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1.
M. L. Kopp V. E. Verzhbitsky A. A. Kolesnichenko T. Yu. Tveritinova N. Yu. Vasil’ev V. A. Korchemagin A. O. Mostryukov A. I. Ioffe 《Geotectonics》2014,48(4):273-291
This paper presents the first cartographic reconstruction of the recent stress field for the southeastern Russian Plate and the southern Urals based on computer analysis of the extensive body of measurements of mesostructural kinematic markers. Comparison of this reconstruction with macro- and mesostructural data on the dynamics of recent dislocations at the platform leads to the following conclusions: (1) spatial variations of the stress field reflect the pressure on the platform’s lithosphere from the Caucasus-Kopet Dagh collisional orogen and the intraplate linear rise of the recent Urals, presumably related to the Central Asian collision zone; (2) when passing through the heterogeneous crust of the platform, the collision stresses were distorted: in the vertical section, compression decreased upward (especially in strike-slip-stress regime) and even gave way to extension above uplifting hanging wall of thrust faults and crests of swells; in plan view, compression (including in the strike-slip-stress regime) increased at basement uplifts; on the contrary, extension increased near syneclises, as well as lateral squeezing directed here along strike-slip faults; (3) reconstructions based on data variable in scale and type (results of macro- and mesostructural observations processed by differing statistical means with leading use of computer programs) do not contradict but supplement one another. Taken together, they represent the complete pattern of the recent stress state; (4) our results can be used for applied purposes to introduce clarity into the kinematics of the known faults, especially for revealing strike-slip offsets and how the intraplate earthquakes relate to faults and flexures of a certain kinematics. In general, they indicate that tectonodynamic analysis is promising for solving regional tectonic problems. 相似文献
2.
Major hypotheses on the formation of the Iceland region are considered. It is noted that plate- and plume-tectonic genesis
is the most substantiated hypothesis for this region. Model estimations of the effect of hot plume on the formation of genetically
different oceanic ridges are obtained. Computer calculations are performed for the thermal subsidence rate of aseismic ridges
(Ninetyeast and Hawaiian-Emperor) in the asthenosphere of the Indian and Pacific oceans. Comparative analysis of the calculated
subsidence rates of these ridges with those in the Iceland region (Reykjanes and Kolbeinsey ridges) is performed. The results
suggest that the thermophysical processes of formation of the spreading Reykjanes and Kolbeinsey ridges were similar to those
of the aseismic Ninetyeast and Hawaiian-Emperor ridges: the genesis of all these ridges is related to the functioning of a
hotspot. Analysis of the heat flux distribution in the Iceland Island and Hawaiian Rise areas is carried out. Analysis and
numerical calculations indicate that the genesis of Iceland was initially characterized by the plume-tectonic transformation
of a continental rather than oceanic lithosphere. The level of geothermal regime near Iceland was two times higher (100 mW/m2) relative to the Hawaiian Rise area (50 mW/m2) because the average lithosphere thickness of the Reykjanes and Kolbeinsey ridges near the Iceland was approximately two
times less (40 km) relative to the thickness of the Pacific Plate (80 km) in the Hawaiian area. The main stages of evolution
of the Iceland region are based on geological and geothermal data and numerical thermophysical modeling. The Cenozoic tectonic
evolution of the region is considered. Paleogeodynamic reconstructions of the North Atlantic in the hotspot system at 60,
50, and 20 Ma are obtained. 相似文献
3.
Golionko B. G. Basilyan A. E. Nikolsky P. A. Kostyleva V. V. Malyshev N. A. Verzhbitsky V. E. Obmetko V. V. Borodulin A. A. 《Geotectonics》2019,53(6):675-699
Geotectonics - Detailed lithological, stratigraphic, and structural studies of the fold-thrust structures were conducted on New Siberia Island. We have established that the jointly deformed... 相似文献
4.
