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Geomorphological Techniques in Neotectonics Studies: Sources of Potential Uncertaintiesтезисы доклада
- Автор: Varuschenko S.S.
- Сборник: Gradualism vs catastrophism. IAG Regional conference. Extended abstracts
- Тезисы
- Год издания: 2015
- Место издания: Publ.House of Altay State Univ Barnaul
- Первая страница: 213
- Последняя страница: 213
- Аннотация: Data on amplitudes and rates of neotectonic movements are used in tectonic geomorphology studies, natural hazard forecasting (seismic zoning), prospecting of mineral resources, etc. Major methods of estimation of neotectonic movements rates and amplitudes include topographic analysis of river terraces and planation surfaces, analysis of thickness and grain size of deposits correlative to denudation processes during the neotectonic epoch. Acceleration of erosion and denudation in the end of Cenozoic is usually considered to be the result of accelerated tectonic uplift. In this paper, it is shown that the above techniques do not account for the effect of palaeo-landscape geometry on denudation in a given time moment. Transformation of this geometry through time results in non-linearity of the erosion rate dependence on tectonic uplift rate. It follows from a non-linear increase of the surface area of a mountain terrain and, consequently, river catchments, under constant tectonic uplift rate. Catchment area determines river sediment load and amount of sediments transported out of mountain terrain. Also, terrain uplift enforces air mass convection and non-linear increase of atmospheric precipitation. Therefore constant tectonic uplift results in non-linear increase (acceleration) of two independent factors that govern erosion. Acceleration of erosion under constant uplift may be exhibited in river terrace patterns, thickness and grain size of correlative deposits. All these indicators may not reflect any changes of tectonic regimes. Given the above, neotectonic movement rates in many regions may be re-evaluated and corrections can be made in general concepts of lithospheric development, actual seismic zoning, mineral resources prospecting strategy, etc.
- Добавил в систему: Варущенко Сергей Станиславович