Geothermometrie

Geothermometry is a technique used in geology and geophysics to determine the temperature of rocks and minerals at the time of their formation or at a later stage of their thermal history. It relies on the principle that the chemical composition and physical properties of certain minerals and mineral assemblages change predictably with temperature. By analyzing these changes in samples, scientists can infer the temperatures they experienced.

Several methods are employed in geothermometry. One common approach involves the study of phase equilibria in minerals. Minerals that form at specific temperatures will have distinct compositions. For example, the ratio of certain elements within a mineral, like the iron-magnesium exchange between olivine and pyroxene, is a well-established geothermometer. Another method uses the distribution of elements between coexisting minerals. If two minerals share a common element, its partitioning between them is temperature-dependent.

Geothermometry is crucial for understanding various geological processes. It provides insights into the conditions under which igneous and metamorphic rocks form, the thermal evolution of the Earth's crust and mantle, and the history of hydrothermal systems. Applications extend to resource exploration, such as identifying areas with high geothermal potential for energy extraction, and to understanding plate tectonics and mantle dynamics by reconstructing temperatures deep within the Earth. The accuracy of geothermometric estimates depends on the careful selection of appropriate mineral pairs or single minerals and the application of calibrated thermometers based on experimental data or thermodynamic models.