The tectonic structure and anomalous distributions of geophysical fields of the Sea of Okhotsk region are considered; the lack of reliable data on the age of the lithosphere beneath basins of various origins in the Sea of Okhotsk is noted. Model calculations based on geological and geophysical data yielded an age of 65 Ma (the Cretaceous-Paleocene boundary) for the Central Okhotsk rise underlain by the continental lithosphere. This estimate agrees with the age (the end of the Cretaceous) derived from seismostratigraphic data. A comparative analysis of theoretical and measured heat fluxes in the Akademii Nauk Rise, underlain by a thinned continental crust, is performed. The analysis points to a higher (by 20%) value of the measured thermal background of the rise, which is consistent with a high negative gradient of gravity anomalies in this area. Calculations yielded an age of 36 Ma (the Early Oligocene) and a lithosphere thickness of 50 km for the South Okhotsk depression, whose seafloor was formed by processes of backarc spreading. The estimated age of the depression is supported by kinematic data on the region; the calculated thickness of the lithosphere coincides with the value estimated from data of magnetotelluric sounding here. This indicates that the formation time (36 Ma) of the South Okhotsk depression was estimated correctly. Numerical modeling performed for the determination of the basement age of rifting basins in the Sea of Okhotsk gave the following estimates: 18 Ma (the Early Miocene) for the Deryugin basin, 12 Ma (the Middle Miocene) for the TINRO basin, and 23 Ma (the Late Oligocene) for the West Kamchatka trough. These estimates agree with the formation time (Oligocene-Quaternary) of the sedimentary cover in rifting basins of the Sea of Okhotsk derived from geological and geophysical data. Model temperature estimates are obtained for lithologic and stratigraphic boundaries of the sedimentary cover in the Deryugin and TINRO basins and the West Kamchatka trough; the temperature analysis indicates that the latter two structures are promising for oil and hydrocarbon gas generation; the West Kamchatka trough possesses better reservoir properties compared to the TINRO and Deryugin basins. The latter is promising for the generation of hydrocarbon gas. Paleogeodynamic reconstructions of the Sea of Okhotsk region evolution are obtained for times of 90, 66, and 36 Ma on the basis of kinematic, geomagnetic, structural, tectonic, geothermal, and other geological and geophysical data. 相似文献
5.
E. V. Verzhbitsky L. I. Lobkovsky M. V. Kononov A. F. Byakov 《Izvestiya Physics of the Solid Earth》2012,48(11-12):785-797
An insufficient number of dated native samples and indistinct magnetic anomalies in the Amerasian Basin prevent geophysicists from identifying the exact age of most of its structural elements. Due to this, it is impossible to gain an insight into the evolution of this vast region, which is highly promising in terms of its hydrocarbon potential. Therefore, the geological time of the formation of the structural elements composing the Amerasian Basin is determined either hypothetically or very loosely (for example, Late Cretaceous-Cenozoic). In order to more precisely estimate the time of formation of the structural elements within the Amerasian Basin, we applied the geothermal method, which is highly informative in terms of the age of the lithosphere, its thickness, and the evolution of the basin structures. Besides, this method provides far narrower time constraints for the formation of the structures compared to the geological data. Based on the thermal flow data, we have numerically calculated the age of the structural elements composing the Amerasian Basin: Podvodnikov Basin (97?C79 Ma), Makarov Basin (75?C61 Ma), Alpha-Mendeleev Ridge (97?C79 Ma), and Lomonosov Ridge (69?C57 Ma). The age of these structures derived from the geothermal data agrees with the estimates determined from the geological, geomagnetic, seismic, and radiometric data. Based on the age of the structures estimated from the thermal flow data and the analysis of the geological and geophysical evidence, conclusions are made concerning the genesis and character of formation of the Podvodnikov and Makarov basins and the Alpha-Mendeleev and Lomonosov ridges within the Amerasian Basin. 相似文献
6.
Verzhbitsky E. V. Lobkovsky L. I. Kononov M. V. Byakov A. F. 《Izvestiya Physics of the Solid Earth》2012,48(11):785-797
An insufficient number of dated native samples and indistinct magnetic anomalies in the Amerasian Basin prevent geophysicists from identifying the exact age of most of its structural elements. Due to this, it is impossible to gain an insight into the evolution of this vast region, which is highly promising in terms of its hydrocarbon potential. Therefore, the geological time of the formation of the structural elements composing the Amerasian Basin is determined either hypothetically or very loosely (for example, Late Cretaceous-Cenozoic). In order to more precisely estimate the time of formation of the structural elements within the Amerasian Basin, we applied the geothermal method, which is highly informative in terms of the age of the lithosphere, its thickness, and the evolution of the basin structures. Besides, this method provides far narrower time constraints for the formation of the structures compared to the geological data. Based on the thermal flow data, we have numerically calculated the age of the structural elements composing the Amerasian Basin: Podvodnikov Basin (97–79 Ma), Makarov Basin (75–61 Ma), Alpha-Mendeleev Ridge (97–79 Ma), and Lomonosov Ridge (69–57 Ma). The age of these structures derived from the geothermal data agrees with the estimates determined from the geological, geomagnetic, seismic, and radiometric data. Based on the age of the structures estimated from the thermal flow data and the analysis of the geological and geophysical evidence, conclusions are made concerning the genesis and character of formation of the Podvodnikov and Makarov basins and the Alpha-Mendeleev and Lomonosov ridges within the Amerasian Basin.
