【摘要】 根据准动力学计算方案，通过采用等效热源和等效热传导系数的方法，用有限元法计算了不同俯冲角度，而俯冲速度为８ｃｍ／ａ、年龄为１００Ｍａ的俯冲带在稳定俯冲状态的热结构．计算结果表明俯冲带在接近６７０ｋｍ间断面的最低温度可达到１１００℃．全地幔对流模式热结构的计算结果表明６７０ｋｍ间断面以下可存在最低温度达１０００℃的低温区，相应于有０．７％—３．０％的Ｐ波低速异常存在．双层地幔对流模式表明，在６７０ｋｍ间断面以上可有与周围地幔相差约４００℃的水平舌状低温区存在，相应于０．５％—１．４％的Ｐ波低速异常．更多还原

【Abstract】 According to the quasi-dynamic scheme,the thermal structures at stable statefor different dip angle of the subducting slabs,in which the subducting velocityand the cooling time are 8 cm/a and 100Ma respectively,were calculated by FEM.Above the 670km discontinuity the minimum temperature near the 670km discontinuityin the subducting slab is about 1100℃; Below the 670km discontinuity there is alow temperature zone for whole mantle convection model,the lowest temperature inthe center is about 1000℃,which is 400℃lower than the one of surroundingmantle;The thermal structures of the subduction zone for the two layered mantleconvection model were showed,there being a tongue shaped horizontal low temperaturezone above the 670km discontinuity,the temperature of which is 400℃ lower thanthe surrounding mantle.更多还原