中国东部下地壳是中性的吗？

We start our research based on the seismic wave velocity of the crust beneath the main tectonic units of the eastern China summarized by Li et al. and Gao et al. to study the lower crustal composition. The predictions of the lower crustal composition are through two aspects. On the one hand, by comparing the observed velocities of the eastern lower crust with the observed velocities of the various rocks from Christensen and Mooney. On the other hand, the crustal densities of the main tectonic units are computed using an empirical velocity to density conversion: ρ = a + bVp proposed by Hasterok and Chapman. To determine the uncertainties in the crustal densities, we perform a Monte Carlo analysis perturbing the density structure to compute the density correction. The result shows that the seismic wave velocity of the lower crust of the main tectonic units in eastern China are corresponded with the velocities of the mafic rocks. And also most of the densities of the lower crust are greater than 3000 kg/m3, which constrained the rocks belonging to the lower crust are mafic rocks. Therefore, the lower crust of the eastern China is suggested to be mafic in composition.