The characteristics of late Quaternary strata in East China are subject to the tectonic activities and the river-laden sands. On tectonic uplift areas, river loads, mainly composed of coarse sediments, are usually small, and the first kind of late Quaternary strata are developed, characterized by slight thickness and coarse sediments, very thin marine silts, and shallow bedrock. All these factors are favorable for construction of offshore building. Developed on the tectonically continuous depression area, where river loads are large and mainly composed of fine-grained sediments, the other kind of late Quaternary strata are characterized by big thickness, several marine beds, and a striking difference of engineering mechanical properties between marine and facies of land beds, where the beds need to be softened before constructing offshore engineering structures. In terms of types and assemblages for late Quaternary sediments, the coastal areas in China could be classified as three different engineering areas, namely, Area I, II, and III. Area I is distributed from the coast of the Changjiang River to that of Liaohe River except Shandong Peninsula; Area II is made up of the coasts of Fujian, Guangdong, Guangxi Province, Liaodong, and Shandong Peninsula; Area III is made of the coasts in the vicinity of large estuaries on tectonic uplift zones, such as the coast of the Zhujiang River and the coast along Zhejiang province.
When exploring for oil and gas, laying submarine cables and pipelines in offshore areas, the properties of engineering mechanics of late Quaternary sediments as well as their distribution and vertical sequences should be known. It is of some reference value for programming engineering constructions in offshore areas of China that the type and category of late Quaternary sedimentary beds along the coasts of China are analyzed macroscopically. This paper deals with the structure, physical, and mechanical properties, genetic cause, and conditions of late Quaternary sedimentary strata in coastal areas of China as well as their characteristics of distribution.