The variations of hydrogen index pH in the bottom sediments of North-Eastern outskirts of the Black Sea in the region of the Gudauta uplift are studied. Here the potentially oil- and gas-bearing structures and carbonaceous reef-forming buildings are singled out by seismic data. The sampling of bottom sediments was carried out in the course of the maritime science-research expedition in the August of 2010. The sampling stations were placed at 7 profiles oriented perpendicular to the coast line, 1500 m further on. The profiles were placed at the distance 3000 m from each other. In all, 260 samples were picked out. The pH measurement was carried out by potentiometric method using the analyzer Expert-001, measuring electrode and chlorine-silver comparison electrode. The established pH values are in the interval of 7.68–9.3. The median value makes 8.16, modal – 8.1, mean arithmetical – 8.26, at inaccuracy of average estimation – 0.037. The planar interpolation of pH values of bottom sediments was carried out in the environment ArcGis 9.1 with use of function kriging. It was established that marine sediments in the limits of Gudauta uplift are characterized by increased values of pH (7.86–9.27), in comparison with sediments of other sections of continental outskirts of Black Sea (7.55 – 8.4 at the Crimean shelf, 7.14 – 8.7 at the South-Eastern continental slope), i.e. are more alkaline. For all that, anomalous values of pH do not depend on the composition of sediments and coincide with the shelf zone and leveled parts of continental slope. It is established that the anomalous pH values of bottom sediments, according to published data, can be tied with the flows of carbohydrate fluids, ascending from industrial deposits. These fluids are oxidized at the interaction with oxygen of the seawater bicarbonate and also with methane-oxidizing bacteria. Therefore, the established by us spatial coincidence of areas of anomalously increased pH indices of bottom sediments of Gudauta uplift with areas of development of potentially oil- and gas-bearing geological structures, revealed earlier by seismic data, is connected with possible existence of carbohydrate deposits in them.
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