Rare Earth Elements in the manganese deposit of Úrkút (Bakony Mountains, Hungary)

Abstract

First results are presented about the abundance and distribution of rare earth elements (REE) in the Úrkút manganese ore deposit. Geochemical analyses of samples of the manganese carbonate sequence reveal that the average REE content decreases from the base to the top. A positive Ce anomaly and the enrichment of REE in clay-rich units indicate that, in addition to adsorption of REE from sea water, a terrigenous REE source also displaying a positive Ce anomaly is involved. A Ce La ratio of 2.5 to 3.2 also indicates a terrigenous source for much of the REE in the samples studied. In the primary enrichment of REE, the clayey fractions played an important role. Oxidative processes have led to further enrichment of REE where primary carbonate ores have been altered to oxides. The clays in the ore deposit have no economic importance because their Mn content is very low. However, their distribution and enrichment in REE provides information about the conditions of formation of the deposit. Among the mining fields Csárdahegy differs in geochemical character from that of the field Shaft III and Kislöd.