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在室温和等静水压下测定了大别超高压变质带榴辉岩和麻粒岩至1 GPa压力下的P波和S波速度.研究表明,超高压榴辉岩具有高密度(3.3～3.6g·cm~(-3))、高波速和弱的各向异性(1.4％～2.6％),麻粒岩呈现了低的密度(2.8～3.1g·cm~(-3))和波速、高的Poisson比(0.28～0.29),高压榴辉岩具有最强的各向异性(6.1％～8.4％).岩石波速同深地震测深剖面对比表明,大别造山带下地壳可能存在榴辉岩,但是数量应很少,而上地幔具有同超高压榴辉岩或者蛇纹石化/含水纯橄岩相似的地震波速度.推测地壳物质以榴辉岩的形式,通过拆沉作用进入地幔,少部分榴辉岩折返回地壳.
The P-wave and S-wave velocities of eclogite and granulite in the Dabie UHP metamorphic belt at 1 GPa pressure were measured at room temperature and isostatic pressure.The results show that the ultrahigh-pressure eclogite has high density (3.3 ~ 3.6g · cm -3, high wave velocity and weak anisotropy (1.4% -2.6%). The granulite has low density (2.8 ~ 3.1g · cm -3) and wave velocity , High Poisson's ratio (0.28-0.29), and high-pressure eclogite have the strongest anisotropy (6.1% -8.4%). Comparing the rock velocity with deep seismic sounding profiles shows that there may be some durons in the lower crust of the Dabie orogenic belt Hyphaloses, however, should be present in small quantities and the upper mantle has seismic velocity similar to that of UHP eclogites or serpentinite / hydrous dunites. It is hypothesized that crustal material enters the mantle through detachment in the form of eclogites, A small portion of eclogites fold back to the crust.