Radiochemical data for layers inside manganese crusts retrieved during the ROMANCHA campaign of the R/V Jean Charcot on the Romanche trench area (Atlantic ocean)

Radiochemical analyses have been performed on micro-samples extracted from various surface and inside layers of manganese crusts covering basalt or volcanic breccia rocks (see, Table Annex7-B). Non manganese oxide parts consisting essentially of the surrounding carbonate sediment inlays have been separated using hydrofluoric acid. After processing the samples have been dissecated at 110 Celsius and prepared as an aliquot from which a part is used for radiometric measurements using Alpha spectrometry and the other part is used for uranium-238 and thorium-232 using co-solvant precipitation.