Vol 72, No 6 (2017)

The complex tectonic structure of the Okhotsk Sea shelf and the high level of geodynamic activity necessitate the use of geodynamic simulations to forecast the secondary filtration-capacity properties of reservoirs. The 3D geomechanical models were built and the forecasting of the fractured porosity and permeability was conducted for the Kirinskaya, Ayashskaya, and East-Odoptinskaya license areas. The simulation revealed filtration channels, where both vertical and horizontal migration of hydrocarbons occur. It was found that the secondary permeability of the upper and the lower stratigraphic horizons of the studied area significantly differ. The Okobykai clayey member is the boundary surface and serves as the regional cap. All calculations were performed on the 3D-grid geological model, which allows us to use the data for hydrodynamic simulation.

A sequence of clays and clayey siltstones with olistostrome horizons and olistoplaques of the Upper Cretaceous rocks occur in the coastal section northwest of the mouth of the Agoi River. The rocks of this sequence are mostly gray sandy calcareous clays with rare interlayers of siltstones. The horizons and lenses of olistostromes contain small clasts, large blocks, and olistoplaques of rocks of various ages. The microfauna from matrix and clasts of olistostromes of different horizons of the sequence was sampled and identified. The large blocks and olistoplaques are tectonized with formation of slickensides and cracks, which do not travel beyond the country rocks. The thickness of the sequence is 280 m.

The chemical composition of interstitial waters from several inland seas and or water system (NPWS) exposed to anthropogenic pollution was studied. The patterns of the distribution of pollution in the Dnieper–Bug Estuary, Gelendzhik Bay of the Black Sea and in the Alexandria’s Eastern Harbor of the Mediterranean Sea were found. Most of the contamination occurs in the upper layers of bottom sediments and near mouth zones. A significant role is played by secondary contamination related to the dissolution and accumulation of metals and nutrients in the interstitial water and their migration to the water column. The estuary factor of anthropogenic pollution takes center stage according to a factor analysis for the combined impacts of potentially mobile forms of metals in the Dnieper–Bug Estuary. Studies of the Lake Pyasino pollution near Noril’sk were carried out.

This work presents the results of the first comprehensive study of PGE mineralization from massive chromitites of the Iov dunite body (Northern Urals). The chromitites are composed of chromespinelides with a higher content of Cr₂O₃ with respect to those from other zonal clinopyroxenite–dunite massifs of the Urals. However, the composition of chromespinelides fits the trend that is characteristic of the dunite–clinopyroxenite–gabbro formation. PGE minerals, in particular Pt–Fe solid solutions, were identified in chromitites and in chromespinelides in the form of crystals and aggregates of a complex non-crystallographic habit and less often of an idiomorphic cubic habit. In terms of stoichiometry, Pt–Fe minerals correspond to ferroplatinum (Pt₂Fe) and isoferroplatinum (Pt₃Fe). The minerals of the isomorphic tetraferroplatinum–tulameenite–nickelferroplatinum series are widely distributed. Thus, the PGE mineralization of the Iov dunite body has features that are characteristic of clinopyroxenite–dunite massifs of the Urals.