This seawater is 20,000 years old and has remained intact since the last ice age

Twenty thousand years ago, life on Earth was much colder. It was the end of a 100,000-year-old ice age – also called the last glacial maximum – and huge layers of ice covered much of North America, from Northern Europe and Asia. (If they had existed at the time, New York, Berlin and Beijing would have all been buried in the ice.)

Scientists are accustomed to studying this thrill in Earth's history by examining coral fossils and seabed sediments, but a team of Pacific Island researchers may have found a piece of the past that drives out all the others: a real sample of 20,000 years old seawater extracted from an ancient rock formation in the Indian Ocean.

According to the researchers, who described the discovery in a study to be published in the July 2019 issue of the journal Geochimica and Cosmochimica Acta, this discovery represents the first remnant of the ocean as it appeared during the the last ice age of the Earth.

The researchers found their aquatic advantage by taking samples of sediment cores from the underwater limestone deposits that make up the Maldives archipelago in South Asia. After transporting each core on their research vessel, the team cut the rock like a cookie dough tube and placed the pieces in a hydraulic press that extracted the remaining moisture from the pores. [Photos: Traces of an Ancient Ice Stream]

When the researchers tested the composition of these samples of freshly squeezed water aboard their ship, they were surprised to find that the water was extremely salty – much saltier than the Indian Ocean today. They did more tests on Earth to look at the specific elements and isotopes (versions of the elements) that made up the water, and all the results seemed to be out of place in the modern ocean.

In fact, everything in these water samples indicated that they came from a time when the ocean was significantly saltier, colder and more chlorinated – exactly as one would have thought during the last ice maximum, when the ice caps glaciers sucked in the seawater and let it fall. sea ​​levels hundreds of feet below current levels.

"Everything seems to indicate that we now have a piece of this 20,000-year-old ocean," said Clara Blättler, lead author of the study, assistant professor of geophysical science at the University of Chicago, in a communicated.

If these results actually hold water, the new samples provide a first direct look at the ocean's reaction to the geophysical fluctuations of the last ice age. This understanding could lead to better climate models to help understand our own changing world, said Blättler, since "any model you build on the climate must be able to accurately predict the past".

Note: At the time of publication of this article, no one had yet asked to drink the old juice from the ocean.

Originally published on Science live.