Major and trace elements in the 100 m drilling core samples from Lake Baikal have been determined by ICP-AES (inductively coupled plasma atomic emission spectrometry), ICP-MS (inductively coupled plasma mass spectrometry) and INAA (instrumental neutron activation analysis). In this paper, vertical distribution profiles of the determined elements are presented. Raw analytical values will be presented elsewhere.
Vertical distribution patterns for Ti, Al, Fe, Mn, Ca and Pare shown in Fig.1. In the bottom surface sample (=the uppermost part of the core), the concentration of Al, Ti, Fe and Ca are relatively low and that of P is relatively high. It may indicate that relative large volume of biogenic organic substances are included in the bottom surface sample. In addition, it seems that the Mn contents are relatively low and its deviation is rather small between 60 m and 90 m from the bottom.
In order to get a complete geochemical signature, 14 P-rich concretions, chosen among the different cores, were acid digested (Table 3a and Table 3b). In a clean laboratory, 1.7 to 36 mg of concretions were digested overnight in a concentrated mixture of Suprapur acid (3 ml HCl/2 ml HNO3/1 ml HF) at 90 °C in sealed Teflon beakers. After evaporation to dryness, the residue was dissolved in 2.5 ml of 2% HNO3 Suprapur and diluted to 12 ml with Milli-Q water. During the same procedure, we have also dissolved and analysed, for comparison, a pure vivianite from Anlua, Cameroon (tubular crystals, MRAC collection).