Współczesne ruchy skorupy ziemskiej w świetle nowej tektoniki globowej

Witold Cezariusz Kowalski



In accordance with the principle of actualism, studies on the nature and character of recent crustal movements make it possible to determine character and origin of neo- and paleotectonic movements and, therefore, correct reconstructions of paleogeographic conditions. Recent movements of the Earth crust should be treated asexternal expression of its actual state and dynamics, and their concordance with requirements of the theory of global tectonics would convincingly show validity of the latter. The paradigm of the global (plate) tectonics, its origin and actual state are discussed along with reservations put in relation to this theory. With reference to the W.C. Kowalski (1978) concordance and discordance model it is emphasized that the displacement recorded at the Barth surface is the net result of displacements of a whole (or a part of) crustal block bounded by deep crustal fractures, as well as individual displacements taking place in various depth zones - stages - in the block (Figs 1, 2), relatively independent of movement of the block as a whole. The accepted methods of correcting measurement errors are shown to be a potential and actual source of errors in maps of recent crustal movements and kinematic characteristics of a given part of the Earth crust (Fig. 3). It is also shown that the treatment of velocities established in different areas and time intervals as simultaneous changes real image of differentiation of movements of individual crustal blocks in a given movement (Fig. 4) and obscures real image of the state of stresses and their relaxation in the lithosphere, which appears varying in time. The detailed analysis of relations between recent movements of the Earth crust and its Precambrian, Caledonian, Variscan and Alpine structures in the area of Poland showed that the former represent a continuation of those acting in the geological past (16, 19, 20, 25). The movements are characterized by definite development trends in a given time interval and by repeated changes of the periodic or quasiperiodic type of various order (17) in such time interval. The finding the degree in which the presently measured movements reflect prolonged trends and in which - periodic or quasiperiodic movements, is one of major questions in modem geodynamics. For appropriate solution of the above questions it seems necessary to carry out further, more accurate and numerous, preferably continuous measurements, always made with reference to the identified geological structures and on the basis of geophysical studies. The surveys should involve evaluation of real values of tectonic component of the measured movement of the Earth surface and, at the same time, elimination of all the atectonic components, i.e. the noise obscuring actual movement of a plate or lithospheric blocks.

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