oxygen isotope geothermometer

The oxygen isotope geothermometer is a method used in geology to determine past temperatures. It relies on the principle of isotopic fractionation, where different isotopes of an element behave slightly differently in chemical or physical processes. Specifically, the ratio of oxygen-16 to oxygen-18 in materials like calcium carbonate, secreted by marine organisms, is influenced by the water temperature. By measuring these ratios in fossils, scientists can estimate ancient ocean temperatures, aiding in the study of climate change and ice ages. This technique is a form of geologic thermometer, which is any mineral or mineral aggregate that provides information about the temperature conditions under which it formed.123