Aspects of the Biogeochemistry of Magnesium 1. Calcareous Marine Organisms

A study was made of the factors controlling the distribution of magnesium in the calcareous skeletons of marine organisms. The mineralogy of the carbonate appears to be the most important influence, with large amounts of magnesium occurring in solid solution in the calcitic forms and generally lesser amounts in the aragonitic forms. The complexity of the organisms and the temperature of the water in which they lived are also controlling factors in the amount of magnesium present. A large part of the study, both mineralogical and chemical, was made with X-ray diffraction techniques.