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本文根据重力资料22条剖面的计算结果,提供了中国东南部及其毗邻海域的Moho.、Conr.界面分布和深部重力异常图(△g_D)。同时计算了不同深度压强偏差(△P)和Airy—Woollard均衡地壳厚度,分析了不同构造环境的地壳结构模型。结果表明,中国东南部及其毗邻海域在深部构造和某些地球物理特征上具明显的分区分带性,地壳厚度自西向东由陆到海逐渐变薄,显示出大陆型、过渡型、大洋型分别为M面剧变(斜坡)带所分隔的台阶式地壳结构特征;M面剧变(斜坡)带——拗陷区(系)——隆起带(区)配置的深部构造格架表现为挤压——拉张式的地壳结构体制,并与西太平洋大陆边缘海沟——岛弧——弧后盆地体系相适应。本文研究了深部构造与大地构造发展和地壳演化的关系,探讨了赣江流域——下扬子——苏北——华北平原——下辽平原中、新生代裂谷系、海陆相连的转换断层以及逐级递进式扩张的东海成因模式等理论问题。此外,还提供了一个估算地壳厚度的经验公式(H～△g_B)。
Based on the results of 22 sections of gravity data, the paper provides the Moho., Conr. Interface distribution and deep gravity anomaly map (△ g_D) in southeastern China and its adjacent waters. The pressure deviations (ΔP) and Airy-Woollard equilibrium crustal thicknesses at different depths were calculated. The crustal structure models with different tectonic settings were analyzed. The results show that the southeastern part of China and its adjacent sea areas have obvious zonation and zonation on deep structures and some geophysical features. The crustal thickness gradually decreases from land to sea from west to east, showing that the continental type, transitional type and oceanic Are the stepped crustal structural features separated by the M-plane uplift (slope) zone, respectively. The deep tectonic framework with M-plane uplift (slope) zone-depressions zone-uplift belt Pressure-tensioned crustal structure and is compatible with the trench-island arc-backarc basin system on the margin of the western Pacific Ocean. This paper studies the relationship between the deep tectonics and the tectonic evolution and crustal evolution and discusses the Mesozoic and Cenozoic rift system in the lower reaches of the Yangtze River basin from the Yangtze River to the North Jiangsu Plain to the Lower Liao Plain, As well as gradual expansion of the East China Sea cause model and other theoretical issues. In addition, an empirical formula to estimate the thickness of the earth’s crust (H ~ △ g_B) is also provided.