Distribution of various components in a hydrogeneous ferromanganese noduleand an Afanasiy Nikitin Seamount crust from Indian Ocean - A geochemical study using micro-PIXE

The present study emphasizes the geochemical features pertaining to the dis tribution of the major and minor elements in a hydrogenous ferromanganese, nodule and a seamount crust originating from the Indian Ocean. The micro-PI XE elemental maps indicate the successive layer formation of Fe and Mn in t hese deposits. A Ni association with Mn has been further confirmed by obser ving a Ni-Mn spatial correlation together with their compositional correlat ion. In addition, the core or the nucleus of the ferromanganese nodule was found to be rich in Fe and not Mn, which strengthens the assumptions made e arlier that the nodule formation started with Fe deposition which catalysed the growth of a ferromanganese nodule or crust by successive deposition of Mn and Fe. Irregular patterns of Mn and Fe layers were observed and discus sed. Instead of the more often studied Co-Fe association in nodules and cru sts, the intra nodule microanalysis revealed a Co-Mn correlation that will be discussed in this paper. (C) 2001 Elsevier Science B.V. All rights reser ved.