摘要
基于地球内部结构模型 (EISEM) ,建立了一个模型 (IAMTM)来模拟地球早期绝热压缩过程中的地球内部角速度的转移。计算的时间范围是从地球吸积完成开始 5Ma。改变不同的参数 ,模型得出结论 ,当t=1 85Ma时 ,由于地心引力不稳定性 ,地球外层的熔融层从地球赤道甩出。抛射过程持续了 0 0 5～ 0 15Ma ,抛射出的物质质量为 1 2～ 2 5M0 (M0 是现在的月球质量 ) ,这些物质碎片相互碰撞聚集逐渐在Roche极限附近形成月球。随着物质分异和地核的逐渐增大 ,地球的半径在抛射后减小到最小值 (R =5 0 75 16km)。随着潮汐摩擦力和地球体积的增大 ,地球自转角速度变慢。 2Ma后地球和月球之间的距离增大到
Based on the Earth's internal structure evolution model(EISEM), we have built a model to simulate the earth's internal angular momentum transfer during its early adiabatic compression process(IAMTM). The time scale of this calculation is 5 Ma starting at about the completion of the earth's accretion. Running a variety of parameters, our modeling results show that when t =1 85 Ma, owing to its gravity instability, the Earth's liquid outlayer is spun off from equator. This ejection lasts 0 05～0 15 Ma and the mass of ejected material is 1 2～2 5 M 0 ( M 0 is the present mass of the moon) which condenses quickly and generates debris disk gradually. Near the Roche limit the moon is produced from debris disk. The Earth's radius is reduced to its minimum value ( R =5 075 16 km) after this ejection. With material differentiating and core growing, the volume of the earth aggrandizes gradually. Because of tidal friction and aggrandizement of the earth's volume, the earth's rotation angular velocity slows down. Two Ma later, the distance between the earth and the moon rises to about 3 Roche radius
出处
《地学前缘》
EI
CAS
CSCD
2002年第3期31-40,共10页
Earth Science Frontiers
基金
国家"九五"攀登计划 (SSERIVI)
教育部骨干教师计划 (K0 0 0 110A)
