【摘要】 本文全面收集整理并解析了地学断面、地震测深、体波和面波层析成像资料,得到了苏鲁大别造山带及其邻区岩石圈1°×1°三维P波速度数据体。研究结果表明,苏鲁与大别造山带高压、超高压变质带的岩石圈速度结构具有上地壳明显高速且上凸;中地壳增厚;下地壳埋藏较深且下凹等相似的基本特征。苏鲁和大别超高压变质带下的莫霍面比其周围深2～4 km,深度分别达到32～33 km和34～38 km。在大别造山带,有地壳低速体从南向北俯冲到上地幔的迹象,可能显示了扬子地块地壳物质向华北地块俯冲,坠入上地幔的残留体。超高压变质带岩石圈底部的地幔,往往有明显高速层或高速体存在。苏鲁与大别地区的岩石圈速度结构不同特征及其成因在于苏鲁地区上地壳P波速度更高,但是,下地壳下凹没有大别地区明显,而且区域构造较为均一。这可能是受到郯庐断层左行平移的主控影响所致。郯庐断裂带的上、中地壳和上地幔表现为相对低速异常,郯庐断裂及其地下延伸部分将岩石圈地幔浅部低速层和深部高速层切为两段,其影响深达岩石圈底部约90 km处。更多还原

【Abstract】 A 3-D lithospheric structure of P-wave velocity in the Sulu -Dabie orogen area has been studied based on the results from the Global Geological Transect projects (GGT), wide-angle seismic sounding, teleseismic tomography and other data. The obtained results are shown in plates with the data density of 1°×1°. The lithospheric structures in the ultra-high pressure metamorphic (UHPM) belts in the Sulu and Dabie areas show similar characteristics more or less. Higher P-wave velocity exists in the upper crust and forms a convex high-velocity region. The thicken middle crust is characterized by normal or lower P-wave velocity. The Moho discontinuity is depressed under the UHPM terranes. The Moho discontinuity in the Sulu and Dabie orogen areas are deeper than their surroundings and the depths reach 32~33 km and 34~38 km, respectively. The P-wave velocity of the upper crust in the Sulu UHPM belt is higher than that in the Dabie area. The depressing of the Moho discontinuity beneath the Dabie, however, is obviously deeper than that beneath the Sulu region. It is attributable to the effect of the left-lateral strike-slip movement along the Tanlu fault in the Sulu area.更多还原