Core samples taken in the African Rift Valley could help to clarify how past climate change is connected to human history and evolution.
An international collaboration of researchers led by several UA scientists are taking lake deposit samples from Kenya and Ethiopia to examine the relationship between the fossil record and past ecological conditions.
The Hominin Sites and Paleolakes Drilling Project started by taking core samples from dry lake beds in Kenya last summer and will continue in Ethiopia next summer and then return to Kenya the following summer.
“The only way to get in the time machine is to look at core samples,” said Andrew Cohen, principle investigator on the Hominin Sites and Paleolakes Drilling Project and a UA professor of geosciences.
The researchers are asking questions about how the ecosystem varied from year to year near archeological sites important to paleontological records and ancient hominids.
When core samples are taken, it provides a template of information that can help answer questions.
“We want to know what went extinct and why did certain organisms diffuse into other species,” said Cohen. There are many factors that contribute to the evolution of species, one of which could be climate change, according to Cohen.
In order to interpret data, researchers will develop system models from the data gathered from core samples to into scientific context.
“We (modelers) set the stage,” said Joellen Russell, principle investigator of modeling on the Hominin Sites and Paleolakes Drilling Project and UA associate professor of biochemical dynamics. “We have to get the global context down.”
Work on the samples taken this summer has not started yet, however research into the changes in temperature current and rainfall off of Africa is underway.
One set of fossils that will be researched are pollen fossils. Owen Davis, UA professor of palynology, will be heading this part of the project at the UA.
Looking at pollen fossils will help to give some indicator of what plants were living during that period of time which, in turn, may give clues into the ecological conditions surrounding the vegetation.
“Pollen analysis will tell us what plants grew where the extinct people lived,” Davis said.
Humans have historically settled near places of water. In order for a fossil to form, there needs to be sediment build up without disturbing the area, meaning moving bodies of water won’t allow for fossil accumulation, Cohen said.
The samples for this project produce records that can be picked apart from year to year. This will help researchers look at climate conditions on a yearly or seasonal basis.
“The lake sediment used in this study is millions of years old, so the relationship between our earliest ancestors and vegetation can be studied,” Davis said. “These lakes are nearer to key human-fossil localities than any studied before.”
