A brief analysis of the significant geological results of the last period obtained at the Institute of Nature Management of the National Academy of Sciences of Belarus, presented in the form of two blocks, including projects of fundamental and applied importance, is given. The fundamental developments of this period include studies on the fault tectonics of Belarus, synrift geodynamics of the Pripyat trough, the ecological and tectonophysical environment of Belarus, suture zones on the territory of Belarus, a geological and geophysical model of the deep structure of the Earth's crust according to the Georift-2013 profile, unconventional sources of hydrocarbon raw materials of Belarus. Among the developments of an applied nature are the creation of a model of the oil and geological zoning of the Pripyat trough, the justification of studies on the geological and geophysical profile "Vostochny", the features of the manifestation of natural mercury in the geological environment, the justification of oil work on Poznyakevichskaya Square and systematic studies of priority areas of the Pripyat trough, geological and geophysical studies on the Vechernegorskaya area of Antarctica.

Samples of coal and peat of different ages from the deposits of Belarus were first studied for the content of plant steroid hormones (brassinosteroids) using independent methods of enzyme immunoassay and HPLC-MS/MS. The quantitative determination of brassinosteroids showed that all the studied samples contained phytohormones of the main natural groups (brassinolide, 24-epibrassinolide, and 28-homobrassinolide), except for brassinolide in the oldest sample. The measured content of brassinosteroids corresponded to that characteristic of modern plant objects, and the composition of brassinosteroids varied depending on the depth of occurrence and other factors. The data obtained may indicate a high stability of plant steroid hormones and their supposed role as bioregulators over a long period of plant evolution.

The content of plant hormones (brassinosteroids) in oil samples from a number of oilfields in Belarus is determined using an enzyme immunoassay method. Brassinosteroids of the brassinolide, 24-epibrassinolide, and 28-homobrassinolide types have been found in fossil material for the first time. The brassinosteroid content of oil varies from 0.87 to 8.82 ng/g, which is comparable to their content in plant objects.

The Palaeoproterozoic crust and upper mantle in the region between the Ukrainian and Baltic shields of the East European Craton were built up finally during collision of the previously independent Fennoscandian and Sarmatian crustal segments at c. 1.8-1.7 Ga. EUROBRIDGE seismic profiling and geophysical modelling across the southwestern part of the Craton suggest that the Central Belarus Suture Zone is the junction between the two colliding segments. This junction is marked by strong deformation of the crust and the presence of a metamorphic core complex. At 1.80-1.74 Ga, major late to post-collisional extension and magmatism affected the part of Sarmatia adjoining the Central Belarus Zone and generated a high-velocity layer at the base of the crust. Other sutures separating terranes of different ages are found within Sarmatia and in the Polish-Lithuanian part of Fennoscandia. While Fennoscandia and Sarmatia were still a long distance apart, orogeny was dominantly accretionary. The accreted Palaeoproterozoic terranes in the Baltic-Belarus region of Fennoscandia are all younger than 2.0 Ga (2.0-1.9, 1.90-1.85 and 1.84-1.82 Ga), whereas those in Sarmatia have ages of c. 2.2-2.1 and 2.0-1.95 Ga. Lithospheric deformation and magmatism at c. 1.50-1.45 Ga, and Devonian rifting, are also defined by the EUROBRIDGE seismic and gravity models.

The solution of the several problems of neogeodynamics phenomena investigation and mapping was one of the main tasks of the IGCP project No 346 " Neogeodynamics of Baltic Sea Depression and adjacent areas ". Investigations performed for the project resulted in a series of international geodynamic maps showing vertical movements at the neotectonic stage, bottom part of Quaternary deposits, recent vertical movements, tectonic stress, epicenters of earthquakes, Moho discontinuity, neotectonic zoning and so on (Aizberg et.al., 2001; Garetsky et. al., 2003). Hence, the water surfaces of the Baltic Sea and the cast part of the North Sea, the southern part of Scandinavia, the German-Polish Depression, the Central European block mountains and depressions, western part of the Russian Plain and, partly the Carpathians, were mapped. Despite of, that was done in traditional manner without any digitization, the set of maps showing structure and its dynamics from the Quaternary capping down to the Moho surface fulfils requirements of the modem Information Technology, thus it may and can be computerized in follows of the GIS rules. That will enable authors to supplement project with the newest data, and restructure its visual appearance, in the attached presentation, authors review some problems of geodynamic researches in Belarus.

All faults in the territory of Belarus can be separated into two main types: pre-platform and platform faults. Geophysical (seismic sounding, gravity and magnetic surveys, borehole logs, etc.) and geological (structural, stratigraphic, etc.) data have been collected for all of these faults. Platform faults are the main object of the investigation because numerous mineral resources are connected with these faults, for example oil, gas, fluids, gypsum and potassium salt. Platform faults appear in the sedimentary paleo-basins formed in the Pripyat Trough, Orsha and Podlyasje-Brest Depressions, and in some smaller synformal structures of Belarus (Figure 1).

