他の惑星における火山現象

抄録

An accretional energy of a growing terrestrial planet produces at least partial melting in the upper silicate layer of a few hundred kilometers, which is called the magma ocean, when the mass of the growing body exceeds that of the Moon (about 8×10²²kg). Various topographic characteristics among terrestrial planets can be understood by the relative importance of factors governing the cratering, volcanic, tectonic, and erosion/sedimentation processes. Modes of volcanisms that produce differences of the surface topography are (1) plate recycling, (2) hot spots and (3) flood basalt flows, depending upon various cooling processes of the magma ocean. Relative amounts of the heat loss from a planet through each mode of volcanisms are estimated mainly from topographic features of terrestrial planets by referring modes of the heat loss from the earth. It is suggested that the flood basalt flow would play an important role at some stage in the heat loss budget of Venus, Earth, Mars and probably Moon. Varieties of modes of the heat loss among terrestrial planets can be interpreted by difference in the thermal history that may reflect to volcanic features together with the lithospheric thickness, surface topography and gravity, and other characteristics.