相似文献7.
The Tulva Upland is a meridional neotectonic swell that complicates the eastern Russian Plate in its recent manifestation. The intense recent uplift is expressed in the rise and splitting of terraces of the Kama River and anomalously increasing lateral ruggedness of topography. Having a steep western and a gentle eastern limb, the swell is sharply asymmetric in cross section and additionally is complicated by a chain of local NE-trending uplifts. Several morphostructural indications testify to the substantial role of NW-trending strike-slip faulting in the structure of the swell, which was formed under conditions of latitudinal compression and conjugated meridional extension. Such a stress-strain field is confirmed by the study of mesotectonic structural elements in the western steep limb of the swell regarded as a flexure above a suggested reverse fault. Like many other zones of within-plate dislocations in the Russian Plate, the recent Tulva Swell was formed as a result of folding of sedimentary fill and inversion of long-lived platform trough. In our case, this trough inherited the Riphean Kaltasy Aulacogen. Together with the unilateral, probably, reverse-fault-line (?) Ufa Horst, the Tulva Swell is situated opposite to the area of maximum near-latitudinal compression of the recent Urals (the socalled Ufa amphitheater, or Central Ural pinch) and along with other within-plate arches similar in structure—Bugul’ma-Belebei and Obschii Syrt—marks a zone of neotectonic reactivation of the Russian Plate near the Urals. 相似文献
8.
Geophysical data on the northern part of the Pacific Ocean were systematized to compile a map of geomagnetic and geothermal studies of the Bering Sea. The absence of reliable data about the formation time of the Bering Sea structures of oceanic and continental origins is noted; this hampered the assessment of the geodynamical processes in the North Pacific. Based on the geophysical data, we estimated the age of the structures of the Bering Sea floor such as the Commander Basin (21 My), the Shirshov Ridge (95 and 33 My in the northern and southern parts, respectively), the Aleutian Basin (70 My), the Vitus Arch (44 My), the Bowers Ridge (30 My), and the Bowers Basin (40 My). These values are confirmed by the geological, geophysical, and kinematic data. A numerical modeling of the formation of extensive regional structures (Emperor Fracture Zone, Chinook Trough, and others) in the Northern Pacific is carried out. A conclusion was made on the basis of the geological and geothermal analysis that the northern and southern parts of the Shirshov Ridge have different geological ages and different tectonic structures. The northern part of the ridge is characterized by an upthrust-nappe terrain origin, while the southern part has originated from a torn-away island arc similar to the origin of the Bowers Ridge. The sea floor of the Aleutian Basin represents a detached part of the Upper Cretaceous Kula plate, on which spreading processes took place in the Vitus Arch area in the Eocene. The final activity phase in the Bering Sea began 21 My B.P. by spreading of the ancient oceanic floor of the Commander Basin. Based on the age estimations of the structures of the Bering Sea floor, the results of the modeling of the process of formation of regional fracture zones and of the geomagnetic, geothermal, tectonic, geological, and structural data, we calculated and compiled a kinematic model (with respect to a hot spot reference system) of the northern part of the Pacific Ocean for 21 My B.P. 相似文献
9.
10.
Maps of the principal structures and geological-geophysical knowledge for the Azores-Gibraltar and Icelandic regions have
been made. The geodynamic conditions of the Azores archipelago formation have been analyzed. It has been noted that the uplifting
of the Azores plume (as well as the Icelandic one) might have been triggered by near-surface tectonic processes. The computer
modeling has been performed with respect to the coefficients of the geodynamic sinking rates for the Azores fragment of the
Mid-Atlantic Ridge. Based on the modeling results, this rate was ∼1.5 times higher than the average sinking rate for the mid-ocean
ridges of the World Ocean in general. The high sinking rate of the Azores fragment is caused by the influence of the plume
material on the sinking process. Based on the complex analysis of the seismicity, thermal flow, and seismic tomography data
distribution, as well as the implemented numerical calculations, the European (northern) part of the diffuse boundary between
the Eurasian and African plates has been identified for the first time. Along with the African (southern) boundary, it outlines
the identified by the authors West Mediterranean plate. 相似文献