TY - JOUR A1 - Cabral, A.R. A1 - Radtke, Martin A1 - Munnik, F. A1 - Lehmann, B. A1 - Reinholz, Uwe A1 - Riesemeier, Heinrich A1 - Tupinambá, M. A1 - Kwitko-Ribeiro, R. T1 - Iodine in alluvial platinum-palladium nuggets: evidence for biogenic precious-metal fixation JF - Chemical geology N2 - Synchrotron radiation-induced X-ray fluorescence (SR-XRF) spectrometry was applied to determine iodine concentrations in alluvial Pt–Pd aggregates with delicate morphological features from Córrego Bom Sucesso, Minas Gerais, Brazil. The millimetre-sized botryoidal and rod-shaped grains of alluvial Pt–Pd–Hg intermetallic compounds have surprisingly high concentrations of iodine, in the range from 10 to ~ 120 μg/g. Because iodine is a strongly biophile element, known to be enriched in peatlands and plant remains in soils by microbial activity, its concentration in the Pt–Pd nuggets suggests biogenic precious-metal fixation in the aqueous alluvial milieu. Biogenic and inorganic processes, such as bioreduction and electrochemical metal accretion, could mutually have contributed to the growth of nanoparticles, formed on organic templates, to millimetric Pt–Pd nuggets. KW - Lodine KW - Pt-Pd nuggets KW - Córrego Bom Sucesso KW - Minas Gerais KW - Brazil PY - 2011 DO - https://doi.org/10.1016/j.chemgeo.2010.12.003 SN - 0009-2541 SN - 1872-6836 VL - 281 IS - 1-2 SP - 125 EP - 132 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-23174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -