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The theoretical bases of the structural-paragenetic method for the reconstruction of geodynamic environments are critically analyzed in view of ideas about nonlinear dynamics and the coarse discrete fractality of the geological medium. The work shows the incorrectness of reconstructions without considering bifurcations of structurization and its strong dependence on differences in initial conditions, the unreliability of recognizing particular parageneses of different ages, types, and ranks, as well as that without immediate observational and experimental examination of the conformity of reconstructions to the real environments of the geological past. 相似文献
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Doklady Earth Sciences - For the first time, a series of long-term taphonomic experiments (1–5 years) has shown iron deposition during the formation of fossils of soft-bodied animals. Based... 相似文献
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It is shown that the main problem in earthquake prediction consists not in separating a useful signal on an imminent strong earthquake from noise but in determining the character of the signal itself. The signal, due to the fractal and roughly discontinuous nature of the geological medium, is not an isolated precursor anomaly but always presents a host of varied-rank wavelets that are not distinctly recognizable and, in addition, are fluctuating in their amplitudes and duration. Bifurcation and the extreme dependence of the behavior of nonlinear geological system upon initial and continuously variable current conditions explain the inevitable unreliability of predicting the most mature earthquake sources. 相似文献
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The pursuit of geocataclysm prediction is stimulated by aprioristic confidence in the idea that it can be in principle achieved. This means that small variations in the conditions of the course of a process should generate predictably small variations in its result. In reality, only the following aspects can be predicted: the character of a process as a whole and that of its separate stages; attractor type; and the scenarios of its transition from stage to stage. However, successful predictions of particular events are rare because of the extreme dependence of nonlinear geological systems on variations in initial conditions. Precursors exist, but their efficiency is unpredictably irregular. The rare successes of predictions can be attributed to the weak requirements for forecasts and their examination, as well as to random coincidence with reality. 相似文献
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N. V. Koronovsky G. V. Bryantseva M. A. Goncharov A. A. Naimark A. V. Kopaev 《Geotectonics》2014,48(2):151-162
The meaning of the term lineament, the modes of their recognition, and the lineament patterns dramatically varying in interpretations by different authors, are considered. It has been shown that obligatory identification of lineaments with faults and fracture zones is mostly implied rather than corroborated by evidence. The mapping of faults in platform regions based on lineaments requires distinct geological substantiation, otherwise lineament patterns remain devoid of sense. The regmatic system of supposedly tectonic dislocations cannot form on the surface of the rotating Earth, because the operating forces are too weak. Taking into account drift of continents and their rotation in the geological past, one hardly can speak of an ancient and inherited fault network. 相似文献
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It is shown that dynamic geology as a fundamental synthesizing doctrine about geological processes is passing from a paradigm
of linearity, inductivity, empiricism to a paradigm of nonlinearity and a hypothetic-deductive method of cognition. This is
accompanied by a radical reorganization of the methodological bases of the doctrine. 相似文献
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A. A. Naimark 《Moscow University Geology Bulletin》2009,64(5):273-280
Analysis of nonlinear processes of tectonic fracturing reveals a fundamental problem of physical modeling of dislocations and stresses in the Earth’s crust. A structure assigned in experiments and simulating the appearance and development of dislocations does not have the self-organized coarsely discrete fractal structure of the natural geological environment, i.e., self-similarity between units, into which it is divided. A fractal structure initially assigned would produce an extremely unstable modeling result, whose probability of similarity with one actually occurring among those theoretically possible tends to zero. 相似文献
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McKenzie's model of sedimentary basin evolution and its modification, widely used in geophysics, sometimes fails to explain discrepancies between predicted and observed values of extension, thinning and subsidence of the Earth's crust, as for the North Sea. We develop a numerical model of sedimentary basin evolution based on the mechanism suggested by Lobkovsky. In the course of rifting, accompanied by thinning of lower parts of the lithosphere, the roof of the underlying asthenosphere moves upward. the material of the mantle lifts and partially melts owing to the reduction of pressure. the density difference between the melt and the crystalline skeleton results in the filtration of the lighter melt and its accumulation in the form of a magmatic lens. Due to changed P-T conditions, the material of the lens undergoes the gabbro-eclogite phase transformation. the resultant anomalously heavy eclogite lens sinks in the surrounding material. This induces a viscous flow, changing the surface topography and forming a sedimentary basin. We construct a 2-D numerical model describing a viscous flow induced by subsidence of a heavy body and compute changes of surface topography. to compute the flow we employ the Galerkin-spline approach, with modifications allowing for density discontinuities and time dependence of the phase transformation. We apply the model to the cases of the Illinois, Michigan and Williston basins. the computed and tectonic subsidence curves agree well for these cases. the proposed model is compatible with the seismic structure of the crust and upper mantle below these basins. the model is also consistent with gravity data. the approach is applicable to other intracratonic basins. 相似文献
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V. A. Eroshchev-Shak G. A. Karpov B. P. Zolotarev E. B. Naimark E. I. Kompantseva 《Journal of Volcanology and Seismology》2010,4(6):385-395
The conditions of transformation of the primary material of extrusive rocks and the synthesis of secondary products during
post-eruptive processes have been considered using the example of three large areas of presentday volcanism and hydrothermal
activity in Kamchatka, viz., the Great Tolbachik Fissure Eruption of 1975–1976 (GTFE), the Karymskii Volcanic Center (eruption
of 1996 in Lake Karymskii), and the Uzon volcanic-hydrothermal system. Post-eruptive transformation of rocks causes volcanic-hydrothermal
lithogenesis and low-middle-temperature mineralization in areas of present-day contrast (basalt-andesite) volcanism in zones
of crustal extension. Based on the permanent presence of a wide range of acid rocks, such as dacites, rhyolites, and pumices
in the areas of Holocene basalt volcanism of Kamchatka, we concluded that in conditions of pre-rift crustal extension, acid
volcanism is preceded by deep-seated differentiation (similar to liquation) of primary mantle melts with separation of fluids
enriched in ore-forming elements, first of all Cu, Zn, Pb, As, Sb, and Hg. During volcanogenic-hydrothermal lithogenesis in
the discharge areas of those fluid systems, the destruction and replacement of primary minerals of igneous rocks and formation
of complex-composition metasomatites take place. Clay minerals are major components of metasomatites in subaqueous conditions.
The role of microbiota in processes of volcanogenic-hydrothermal lithogenesis and occurrences of local mineralization was
studied. 相似文献
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