Manganese in alcaline rocks

The estimation of the average World contents of manganese (Clarke values) in alcaline igneous rocks, as well as of Mnmodule (MM = Mn/Fe) is given for the first time. The estimation is performed for 4 types of alkaline rocks: ultrabasic, basic, medium and acid ones. In the first two rocks, manganese Clarkes are close to such in normal (not alkaline) analogues, but Mn Clarkes and average MM values in medium and acid alcaline rocks are noticeably higher vs. normal analogues. The correlation Mn-K is found in ultrabasic rocks only, whereas Mn-Na correlation is characteristic for all the rest alkaline rocks.