Two mechanisms for the rising of plutonic rocks in terms of their origins are plausible. One is the rising resulted from the buoyancy of acid plutons, e. g. granite and migmatite which are lighter in density, being 2.67 and 2.76 respectively. The other is the rising due to the squeezing of mafic and ultramafic plutons, e. g. peridotite and gabbro which have heavier densities of 3.23 and 2.98 respectively. There has been no verification for the mechanism of squeezing so far, though the mechanism by buoyancy has already been proposed by such authors as RAMBERG (Gravity, Deformation and the Earth's Crust, Academic Press, 214p, 1967) and KlZAKI (J. Fac. Sci. Hokkaido Univ.,Ser. 4, 15, 157, 1972) and others. The term squeezing signifies that when a pluton is heavier than its surrounding rocks (crust), the pluton is squeezed out by the pressure of the surrounding rocks. The rising of pluton by squeezing is demonstrated numerically by a computer simulation in the present paper.
超塩基性および塩基性岩体の「しぼり出し上昇」の数値実験
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KJ00002477243
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概要
