Summary Magnetic method is effective, rapid, and cheap technology in the geophysical studying of hydrocarbon fields. The present study related to the investigation of the Rubaniv gas field in the Outer zone of the Carpathian Foredeep. Our previous results demonstrated the close dependence of the local anomalous magnetic field upon gas deposit of Rubaniv field, soil magnetic susceptibility of the genetic horizons, and possible gas microseepage. New results are concentrated in magnetic mineralogy of soils from the areas of hydrocarbons impact as well as natural patches. The genesis of soil mineral magnetism deals with iron oxides, hydroxides, and sulphides. We identified natural magnetite, hematite, goethite, maghemite and paramagnetics formation in both soils from the hydrocarbon impacted areas as well as from the natural forest area. The hydrocarbon genesis of the soil magnetics within oil and gas fields suggested by the presence of iron sulphides, oxidation of pyrite, transformation of the antiferromagnetic hexagonal pyrrhotite into ferromagnetic monoclinic pyrrhotite.
Summary A close correspondence has been established between different-ranked tectonic lineamentous structural plans: the Black Sea basin/region, on the one hand, and the Mediterranean mobile belt as a whole, on the other. This indicates the coherency of faults and fault zones within the entire Mediterranean – both within the sea areas and the continental surroundingds. The structural position of the Black Sea basin as a whole is determined by its location at the intersection area (superposition, interference) of the diagonal (subdiagonal) transcontinental tectonic lineamentous belts: the north-west – Baltic-Iranian (Elba-Zagros), Caucasus-Kopetdag, and the north-east – Atlas- Black Sea. The absence of large-scale lateral displacements at the intersection nodes of differently oriented supermegalineament systems indicates the relative autonomous stationarity and inheritance of the formation of the lyneament framework during the entire Mezozoic-Cenozoic and relatively low-shear nature of its realization. This feature of the Black Sea region structural pattern significantly limits the possibility of using neomobilistic geodynamic models to explain the history of the geological development of the region. The strict consistency and orderliness of the lineament framework can be ensured only by global planetary factors associated with the influence of the rotational regime of the Earth’s shells on the stress distribution in the lithosphere.
Summary To compute the phase velocities in the weakly anisotropic media, we propose to transform the Christoffel matrix into an adapted coordinate system, and, then, apply the perturbation theory to the resulting matrix. The diagonal elements of the resulting matrix are initial approximations of the phase velocities squared. To refine them, it is proposed to use either iterative schemes or Taylor series expansions. To approximate the phase velocities of the S1 and S2 waves, a stable method is proposed based on solving a quadratic equation with the coefficients being expressed in terms of the matrix elements and the precomputed value of the qP wave phase velocity squared. The computational accuracy is demonstrated for the standard orthorhombic model.
Summary The research aim was determination of the inner structure and kinematics of the Sushchany-Perga fault zone of the western part of the Ukrainian Shield. For investigation of fracturing and structural-textural elements of rocks the structural-paragenetic method of tectonophysics was used. It was determined that formation of the Sushchany-Perga fault zone continued during at least five phases of deformation. They were accompanied by the formation of differently oriented shear zones: Khmelivka, Sushchany, Perga, Rudnia-Khochin, Lopatychi. The Khmelivka and Sushchany shear zones are similar to striking of the Nemyriv and Khmelnik fault zones of the Ukrainian shield, which belong to the Nemyriv stage of faulting (∼ 1.99 Ga). The Rudnia-Khochin and Perga phases are related to the fact that the Sushchany-Perga fault zone was quite active during the junction of the Fennoscandia and Sarmatia microplates. We have established that the development of thrust fault and normal downthrow fault type shears, which took place in an environment of compression and extension, respectively, is associated with the formation period of the Perzhan granitoids complex (1.801.70 Ga). This alternation of the compression and extension conditions entailed resulted in the ore occurrences and deposits formation within the Perga tectonic joint.
Summary The generalization and cadastral systematization of data on the Nikolaevskii manifestation of scheelite mineralization (Right-Bank Region of the Ukrainian Shield) were made. The cadastral data regarding the Nikolaevskii wolframite mineralization are grouped in four tables. In total, 43 cadastral attributes are determined: 11 cadastral attributes – in relation to spatial characteristics of mineralization; 18 cadastral attributes – in relation to geochemical peculiarities; 9 cadastral attributes – in relation to mineralogical description of scheelites; 5 cadastral attributes – in relation to chemical and X-ray identification of scheelites. The peculiarities of the scheelite mineralization of the Nikolaevskii area: 1) localization in the rocks of the Zelenorichenska suite of the Ingulo-Inguletsk series (Lower Proterozoic); 2) linear-lenticular form of tungsten anomalies and zonal character of anomalies of small metals; 3) direct correlation of tungsten with CaO and Na2O in rocks; 4) presence of transverse zonality of mineralization – W, (Mo, Bi), Ag, (V, Cu, Sn), Zn; 5) stratiform sulfide-scheelite with molybdenite type of mineralization; 6) practically pure composition of scheelite individuals (no impurities); 7) association with pyrite, pyrrhotite, chalcopyrite, molybdenite, magnetite, apatite, leucoxene; 8) removal of barium from tungsten-bearing zones and surrounding areas.
