地幔热力不稳定性分析  

ANALYSIS OF THE THERMODYNAMIC UNSTABILITY IN THE MANTLE

作　　者：李志安[1] 钟建华[2] 

机构地区：[1]中国科学院长沙大地构造研究所,长沙410013 [2]华东石油大学,东营257062

出　　处：《大地构造与成矿学》1998年第4期353-360,共8页Geotectonica et Metallogenia

基　　金：国家自然科学基金

摘　　要：根据地幔热动力学模型，分析了地幔在多种因素（特别是地球自转效应）影响下的热力不稳定性条件和临界条件，结果表明，地质年代在影响地幔热力不稳定性的诸因素中，地幔内部的热源（放射性生热、相变生热、绝热压缩生热和底部加热）效应能够使地幔lavleish数增大，即增大地幔运动的动力；而地球的自转效应却能减小地幔运动的临界阻力，因此它们对地幔热力不稳定性都具激发作用，而对地幔粘滞性和热传导效应，关系式表明，它们对地幔热力不稳定性都具致稳作用。对于岩石图绝对运动的影响，取决于岩石圈绝对运动方向与地幔所受合力方向的相互关系。Based on the thermodynamic models of the mantle, the thermodynamic unstability conditions and critical conditions of the mantle under the influence of numerous factors are analysed. Results show, among the factors influencing the mantle's motion, thermal effect in the mantle such as radiogenic heat, factes-change heat and adiabatic heat may increase the force driving the mantle, whereas rotation effect of the earth may decrease the critical resistance.Both effects therefore can excite the motion of the mantle. Moreover, the formula reveals that both the viscosity of the mantle and heat conduction may stabilize the motion of the mantle. As for the lithosphere, the influence of the absolute motion of the lithosphere on the mantle's motion depends on interrelation between the direction of absolute motion of the lithosphere and the direction of composite forces in the mantle.

关 键 词：地球自转 热力不稳定性 地幔 岩石圈 

分 类 号：P183.2[天文地球—天文学] P312