Origin of manganese in nannofossil calcite based on synchrotron nanoxrf and xanes

Calcareous nannofossils are micrometric calcite platelets secreted by the photosynthetic algae named coccolithophores and incertae sedis. nannoplankton inhabit photic zone from coast to open-ocean have left an abundant fossil record since Triassic. Therefore, they constitute interesting material for geochemical studies although been overlooked in comparison foraminifera. We analyzed manganese distribution valence six calcareous nannofossil species representing different ages (Recent Jurassic) geological settings (land sections deep ocean core-tops) with structures assess potential of Mn as a paleobiological or paleoenvironmental proxy. Nano x-Ray Fluorescence (xrf) maps were established at esrf id22ni id21 beamlines k-edge Absorption Near Edge Structure (xanes) id21. is more pre-Quaternary rock samples than core-top samples. In samples, nanoxrf show distributions correlated primary crystalline organization whereas either absent does not follow crystal organization. Xanes analyses that form MnCO3. All these observations argue incorporation within controlled diagenesis through overgrowth secondary (Ca, Mn)CO3. Crusts grew along original growth directions. The some highlights early input when detached platelet lies on seafloor still water column. should therefore be considered critical tool identify diagenetic rather environmental conditions.