U th dating on calcite
Uranium-thorium dating, also called thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique commonly used to determine the age of calcium carbonate materials such as speleothem or coral.
As time passes after the formation of such a material, uranium-234 in the sample, with a half-life of 245,000 years, decays to thorium-230.Additionally, as yet there does not exist a calcite standard reference material for inter-laboratory accuracy and precision comparison, with most laboratories using their own in-house standard material and focussing largely on application to paleoclimate studies (e.g. In actively deforming regions, high-pressure hydrothermal fluids play an important role in faulting and vein formation, and commonly fault rupture is followed by rapid sealing through mineral precipitation.Therefore, precise dating of vein growth is of special importance to our understanding of the complex interplay between seismic events and fluid flow in the upper crust, and opens up a new field of study using U-Th techniques.This calls for wetter (than present) conditions during the last interglacial in the currently hyperarid northern Red Sea.The measurement of U-series isotopes in precipitated minerals such as calcite holds various challenges, including low U and Th concentrations (in the ppb-ppt range), and the presence of detrital 232Th which can lead to age overestimations.
Pristine aragonite skeletons of reef building corals can be rapidly recrystallized to calcite by the interaction of the corals with freshwater in coastal aquifers.