After many scholars' research (such as Wang Hongzhen,1986; Guo Lingzhi,1979; Luo Zhili,1979; Yang, Yang et al.,1985; Yuan Xuecheng et al.,1986; Xie Douke et al., 1996), the landscape of the Yangtze River landmass is gradually becoming clear. The unified Yangtze landmass was formed in Jinning movement (about 800Ma), and the landform of early Sinian is still complex, including conglomerate, moraine, sandstone and volcanic rocks. In the Late Sinian after leveling, shallow platform sediments were the main sediments, surrounded by deep-water oceans, with little foreign debris, and entered the stage of free land mass. The age of the Yangtze unified landmass is less than half that of the North China landmass. In the complicated assembling process of Yangtze plate, a large number of oil fields may have formed in Mesoproterozoic in North China block. However, the passive continental margin of the Yangtze block has a good extensional environment, especially on the south side, which is very conducive to oil and gas generation, migration and trap accumulation.
The Yangtze landmass is spliced by several older landmasses, such as central Sichuan, central Hubei, northern Jiangsu and southern Yellow Sea, and still has its own characteristics after splicing. Zhou Kun [265] thinks that they have similar metamorphic age and magnetic anomaly characteristics, and have close structural relationship with each other. They should belong to the same Proterozoic or older block, but they are discrete micro-blocks formed after Proterozoic extension and cracking. The article [26 1] co-authored with Li pointed out that during the Jinning Movement, the Central Sichuan Uplift and the Jiangnan Uplift were two island arcs where the B-type oceanic crust subducted, and the Banxi Group was a back-arc inter-arc basin evolved from a trench, an arc and a basin. It is the basis of crustal eastward proliferation, and has a new trend from west to east [66]. From Archean to Neoproterozoic, it gradually grew, forming a unified hard basement of the Yangtze plate, and later became the core of the stability of South China continent.
Outside the deep-water basin (Cathaysian Ocean) on the south side of the Yangtze landmass, there are a lot of data about the ancient landmass in South China. Wang Hongzhen [84] clearly pointed out that South China is "two platform areas": Yangtze is a consolidated platform formed before Sinian and belongs to a stable continental crust area; Another pre-Sinian stable continental crust area is the Indo-China Peninsula platform (Huang et al., 1977), which has been partially fractured and subsided. Xie Douke et al. [66] put forward that South China United continent can be roughly divided into Yangtze block basement and Wuyishan basement according to the crustal growth process and mantle plume structure characteristics of South China continent. In recent years, many ancient rocks over 2000Ma have been found in the amphibolite facies thermal metamorphic belt in Wuyishan area. South China continent not only shows that the two continents have different ages, but also shows that the two continents have different tectonic rock properties. The basement of the Yangtze block is mainly a "double-layered rock structure", the lower crust is Comati greenstone belt, and the upper crust is granite greenstone belt. Wuyi block, on the other hand, shows a "one-layer rock structure", mainly granulite amphibolite. Their structures are completely different, which is reflected in the sediment sources and characteristics of the early landmasses, and there are also essential differences.
As the core of continental stability in southern China, the Yangtze block developed a good passive continental margin in its free extension stage, which is very beneficial to oil and gas generation. It was not until the Indosinian period that there were more than 200 million years of dynamic and static tectonic activities, and the peak of oil and gas accumulation appeared in the geological history of China.