Inside a grain of salt, you can find a tiny archive - a record of the waters in which that crystal precipitated out, drying under an ancient sun.
A visiting scholar from France, Emmanuel Guillerm hopes to crack open that ancient saline library for clues about a pivotal time for humanity: the advent of agriculture 12,000 years ago in the ancient Near East, the first glimmers of what we now know as civilization.
A native of Brittany, Guillerm came to the United States specifically to work with Distinguished Professor of Earth Sciences Tim Lowenstein by way of a Marie-Curie postdoctoral fellowship. Lowenstein is one of the world's foremost specialists in saline environments and has collected and analyzed salt samples from around the world during the course of his research.
During the third year of the fellowship, Guillerm will bring the knowledge he has acquired back to his host lab at the Helmholtz Centre Potsdam GFZ German Research Center for Geosciences.
"Dr. Guillerm is using new laboratory techniques, computer modeling and creative thinking to document the past climate of the Middle East," Lowenstein said. "He is part of the new generation of Earth scientists who are reconstructing ancient climates on Earth at a new level of detail."
Binghamton possesses the necessary equipment and expertise to drill into salt crystals with a laser and access the fluid trapped within, known as a "fluid inclusion", a tiny bit of the water in which the crystal formed.
"If you look, you can find the chemical composition of these fluid inclusions, and you can learn something about the composition of the lake or ocean where they formed," Guillerm explained.
During his doctoral research in France and post-doctoral research in Israel, Guillerm developed new and novel techniques for reconstructing past temperatures from the salt deposits in salt lakes, particularly the Dead Sea in the Middle East.
"It's the same mechanism as a mercury thermometer, in which the level of mercury changes as a function of the air temperature," he said. "Any material will expand with increased temperature. It's the same with saline water; it is less dense at higher temperatures."
The density of the water trapped within salt crystals remains consistent with the exact moment of the crystal's formation. In other words, it's like freezing a mercury thermometer in time.
The Dead Sea, located at the border between Israel, Jordan and the West Bank, is a particularly fascinating place. No other deep perennial saline lake is currently precipitating salt, although there are thick, old salt deposits in places such as Wyoming's Green River Basin and beneath the bottom of the Mediterranean Sea; the latter is believed to date back to lowered water levels in the Mediterranean between 5 and 6 million years ago, Guillerm said.
To form, salt lakes require a geographic depression with no outlet for water. The Dead Sea is actually the lowest place on earth, at 400 meters below sea level; water only leaves the basin through evaporation, leaving salt behind.
In 2011, researchers obtained 450 meters of sediment from the bottom of the Dead Sea, an archive of the past 200,000 years. Lowenstein and Guillerm are looking to reconstruct the climate during the last 12,000 years - a period after the end of the last Ice Age when agriculture began in the Jordan River valley before spreading throughout the Middle East, northern Africa and Europe.
How hot was it during that time? How much rainfall watered those early crops?
"We think that we may be able to gain new insights on the development of human civilizations," Guillerm said.
