• In this work the geochemistry of REE-rich karst bauxite ore from several deposits of the Sierra de Bahoruco (Dominican Republic) has been investigated. The bauxite ores are geochemically heterogenous and show differences with respect to major, minor and trace elements. According to their major element geochemistry, the studied ores classify mostly as Fe-rich bauxites. The minor elements Cr and Ni are in general relatively high (up to 1250 and 2370 ppm, respectively), hence pointing towards a (ultra-)mafic source for the bauxite formation. The sum of REE contents range from similar to 400 to similar to 5400 ppm (average similar to 1200 ppm) at varying LREE/HREE between similar to 1 and similar to 25 (average similar to 8). In general, REE chondrite-normalized patterns for studied bauxites show negative Ce and Eu anomalies with rather flat segments for HREE. However, three samples from different bauxite ore deposits with the highest REE contents show significant enrichment trends for heavier REE, particularly for Pr, Nd, Sm, Gd as well as for Tb and Dy (one sample). Mineralogical studies reveal that formation of secondary REE-bearing minerals (i.e. phosphates, carbonates and oxides) occurred. Karst bauxite ores hosted in the Sierra de Bahoruco represent an excellent natural laboratory to study the geochemical behaviour of REE in weathering systems.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)

Nyckelord

Applied Geochemistry

Tillämpad geokemi

Publikations- och innehållstyp

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