Marine Isotope Stages

Marine Isotope Stages (MIS) are periods in Earth's history identified through the analysis of ocean sediment cores, which contain layers reflecting changes in climate. These stages track variations in Earth's climate, particularly glacial and interglacial periods, through isotopes of oxygen found in fossilized marine organisms. When global temperatures rise, lighter oxygen isotopes become more prevalent; when temperatures drop, heavier isotopes dominate. By comparing these isotope ratios, scientists can reconstruct a timeline of Earth’s climate changes over hundreds of thousands of years, providing insight into natural climate shifts and helping us understand current climate change.