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Title :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
Title alternative :Numerical Experiment of Rising of Ultramafic and Mafic Rocks by Squeezing
Authors :林, 大五郎
Authors alternative :Hayashi, Daigoro
Issue Date :30-Sep-1980
Abstract :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 KIZAKI (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.
深成岩の上昇に関して,それらの成因上2つの機構が考えられる.1つは酸性岩,すなわち密度2.67g/cm^3の花崗岩や2.76g/cm^3のミグマタイトなどの,浮力による上昇であり,他は,超塩基性ないし塩基性岩,すなわち密度3.23g/cm^3のカンラン岩や2.98g/cm^3のハンレイ岩などの,しぼり出しによる上昇である.浮力による上昇機構はRAMBERG(Gravity,Deformation and the Earth's Crust, Academic Press, 214p, 1967)やKIZAKI(J. Fac. Sci. Hokkaido Univ., Ser. 4, 15, 157, 1972)らによってすでに提案されているが,しぼり出し上昇の機構に関する検証はまだない.しぼり出しとは,深成岩―周囲岩体より重い―があるとき,その深成岩が周囲岩体の圧力によってしぼり出されることを意味する.本論文では,この深成岩のしぼり出しによる上昇を,数値的にシミュレートした.
Type Local :雑誌掲載論文
ISSN :0085-7289
Publisher :国立極地研究所
URI :http://hdl.handle.net/20.500.12000/2907
Citation :南極資料 Vol.70 p.15 -24
Appears in Collections:Peer-reviewed Journal Articles (Faculty of Science)

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