Micro-analytical study of the distribution of iron phases in ferromanganese nodules

The differentiation of Fe and Mn within the nodules its relation to fabric is a well-known phenomenon. However, relationship this mineralogy was not studied yet. This study aimed fill gap through micro-mineralogical geochemical investigation from soils with different hydromorphic conditions by electron probe microanalysis micro-X-Ray diffractometry. Different hydromorphism resulted in same nodule types their similar vertical distribution soils. In shallow groundwater table, exhibited more developed fabric, crystalline hydrous oxides (goethite) prevailed them. Contrarily, showed smaller size, lower enrichment, higher frequency non-crystalline regular flooding stagnant surface water. difference could be related intensity water oscillation shorter redox periods latter formation nodules’ may have been followed slow crystallization Fe-oxyhydroxides when favorable occur allowing subsequent recrystallization. association clay minerals also affected process nodules. Although observation assumed failed nodules, characterized Fe-oxyhydroxide mineralogy, at least progression process.