地壳均衡与海平面变化

提要:在全球海面变化的近期研究中，无论是均衡模式、还是重力模式，写考虑到冰川均衡作用和水力均衡作用。本文认为，绝对均衡表示地壳均街的最终结果，相对均衡表示地壳均衡中一系列中间过程。这两种均衡之间的差别，往往被人们所忽视。
    定量计算的结果表明，冰盖的吸引不仅使周围的海面升高，而且使内核在外核中产生定向运动。由于参加相对均衡的大陆壳数量不同、宕石圈的强度不同，陆壳与陆充、陆克与洋壳之间将产生不同幅度的垂直运动。这为解释全球海面变化不一致性提供了另一个新思路。
   

THE ISOSTASY AND THE CHANGE IN SEA LEVEL

By the recent models of change in sea level, glacio-isostasy and hydro-isostasy have been considered. This paper presents the concept of absolute isostasy and relative isostasy. The first represented the final result of isostasy,and the last represented the mid process of isostasy. Absolute isostasy is the relationship between the crust of the glacier and the crust of the ocean. The simple model was presented by A. L. Bloom(1967) , W. E. Farrell and J. A. Clark(1976) present that the gravitational attraction of an ice mass upon a nearby ocean tends to hold sea level high in the vicinity of the ice. This extra load near the ice may have a significant influence on postglacial isostatic adjustment. The result of my research is that the gravitational attraction of an ice mass and the extra load of water near the ice tends to make the core move. All of these can change the geoid and the sea level. It may be a bridge between the Clark' s isostasy model and Morner' s gravitation model. Suppose we extract a mass M,representing an ice sheet,from the ocean (it caused a uniform fall 130m in sea level) ,and locate M as a spherical cap of radius B (woodward, 1888). The mass M of the spherical cap is different in gravitational attraction from the mass M of a point on the Earth' s surface. In the first case,the mass M can make the core move 1. 2km and it caused the Maximal differentia 3. 89m of the change in sea level. For the relative isostasy, the crust of continent near the ocean will join the glacio-isostatic adjustment. The pinnacle islands is not a dipsticks, because the change in sea level upon melting of the ice and filling of the ocean would not be uniform and the isostatic adjustment in the whole earth can not take place at the same time.