, led some leading experts to assert that the human skeleton remains were not as old as the mammal bones found at the site. No proof could be established either way at the time, because there were no dating methods in use at the time, the university said.

In this study, researchers analyzed samples taken from 24 human bones and 48 animal fossils housed at the Florida Museum. They were able to determine that all of the samples were from the late Pleistocene epoch, though the researchers confess that the method utilized in the study is not as precise as radiocarbon dating.

“The uptake of rare earth elements is time-dependent, so an old fossil is going to have very different concentrations of rare earth elements than bones from a more recent human burial,” lead author and Florida Museum vertebrate paleontology curator Bruce MacFadden said. “We found the human remains have statistically the same concentrations of rare earth elements as the fossils.”

“It is important to note that they [the authors] did not provide an absolute or chronometric date, rather the geochemistry shows that the trace elemental geochemistry is the same, thus the bones must be of the same age,” added Kenneth Tankersley, an assistant professor in the University of Cincinnati anthropology and geology departments.


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