地球初期壳幔演化的物理过程

Physical Process of Mantle-Crust Evolution in the Early Stage of the Earth

原始地幔处于全球性的高温熔融状态,其上层的冷却演化过程可大致分为3个阶段:高熔点矿物结晶沉降阶段、岩浆不混溶阶段和固化成壳阶段。在此过程中,原始地幔逸出挥发性物质,形成了地球的超临界流体圈。通过岩浆不混溶作用所形成的富Si-Al质岩浆最终固化为原始大陆壳。超临界流体圈的分解,分别形成酸性H2O圈和CO2大气圈。

The primitive mantle of the earth was in a high temperature global melt state. The cooling-evolution process of the upper layer of the primitive mantle could be divided into 3 phases： （1） a phase of crystallizationaccumulation of minerals with high melting temperatures, （2） a phase of silicate liquid immiscibility and （3） a phase of melt solidification. During the process of the cooling-evolution ,volatile components were released from the primitive mantle to have formed the supercritical fluid sphere later. The magma rich in Si-Al, which were formed by silicate liquid immiscibility, were solidified to form the primary crust. The supercritical fluid sphere was then decomposed to have formed acidic hydrosphereand CO2 aerosphere respectively.