Chemical composition of manganese nodules from GH78-1 cruise

Fifty-seven samples of manganese nodules from the GH78-1 area were analysed in bulk rock for major and some minor metal elements to provide the data for the evaluation of the chemical features of the nodules. Air-dried sample of 0.1 g was decomposed with a mixture of 5 ml of hydrochloric acid and 5 ml of nitric acid in a covered 50 ml beaker on a boiling bath for about 30 minutes. After cooling, the solution was filtered into a 100 ml calibrated flask and diluted to the mark with water. The analyses for Mn, Fe, Co, Ni, Cu, Zn and Pb were done by atomic absorption spectrometry. The total water was analyzed gravimetrically.