We present new results on the structure resulting from Palaeoproterozoic terrane accretion and later formation of one of the aulacogens in the East European Platform. Seismic data has been acquired along the 530-km-long, N–S-striking EUROBRIDGE'97 traverse across Sarmatia, a major crustal segment of the East European Craton. The profile extends across the Ukrainian Shield from the Devonian Pripyat Trough, across the Palaeoproterozoic Volyn Block and the Korosten Pluton, into the Archaean Podolian Block. Seismic waves from chemical explosions at 18 shot points at approximately 30-km intervals were recorded in two deployments by 120 mobile three-component seismographs at 3–4 km nominal station spacing. The data has been interpreted by use of two-dimensional tomographic travel time inversion and ray trace modelling. The high data quality allows modelling of the P- and S-wave velocity structure along the profile. There are pronounced differences in seismic velocity structure of the crust and uppermost mantle between the three main tectonic provinces traversed by the profile: (i) the Pripyat Trough is a ca. 4-km-deep sedimentary basin, fully located in the Osnitsk–Mikashevichi Igneous Belt in the northern part of the profile. The velocity structure is typical for a Precambrian craton, but is underlain by a ca. 5-km-thick lowest crustal layer of high velocity. The development of the Pripyat Trough appears to have only affected the upper crust without noticeable thinning of the whole crust; this may be explained by a rheologically strong lithosphere at the time of formation of the trough. (ii) Very high seismic velocity and Vp/Vs ratio characterise the Volyn Block and Korosten Pluton to a depth of 15 km and probably also the lowest crust. The values are consistent with an intrusive body of mafic composition in the upper crust that formed from bimodal melts derived from the mantle and the lower crust. (iii) The Podolian Block is close to a typical cratonic velocity structure, although it is characterised by relatively low seismic velocity and Vp/Vs ratio. A pronounced SW-dipping mantle reflector from Moho to at least 70 km depth may represent the Proterozoic suture between Sarmatia and Volgo–Uralia, the structure from terrane accretion, or a later shear zone in the upper mantle. The sub-Moho P-wave seismic velocity is high everywhere along the profile, with the exception of the area above the dipping reflector. This velocity change further supports a plate tectonic origin of the dipping mantle reflector. The profile demonstrates that structure from Palaeoproterozoic plate tectonic processes are still identifiable in the lithosphere, even where younger metamorphic equilibration of the crust has taken place.

The map characterizing density of Earth crust matter in whole Belarus region was originally charted using geophysical data bank. Main density heterogeneities were found to be concentrated in upper and lower crust while the middle part is relatively homogeneous. Fennoscandia and Sarmatia segments having minor density differentiation are characterized by compressed crust. The junction area - Central Belarus zone is distinguished by heterogeneous density.It was concluded that crust density may serve an indicator of processes responsible for tectonic architecture of the region.

Geodynamic characteristics of the paleorift structures of various age found in the territory of Belarus were described and compared. It was demonstrated that different kinds of deep rifting mechanism were responsible for geodynamic peculiarities of paleorifts formation and mineragenesis.

During EUROBRIDGE'96 seismic data were acquired along a 544-km NW-SE profile, from the East Lithuanian Belt (EL) to the Ukrainian Shield. Explosive sources from 16 shotpoints at 30-km intervals were recorded by 114 three-component seismographs deployed at 3-4-km intervals along the profile. Tomographic inversion and raytrace modelling, integrated with results from the EUROBRIDGE'95 experiment, established a two-dimensional P-wave velocity lithospheric model and the spatial variation of V-p/V-s. Sedimentary cover in Belarus consists of two principal layers with P-wave velocities of about 2.3 and 4.0 km/s. Upper, middle and lower crystalline crust exhibit velocities of 6.1-6.3, 6.4-6.8 and 6.9-7.2 km/s, and are characterised by low velocity gradients and small contrasts at boundaries. The crust below Belarus is about 50 km thick with Moho elevations of a few kilometres. Mantle P-wave velocities immediately beneath the Moho are generally 8.2-8.4 km/s. A lower lithosphere reflector occurs at 65-70 km di:pth. S-wave velocities are high in the upper crust and low in the lower crust. Our crustal model shows similarities to results from Scandinavia. High lower-crustal velocities and a crustal thickness of about 50 km (common features of Proterozoic crust) are observed throughout the EUROBRIDGE'96 profile. The boundary between the EL and West Lithuanian Granulite Domain (WLG) is associated with pronounced crustal velocity changes, and a thinning of crust towards the northwest. The WLG may be part of a larger southern Baltic Sea tectonic unit. Correlation of our seismic structure with near-surface geology tentatively suggests that contact zones between the EL, Belarus-Baltic Granulite Domain. Central Belarussian Belt (CB), and the Osnitsk-Mikashevichi Igneous Belt all dip slightly to the southeast, consistent with successive docking of these terranes during craton growth;th. A spectacular feature of our model is high velocities throughout the CB crust, which marks the Fennoscandia-Sarmatia suture. Here we observe a change from typical shield/platform crust in the northwest to highly heterogeneous crust with pronounced lower crustal reflectivity in the southeast. Our results are consistent with CB uplift during continental collision. Our model implies significant tectonic involvement of middle crust in the formation of the Pripyat Trough. (C) 1999 Elsevier Science B.V. All rights reserved.