| 释义 |
sea-floor spreading
sea-floor spreading (sē′flôr′)n. In the theory of plate tectonics, the process by which new oceanic crust is formed by the convective upwelling of magma at mid-ocean ridges, resulting in the continuous lateral displacement of existing oceanic crust.sea-floor spreading (ˈsiːˌflɔː) n1. (Geological Science) a series of processes in which new oceanic lithosphere is created at oceanic ridges, spreads away from the ridges, and returns to the earth's interior along subduction zones. Also called: ocean floor spreading sea-floor spreading
sea-floor spreading[′sē ¦flȯr ‚spred·iŋ] (geology) The hypothesis that the ocean floor is spreading away from the midoceanic ridges and is being conveyed landward by convective cells in the earth's mantle, carrying the continental blocks as passive passengers; the ocean floor moves away from the midoceanic ridge at the rate of 0.4 to 4 inches (1 to 10 centimeters) per year and provides the source of power in the hypothesis of plate tectonics. Also known as ocean-floor spreading; spreading concept; spreading floor hypothesis. |