A geochemical isotope model of the nitrogen cycle

Using the compartment theory and appropriate computer codes, a new model of the nitrogen cycle for the earth crust and atmosphere has been subjected to a mathematical approach. Proceeding from the mathematical modelling of the time-dependent nitrogen distribution, modelling of the 15N distribution has been carried out, considering isotopic effects in the geosphere. Based on the chosen model quantitative data are given of the isotopic exchange with the upper mantle, of isotope effects of nitrogen chemically fixed in sediments and in metamorphism, and of the delta 15N values of magmatic and atmospheric nitrogen in the initial stage of crust development