地質現象と地球化学サイクル : 物質移動からみた地殻の発展形態

概要

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Movement of chemical species within the crust of the earth is described by a concept of geochemical cycle. The dynamical behavior of cycle is studied in which the transfer rates of species among continents, ocean, and ocean bottom play an important role. The cycle is modelnized as the circuit system similar to the electric network. Characteristics of the circuit at the steady state are obtained referring to data of contents of some elements, i. e., Mg, Na, Ca, K, S, and Sr isotopes. Orogenism or the material supply from the mantle to the crust is regarded as the input given to the circuit. Based upon the characteristics thus obtained, the response of the circuit to the impulsive input is discussed. It is concluded that the relaxation time to approach the steady state is less than 200 million years for various reasonable characteristics. Therefore the geochemical cycle tends to become steady before the subsequent orogenism starts of which interval is estimated as several hundred million years from geological information. A few remarks for a further study are also given.
地学団体研究会の論文
1965-09-30