Faculty, researchers and students from USF and archaeologists from Ohio State University have collaborated to research a climate change that occurred nearly 5,000 years ago.

The group from USF made the trek to Yemen and spent a month looking into the possibilities of how the climate change altered the culture and way of life in the southern Arabian Peninsula.

“What we think we have evidence for is that between about 10 and 5,000 years ago, the Indian Ocean monsoon system brought a great deal more precipitation up across the Arabian Peninsula,” said researcher Rick Oches, the chair of USF’s Department of Environmental Sciences and Policy. “It allowed people to live more sustainably on the landscape than they’re able to now.

“About 5,000 years ago, the monsoon system shifted to the south, which resulted in the southern Arabian Peninsula becoming the extremely arid environment it is today,” Oches said.

The group of researchers applied a multi-disciplinary approach to their work. Oches terms this “geoarchaeology” and explained it as, “the application of geologic techniques to understand the environments and processes that preserve the archeologic record.”

The lives of people living in the Arabian Peninsula were much different 5,000 years ago, said Oches. “We think we have indications that people were just starting to learn the domestication of crops, which would require them to learn how to manage water. We have indications of things like check dams and irrigation canals that divert water from the slopes down onto the flatlands and valley floors.”

The transformation into an arid environment led to a reversion of the lifestyle of the people in the Arabian Peninsula. “With the climate change, they reverted back to the herding type of behavior since they were no longer able to sustain agriculture,” Oches said.

Despite the shift back to a nomadic lifestyle, there is evidence that the culture prior to the climate change used animals as well. “The main evidence we have for the use of animals is, this year, the archaeologists on the team discovered this spectacular ring of cattle skulls — probably a ritual ring of around 43 skulls — organized in a specific fashion that indicates some kind of ritual use of this creature,” Oches said.

Concerning the ring of cattle skulls, Oches also said that, “the primary thing of interest there is that the climate today can not support cattle; there is no cattle grazing going on in the region — it is just way too dry.”

Many cutting-edge technologies went into the research, Oches said.

“The main kinds of things we were using as geologists in the field were global positioning system (GPS) technology to do precision mapping of the geologic sediments that we were interested in understanding the origin and distribution of.

“The other technology we used was radio-carbon dating to understand the ages of the sediments, fossil plant remains and fossil animal remains that we find buried in the sedimentary record,” Oches said.

Scott Anderson, a senior in geology who accompanied the team to Yemen, mentioned one amazing instance where the mapping technology proved its accuracy.

“In one particular case, one of the archaeologists was able to look at this map and he saw something that caught his eye that appeared kind of like a white dot on the satellite image. When he went in person and investigated, it turned out to be a painted rock of maybe less than a meter in diameter. It didn’t really turn out to be anything significant archeology-wise, but the ability to see that from a computer and then go look and see what it is is significant.”

Oches called the ring of cattle skulls one of the greatest archeological finds of the trip.

“We have a site that we excavated that has one of the most impressive stone tool assemblages from the southern Arabian region ever discovered,” Oches said. “It’s a site that archaeologists will probably continue exploring for many years to come.

“The final conclusions have yet to be determined. What’s clear from the research is that the climate change that affected the region five thousand years ago was a very dramatic one that forced significant changes in behavior of people at the time. People are continuing to adapt to the extremely arid climate that, for the last several thousand years, has persisted in the region.”