西南次海盆洋壳温度变化对岩石热导率的影响

发布时间：2018-07-08 16:17

  本文选题：温度 + 热导率　； 参考：《海洋地质与第四纪地质》2016年02期

【摘要】：温度对岩石热导率的影响是一个重要的地热学研究课题。在前人岩石热导率实验的基础上,结合南海西南海次盆地壳实际资料,用数值模拟的方法,对倒数型、直线型和指数型热导率-温度模型系数进行了约束,并对温度对热导率影响条件下莫霍面深度的求解方法以及海底热流与莫霍面温度关系的探讨产生了新的认识。计算结果表明:倒数型(K(T)=a+b/(T+c),a、b、c为常数)和直线型(K(T)=a·T+b,a、b为常数)热导率-温度模型系数呈线性相关,指数型(K(T)=a·ebT,a、b为常数)则更符合二次多项式形式,据此可简化热导率-温度表达式系数个数,使岩石热导率与温度之间的定量化描述更进一步。根据模拟结果与实验室统计结果对比分析得到西南次海盆莫霍面深度为14~16km。通过热导率-温度模型系数反演发现,热导率受温度影响时海底热流值同莫霍面温度呈正相关,当海底热流为100~125mW/m2、莫霍面深度为10.3km时,西南次海盆莫霍面温度为420~540℃,且随莫霍面深度增加而升高,当莫霍面深度增至14~16km时则可达600~1 000℃。
[Abstract]:The influence of temperature on the thermal conductivity of rock is an important subject of geothermal research. On the basis of previous rock thermal conductivity experiments and combined with the actual data of the southwest sea basin in the South China Sea, the coefficients of reciprocal, linear and exponential thermal conductivity-temperature models are restricted by numerical simulation. A new understanding of the solution of Moho surface depth under the influence of temperature on thermal conductivity and the relationship between submarine heat flux and Moho surface temperature is also given. The results show that the reciprocal type (K (T) a b / (T c) is a constant) and the linear type (K (T) a T BBA B are constant) the coefficient of the temperature model is linearly correlated, and the exponential type (K (T) a ebTab is a constant) is more in accordance with the quadratic polynomial form. Based on this, the number of thermal conductivity-temperature expression coefficients can be simplified, and the quantitative description between thermal conductivity and temperature of rock can be further improved. According to the comparison and analysis between the simulation results and the statistical results of the laboratory, the depth of the Moho surface of the southwest subbasin is 14 ~ 16km. From the inversion of the coefficient of thermal conductivity-temperature model, it is found that the submarine heat flux is positively correlated with the Moho surface temperature when the thermal conductivity is affected by temperature. When the undersea heat flux is 100 ~ 125mW / m ~ (2) and the Moho depth is 10.3km, the Moho surface temperature of the southwest subbasin is 420 ~ 540 鈩，

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