MINERALOGICAL AND GEOCHEMICAL CHARACTERIZATION OF TERRESTRIAL-HYDROGENETIC FE-MN-NODULES OF THE TRABZON AREA, NE TURKEY

Mineralogical and geochemical characteristics of Fe-Mn-enrichments in reddish and brownish recent soils in the eastern part of the Black Sea region of Turkey were investigated. The enrichments occur as nodules and layers. The nodules can be subdivided into mono- and polynodules. Mn contents of the polynodules vary from 4.6 to 10.2 wt.% and Fe-conte nts from 6.4 to 11.7 wt.%, whereas the mononodules show Mn contents fr om 14.1 to 16.4 wt.% and Fe contents varies from 33.0 to 35.6 wt.%. Mo st of the Mn is in amorphous compounds. Mn-minerals identified by X-ra y diffractometrical methods are nsutite, hollandite, jacobsite, mangan ite, pyrolusite etc., in addition to some Fe-oxyhydrates. The chemical analyses also indicate the presence of several trace element such as Co, Ni, Cu and relatively high Ti- and Al-contents. According to the p resent field investigations and chemical analyses it is assumed that t he element concentrations of these Fe-Mn-nodules and layers resulted f rom intensive weathering of the basaltic, andesitic and partly dacitic lavas and pyroclastics.