Geochemistry of natural waters – The legacy of V.I. Vernadsky and his students

The geochemist, Vladimir Ivanovich Vernadsky has only recently become recognised internationally, despite being regarded as one of the greatest names in science of the 20th century in his homeland Russia. There are several reasons for his lack of renown in the west, but mainly because his most important work “The Biosphere” was only fully translated into English in 1997. This book and the ideas it contains are now becoming regarded as one of the pioneering works of the last century. It defines the biosphere as a unifying, holistic concept for the earth system at a time when reductionism was the driving motivation in scientific research. Above all, for earth scientists, Vernadsky regarded life as the driving geological force. However another, as yet unpublished work (in three volumes) entitled “The History of Natural Waters” also deserves similar attention. This book explores many concepts in hydrogeology, geochemistry, geofluid circulation and especially biology in which water is described as an integral part of the biosphere.     

Accumulation Dynamics of Polycyclic Aromatic Hydrocarbons in Lake Baikal Bottom Biocenoses Assessed from Biogeochemical Monitoring Data

The results of long-term biogeochemical monitoring of Lake Baikal are presented. The accumulation is studied of polycyclic aromatic hydrocarbons (PAHs) in bottom sediments and macrozoobenthos that were synchronously sampled at the same stations. The stations are located in the areas where anthropogenic impact on the lake is high: in the area of the former Baikal Pulp and Paper Mill (BPPM), in the footprint of the BAM railway in the north of the lake and in the Selenga River delta front as well as in the zones of coastal fouling in the area of BPPM. It is found that variations in the concentration of PAHs in macrozoobenthos do not directly depend on those in the sediments. It is revealed that the maximum concentration of benzo[a]pyrene in the area of the former BPPM is almost by eight times higher than in the other areas of the lake; shallow-water macrophytes accumulate more polyarenes than deep-water macrozoobenthos.     

Distribution of structural impurities and fluid microinclusions in cubic and coated diamond crystals from the Udachnaya pipe,Yakutia, Russia

FTIR microspectroscopic data were used to construct two-dimension maps showing the distribution of structural impurities and mineral microinclusions in cubic and coated octahedral diamond crystals from the Udachnaya kimberlite pipe in Yakutia. Elevated concentrations of hydrogen and total nitrogen are detected in parts corresponding to the early growth of single-episode growth regions of diamond crystals. These concentrations decrease toward the peripheral portions of these regions. The microinclusions contain water and polyphase mineral associations that preserve a high residual pressure. Microinclusions in the coats of octahedral diamond crystals are dominated by silicates, in which the intensity of IR spectral bands increases toward the peripheries, whereas the cubes posses irregularly distributed domains rich in these phases. The carbonate phases of the microinclusions are distributed according to growth zones of the crystals, and their distribution is often not correlated with the concentrations of structural impurities. The facts that microinclusions in the diamond cuboids are dominated by carbonates and that the rims of the octahedra are dominated by silicates suggest that the diamonds crystallized from dominantly carbonate and silicate fluids/ melts, respectively. The chemical composition of the microinclusions point to an eclogitic paragenesis of the crystals. Facts are obtained that provide support for the earlier hypothesis that cubic diamond crystals and coated octahedral crystals grow at metasomatic interaction between deep fluids and eclogitic rocks in the lithospheric mantle.