摘要
Over a long period of time, the spreading rate of the mid-Atlantic ridge has been ascertained by the geological age of the magnetic stripe laid out on either side of the mid-ocean ridge in conjunction with the annals of the magnetic reversal history. Is the mid-Atlantic ridge still spreading today? How fast is it moving or are there any changes? All these questions remain unsolved. Based on the newest ITRF2000 velocity field published by the International Earth Rotation Service (IERS), the contemporary global plate motion model ITRF2000VEL is constructed, independent of any plate model hypothesis. Solutions for relative Euler’s vectors of plate pairs as North America-Eurasia, North America-Africa and South America-Africa are obtained, implying current spreading rates of the mid-Atlantic ridge. Comparing them with results from the NNR-NUVEL1A model displays the present-day motion characteristics of the mid-Atlantic ridge that the mid-ridge of the South Atlantic, whose spreading is slowing down, spreads
Over a long period of time, the spreading rate of the mid-Atlantic ridge has been ascertained by the geological age of the magnetic stripe laid out on either side of the mid-ocean ridge in conjunction with the annals of the magnetic reversal history. Is the mid-Atlantic ridge still spreading today? How fast is it moving or are there any changes? All these questions remain unsolved. Based on the newest ITRF2000 velocity field published by the International Earth Rotation Service (IERS), the contemporary global plate motion model ITRF2000VEL is constructed, independent of any plate model hypothesis. Solutions for relative Euler’s vectors of plate pairs as North America-Eurasia, North America-Africa and South America-Africa are obtained, implying current spreading rates of the mid-Atlantic ridge. Comparing them with results from the NNR-NUVEL1A model displays the present-day motion characteristics of the mid-Atlantic ridge that the mid-ridge of the South Atlantic, whose spreading is slowing down, spreads faster than the North Atlantic, whose spreading is speeding up.
基金
This work was supported by the National Key Basic Research Project (Grant No. Gl998040703), the Major Project for Basic Research of the Chinese Academy of Sciences (Grant No. KJ951-1-304)
the Scientific and Technological Development Foundation of Shangh
