Scientists from the Pacific Northwest National Laboratory (PNNL) discovered a rock containing water from an inland sea 390 million years ago, which was located in upstate New York, in the United States.
The discovery of this microscopic ‘pocket of seawater’ opens the way to understanding how Earth’s oceans They change and adapt to climate change over thousands of years.
During the Middle Devonian period, this inland sea extended from present-day Michigan to Ontario, Canada. It was home to coral reefs that rivaled Australia’s Great Barrier Reef. Truck-sized sea scorpions roamed the waters that were home to now-extinct creatures like trilobites and the earliest examples of horseshoe crabs.
But eventually the climate changed, and with that change, most of the creatures and the sea itself disappeared, leaving only fossil remains embedded in the sediment that eventually became the pyrite rock sample used in the present experiment.
V said a permit Sandra Taylor, first study author and scientist at PNNL.
Taylor led the analyzes in collaboration with geochemists Daniel Gregory of the University of Toronto and Timothy Lyons of the University of California, Riverside. The research team reported their discovery in the December 2022 issue of Earth sciences and planetary messages.
Discover the smallest pockets of sea water
Many minerals and gemstones contain small pockets of fluid. In fact, some gemstones are prized for their liquid bubbles that trap light inside. What’s different about this study is that the scientists were able to reveal what was inside the smallest pockets of water using microscopy and advanced chemical analysis.
The researchers used the rock samples as evidence to reconstruct how the climate changed over a long period of geological time.
“We use mineral deposits to estimate the temperature of the ancient oceans,” said Gregory, a geologist at the University of Toronto and one of the study leaders. But there are relatively few useful examples in the geological record.
“Trapped Seawater Salt Deposits.” [halita] It is relatively rare in the rock record, so this data has been lost for millions of years and what we currently know is based on a few sites where halite has been found,” Gregory said.
By contrast, pyrite is found everywhere. “Sampling with this technique could unlock millions of years of geological record and lead to new understanding of climate change.”
“Little bubbles” inside the metal
The research team was trying to understand another environmental problem, the leakage of toxic arsenic from the rocks, when they noticed the small flaws. Scientists describe the appearance of these particular pyrite minerals as framboides, derived from the French word for berries, because they look like clusters of pieces of berries under a microscope.
“First, we looked at these samples through an electron microscope and saw these kinds of little bubbles or miniature features within the framework of the frame and wondered what they were,” Taylor said.
Using the delicate and sensitive detection techniques of atomic probe tomography and mass spectrometry, which can detect minute amounts of elements or impurities in minerals, the team discovered that the bubbles contained water and that their salt chemistry matched that of ancient seas.
These types of studies also have the potential to provide interesting information about how hydrogen or other gases can be stored safely underground.
Hydrogen is being explored as a low carbon fuel source for various energy applications. This requires the ability to recover large amounts of hydrogen and store it safely in underground geological reservoirs. Therefore, it is important to understand how hydrogen interacts with rocks.”
“Atomic probe tomography is one of the few techniques where you can not only measure hydrogen atoms, but also see where they go in a mineral. This study suggests that small defects in minerals can be potential traps for hydrogen. So with this technique, we can figure out what It occurs at the atomic level, which will then help evaluate and improve underground hydrogen storage strategies.”
Typical creator. Subtly charming web advocate. Infuriatingly humble beer aficionado.