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一个改进的地球圈层差异旋转模型
引用本文:王心源 张喜慧. 一个改进的地球圈层差异旋转模型[J]. 高校地质学报, 2000, 6(4): 561-565
作者姓名:王心源 张喜慧
作者单位:1. 中国科学院 遥感信息科学开放实验室,北京 100101;2. 南京大学 地球 科学系、内生金属矿床成矿机制研究国家重点实验室,江苏 南京210093;3. Center for Earthquake Research ad Information, University of Memphis,U.S.A;4. Dept.of Earth Sciences, University of Yaounde, Cameroon
基金项目:国家自然科学基金!(49972 0 6 9),安徽省教委自然科学资金!(99LJ83),西南石油学院和北京地质力学所国家重点实验室基金资助项目
摘    要:地球自转速度在长期的减慢,而内核自转 又较其外部的地球部分转动快,这是由日 、月对地球的潮汐摩擦引起的同一动力学背景下导致的相关现象。通过能量守衡的定量分析 ,得出地球潮汐耗散能的11% 即可导致内核自转较其外部的地球部分自转快的结论。通过推 理比较和定量分析,提出了岩石圈层、主地幔圈层与内核三个圈层的差异旋转模型:岩石圈 自转速度<主地慢自转速度<内核自转速度。它可能是导致大陆向西飘移-板块构造及地磁产 生的重要机制之一。

关 键 词:潮汐能 大陆 向西飘移 板块构造 地球PREM模型
收稿时间:2000-12-20
修稿时间:2000-03-03

A Developmental Differential Rotation Model of the Earth Layersphere
WANG Xinyuan ,SUN Yan,ZHANG Xi hui ,Richard Ghogomu Tanwi ,YANG Zhao zhu. A Developmental Differential Rotation Model of the Earth Layersphere[J]. Geological Journal of China Universities, 2000, 6(4): 561-565
Authors:WANG Xinyuan   SUN Yan  ZHANG Xi hui   Richard Ghogomu Tanwi   YANG Zhao zhu
Affiliation:1. Laboratory of Remote Sensing Information Science, Chinese Academy of Science, Beijing 100101; 2.Department of Earth Sciences and State Key laboratory for Mineral Deposits Research, Nanjing University, Nanjing 21O093; 3. Center for Earthquake Research and Information, University of Memphis, U.S.A; 4. Department of Earth Sciences, University of Yaounde, Cameroon
Abstract:Using seismological methods, Song and Paul[1] demonstrated that the rotation of the inner core is faster than the daily rotat ion of the mantle and cr ust. This discovery revealed a noticeable phenomenon that the earth's rotatin g rate is getting slow and the inner core' s rotation is faster than that of the crust and the mantle. They are correlative phenomena of the same dynamic backgr ound. We suggest that the phenomenon is the result of the different tidal fricti on primarily from the moon and the sun.  Tidal function might play a very important role in crust evolution, but the succ essful research in the filed is very little till now[8]. Applying the l aw of conser vation of energy can do quantitative analysis. The losing kinetic energy of the crust and the mantle in its long-range slowing rotating may be balanced by the share of dissipated tidal energy in the earth. When calculating the loss of the kinetic energy in the earth, we introduce the prevalent PREM model and quote the parameters h(depth)and ρ (density). From rotary energy (E) formul a E=(1)/(2)Iω2t, where ωt is rotary angular velocity at t moment, I is rotary inertia, we get ΔE exp ression: ΔE≈Iω0Ωt Where ΔE is loose d rotary energy in t time, ω0 is the beginnin g (t=0) angular velocity, Ω is rotary angular acceleration. Let the total mass of the mantle and crust be 4.10×1024kg, calculating that I≈1. 13×1037kg*m2 (see Table 1), we can see that ΔE≈4.53×1011J , when t=1 second.  Lambeck (1980) thought that dissipated tidal energy in the total earth equals 4.0×1012J*s-1 is suitable. If the slowing of the earth's rotatio n is mainly gi ven by tidal friction of earth tidal and ocean tidal, let t=1second, then ΔE is 11 percent of the total dissipated tidal energy in the Earth. The dis sipated tida l energy in the solid inner core is very small. The tidal friction effect is dif ferential from the earth's surface to the core. Because the liquid outer core ca n partly absorb or prevent the tidal function reaching the inner core, the inner core is less influenced by tidal friction. So, the inner core spinning velocit y is the fastest. In the same way, because the elastic asthenosphere below the l ithosphere can also do the same function as the outer core does, the main mantle sphere (main body of the mantle except the asthenosphere) spins faster than the lithosphere does. So, we can draw a differential rotation model of the three s pheres in the earth: rotation rate of the lithosphere <that of main mantle sphe re <that of the inner core. The model system is the largest one of layer-slip, plate's drift and magnetic field formation may be of the same background of geo dynamics.
Keywords:tidal energy  differential rotation  the earth's layer-skip model
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