The bulk composition of the continental crust can be constrained from its surface heat flow. Published values of heat flow and heat production from 17 areas ranging in age from 3.3 to 0.4 Ga are compared. In the Superior province, the ca. 2.7 Ga accreted belts have a heat flow of $41{\text{mWm}}^{-2}$, significantly higher than that in the older, ca. 3.0 Ga, craton core ($32{\text{mWm}}^{-2}$) (Jaupart et al., 2014). The mean surface heat flow values are $40\pm 1.2{\text{mWm}}^{-2}$ for the Archaean areas, and $53\pm 1.9{\text{mWm}}^{-2}$ for the post-Archaean. Heat flow values into the base of the crust are constrained from P-T estimates in lithospheric mantle xenoliths, and subtracted from the surface heat flow to calculate the bulk crustal heat production, whereupon there is a strong correlation between the surface heat flow data and the calculated average bulk crustal heat production values. Average crustal heat production values are described in terms of two component mixtures of felsic crust with $>57\text{\%}$ SiO₂, and mafic crust with $<57\text{\%}$ SiO₂, which is suggested to be more robust than relying on an average seismic model, given the complexity of the crustal structure and how it varies between provinces, and sometimes within a single province. The proportions of the mafic crustal component required to account for the regional bulk heat production values in 5 areas older than 2.8 Ga range from 60–78% consistent with a fixed mafic proportion of $\sim 70\text{\%}$. This is higher than the proportion of lower, mafic crust in the present bulk crust of Rudnick and Gao (2014), which is 43%, and the estimated bulk crust MgO values change from 10–6.6% in areas older than 2.8 Ga, to $\sim 5\text{\%}$ MgO for the younger areas. The bulk crust in the late Archaean was on average more mafic than the bulk crust at the present day, and it had a bulk crust Rb/Sr value of $0.12\pm 0.04$.

大陆地壳的整体成分可以受到其表面热流的限制。比较了年龄从 3.3 到 0.4 Ga 的 17 个区域的热流和产热公布值。在苏必利尔省，ca。2.7 Ga 增生带的热流为$41{\text{兆瓦}}^{-2}$，明显高于老年人，ca。3.0 Ga，克拉通核心（$32{\text{兆瓦}}^{-2}$）（Jaupart 等人，2014 年）。平均表面热流值为$40\pm 1.2{\text{兆瓦}}^{-2}$ 对于太古代地区，和 $53\pm 1.9{\text{兆瓦}}^{-2}$对于后太古时代。进入地壳底部的热流值受岩石圈地幔包体中的 PT 估计值的约束，并从地表热流中减去以计算地壳总产热，因此地表热流数据与计算平均值之间存在很强的相关性大块地壳产热值。平均地壳产热值是根据长英质地壳的两种成分混合物来描述的$>57\text{\%}$SiO ₂和镁铁质地壳$<57\text{\%}$考虑到地壳结构的复杂性以及它在不同省之间（有时在单个省内）的变化，SiO ₂被认为比依赖平均地震模型更稳健。在 5 个大于 2.8 Ga 的区域中，占区域大量产热值所需的基性地壳成分的比例范围为 60-78%，与固定的基性比例一致$～70\text{\%}$. 这高于 Rudnick 和 Gao (2014) 的现有大块地壳中下部基性地壳的比例为 43%，估计大块地壳 MgO 值从 10-6.6% 在大于 2.8 Ga 的区域变为$～5\text{\%}$MgO 用于较年轻的区域。太古代晚期的块状地壳平均比现在的块状地壳具有更多的基性，并且块状地壳的 Rb/Sr 值为$0.12\pm 0.04$.