【摘要】 中国海陆莫霍面及深部地壳结构特征研究是东亚地区宏观构造格架研究中的重点内容之一.本文以地震测深等数据为约束信息,以重力数据为基础,通过分区计算,反演了中国海陆莫霍面深度.依据地壳性质与莫霍面深度分布特征,划分了莫霍面深度梯级带与分区,并对各分区的莫霍面分布特点进行了归纳、总结.并选取阿尔泰—巴士海峡典型剖面进行了重、震反演,建立了密度结构.剖面上莫霍面深度和深部结构能够清晰地反映中国大陆"三横、两竖、两三角"构造格架中的两横和两竖,在昆仑—秦岭—大别以北的准噶尔地块和中朝地台莫霍面深度45~50km,而其以南至贺兰山—龙门山之间的祁连、柴达木至松潘—甘孜的莫霍面呈"W"型起伏,莫霍面深度由祁连地块北部的50km,加深至68km,在柴达木盆地抬升至58km,在阿尼玛卿山莫霍面降至68km,向南逐渐抬升至四川盆地的44km,经大兴安岭—太行山—武陵山这一竖的台阶式抬升至华南褶皱带的35km,在江绍—南岭以南缓慢抬升至南海北部陆架区的20~25km.在巴士海峡处南海沿马尼拉海沟向东俯冲,莫霍面形态较复杂.同时剖面上祁连—柴达木地块的中下地壳存在一个低速、低密度体,推测其可能是由于部分熔融引起的,是青藏高原东北缘壳内物质流动的通道.更多还原

【Abstract】 The study on Moho depth and crustal structure in the land and seas of China is one of the focused issues for research on macro-structural framework of East Asia.In this paper,the Moho depth in the land and seas of China and adjacent areas is calculated through sub-regional gravity data inversion with deep seismic sounding data as constraints.The Moho depths are divided on the basis of crust characters combined with the distribution of Moho depth gradient belts and characteristics of Moho depth distribution in each sub-region are summarized.The density structure of the Altay—Bashi Channel profile is established by gravity and seismic joint inversion.The Moho depth and deep structure of the profile can clearly reflect the tectonic framework of"three horizontals and two verticals,two Triangles"in China.On the north side of Kunlun—Qin Ling—Dabie horizontal,the Moho depth in the Junggar massive and Sino—Korean platform changes from 45 to 50km,while between the Kunlun—Qinling—Dabie horizontal and Helan Mountain—Longmen Mountains vertical,the Moho depth in the Qilian,Qaidam to Songpan—Ganzêshows a W-shape relief.The Moho depth in the north Qilian block is 50 km and deepens to 68 km,rises to 58 km in the Qaidam Basin,extends downward to 68 km in the A′nyêmaqên Mountains,and uplifts gradually southward.It is 44 km in the Sichuan Basin.Across the Da Hinggan Ling—Taihang Mountains—Wuling Mountain vertical stepped uplift,it is35 km in the South China fold belt.The Moho depth uplifts slowly in the south side of Jiangshao—Nanling,20~25km deep in the northern continental shelf of South China Sea.In the Bashi Channel,the Moho is complicated due to eastward subduction of the South China Sea along the Manila trench.There is a low-speed,low-density body in the middle and lower crust of the Qilian block and Qaidam block,suggesting it may be caused by partial melting,and existence of the crust material flow channel in the northeastern margin of the Tibetan Plateau.更多还原