| 释义 |
ˈsea-floor
1. The floor of the sea.
1855Kingsley Glaucus (1878) 60 The variety of its rocks, aspects, and sea-floors. 1922[see outwander v.]. 1946Proc. Prehist. Soc. XII. 24 The seal must have sunk in deep water and come to rest on the sea-floor. 1967Oceanogr. & Marine Biol. V. 317 Two principal dispersal mechanisms affect shelf benthos; these are, (1) shallow seafloor connections and, (2) surface currents. 1981London Mag. July 9 A door slams, a heavy wave, a door, the sea-floor shudders.
2. sea-floor spreading Geol., (the hypothesis of) the formation of fresh areas of oceanic crust, occurring through the upwelling of magma at mid-ocean ridges and its subsequent outward movement on either side.
1961R. S. Dietz in Nature 3 June 854/1 [The concept proposed here, which can be termed the ‘spreading sea⁓floor theory’, is largely intuitive, having been derived through an attempt to interpret sea-floor bathymetry.] Ibid. 856/2 Sea floor spreading obviates this difficulty: continents never move through the sima. 1971Nature 1 Jan. 9/2 The whole of geophysics has been transformed within a few years by the discovery of seafloor spreading. 1977A. Hallam Planet Earth 42/3 If its magnetic signature allowed an age to be assigned to each piece of ocean floor, it was possible to calculate a velocity for sea-floor spreading. |