マントルからの流体の熱的影響と九州中部地域の地殻熱構造について

Abstract

The physical basis of the thermal model comprising the mechanism of filteration of mantlefluids has been investigated and then it has been suggested that this model can be utilized onlyin such cases that the earth's crust is characterized by sufficiently high permeability of the rocks.The filteration mechanism was offered as a possible explanation of the extremely high valuesof surface heat flow observed in central Kyushu, especially in the volcanic and geothermal area, where deep-seated faults like the Oita-Kumamoto tectonic line and differential block-movementalong them have played a leading role in the late Cainozoic geological history, implying highpermeability of the crustal rocks. On the other hand, it was noticed that this mechanism couldnot be responsible for thermal processes accompanied by extensive folding of the crust, suchas regional metamorphism at the inversion stage of geosynclinal development, since in this casethe filteration of mantle fluids is restricted by low permeability of the rocks, which rather bringsabout some advective motion of the crustal layers as manifested by folding.