Ancient Ocean History Preserved in Salted Secrets

Scientists have analyzed the chemistry of microscopic pockets of water trapped in crystals of sea salt to reconstruct the history of tectonic movement on the seafloor and gain insights into atmospheric conditions over the past 150 million years. By tracking the lithium content in marine halite, researchers were able to determine the decrease in tectonic plate activity and hydrothermal activity, which resulted in a drop in lithium concentration and a rise in magnesium to calcium ratios. This decrease in geological activity may have contributed to the cooling that produced the last ice age. The study highlights the interconnectedness of Earth's systems and the role of plate tectonics in regulating the hydrosphere and atmosphere.