(Fig 2, page 399), Distribution of Fe and Mn in ferromanganese nodules of the Eningi-Lampi Lake, Russia

The distribution of Mn and Fe in water, sediments, hydroxide nodules and crusts of Eningi-Lampi ore-bearing lake is regular, and concordant from the source to the areas of accumulation of these components. Mn-Fe hydroxide nodules and crusts occur at the water-sediment interface, and more rarely in the upper (0-5 cm) film of brown watery mud. The leading role in the formation of Mn-Fe nodules and crusts is played by the chemosorption and auto-catalytic oxidation in the course of interaction of component-bearing solutions with active surfaces. This is considered to be the basic process for the model of ferromanganese ore formation in recent basins. Despite the differences in the physico-geographical and geochemical characteristics of lakes, mediterranean seas and oceans, the formation of ferromanganese hydroxide nodules and crusts in these basins may be explained by this model.

Age determination of sediment core HZM, lake Holzmar (Tables 1, 2)

AMS radiocarbon ages have been determined on terrestrial macrofossils selected from the annually laminated sediments of lake Holzmaar (Germany). The radiocarbon chronology of this lake covers the last 12.6 ka. Comparison of the radiocarbon dated varve chronology with tree ring data shows that an additional 878 years have to be added to the varve chronology. The corrected 14C varve chronology of Holzmaar reaches back to ca. 13.8 ka cal. BP and compares favourably with the results from Soppensee (Switzerland) (Hajdas et al., 1993, doi:10.1007/BF00209748). The corrected ages for the onset and the end of the Younger Dryas biozone are 11,940 cal. BP and 11,490 cal. BP, respectively. The ash layer of the Laacher See volcanic eruption is dated at 12,201 ± 224 cal. BP and the Ulmener Tephra layer is dated at 10,904 cal. BP.