Geografie 1971, 76, 38-46
Tectonics and the Pleistocene Glaciation
Climatic changes originating the Pleistocene glaciation and the alternations of glacial and interglacial stages must be considered as to have been caused by factors of factonics and by the activity of planetary origin. We presume the intensified volcanic activity (Casier) increases the CO2-content in the atmosphere, climatic variation being caused by polar wandering and subcrustal flows (Ewing, Donn), or by solar and planetary influence (Fairbridge) etc. Recent conception of isostasy or glacioistasy still finds up-and-down movements of crustal blocks be of external but not of internal origincaused by climatic or erosional processes. At present it is evident already, that vertical movements of the Earth's surface are independent not only on glaciation but also on displacement of weathering products, of erosion and denudation. Pratt's and Airy's laboratory experiments on isostasy did not take into consideration the influence of surrounding conditions but were engaged only in the changing weight of metal blocks floating on mercury. Isostatic movements can be successful in the open air only in laboratory like conditions: the surface of the liquid with floating blocks (of metal, of the Earth's crust) must be entirely calm, the limits (fault planes) of blocks must be plane and smooth, the blocks cannot be pressed on together in no way, etc. Such conditions do not exist in the open air: but only in such "laboratory" conditions isostatic block movements of the Earth's crust could occur. The author of this article is of opinion, that the up-and-down movements of the blocks are induced by tidal oscillations of the Earth's crust and also by sea-floor spreading. The thickness of the continental as well as of the oceanic crust is not uniform; thus the process of underthrusting the continents by oceanic crust must cause irregular upheaval and sinking of individual blocks. In this way we can clear up also the origin of glaciation and the alternation of glacial and interglacial stages. The surface of upward moving blocks gets into the colder strata of the atmosphere and the air temperature above the blocks raises in the case of their sinking. Glaciation can occur only in marginal zones of cold climate belts - there the upheaval of land need not be too high as to be able of cooling the atmosphere needed for the origin of glaciation. Nevertheless the tectonic movement cannot be held for a definitive cause of all these changes - but it seems to be the most important link in the chain of causes, whose continuation one must seek for off the Earth, within the activity of the Sun and other planets.
