Huang (1945) named the Sino-Korean block for the first time and separated it as a unified tectonic unit. The Precambrian metamorphic rocks exposed in Liaodong, Jinan and the northern part of the Korean Peninsula are linked together, which is called the Dongman Block, and is separated from the Korean Block by the Pyongyang Platform. In 1980s, Zhang Wenyou et al. (1986) regarded the whole Korean peninsula as a unified ancient block when compiling the land-sea structural map of China and its adjacent areas.
In recent years, based on the study of the Linjin system in the central part of the Korean Peninsula, the Linjin River fold belt or orogenic belt has been put forward. At present, many researchers regard it as the eastward extension of Dabie-Sulu orogenic belt, and naturally infer that the northern and southern parts of the Korean Peninsula belong to China and Yangtze Craton, forming the basement of the North Yellow Sea and the South Yellow Sea Basin respectively. On the basis of the above basic understanding, some researchers have also simulated the relationship between the Tanlu fault and the Hunan fault in southern Korea (Yin et al., 1993).
On the other hand, some researchers still insist on regarding the Korean Peninsula as a unified ancient craton block, and believe that there is a NW-trending "Yellow Sea Central Fault Zone" in the waters west of the peninsula, which makes the east and west sides of the fault not connected.
(B) the perspective of comparative analysis
On the basis of paying full attention to the basic geological facts and the latest research results, from the perspective of paleotectonic analysis and comparative tectonic analysis, the structural layers formed in different stages of tectonic movement are stripped one by one and analyzed layer by layer, and the similarities and differences of structural construction and tectonic environment of different structural units under different time and space conditions are analyzed in detail.
From the above point of view, through the comparative structure analysis of related tectonic units and their different evolution stages in eastern China and Korean Peninsula, they can be divided into three different types in similarity and difference.
1. Liaojiao block and Korea block, and Jihei orogenic belt and Tumen River orogenic belt are connected or closely related, and their occurrence, development, formation and deformation characteristics are basically the same or similar.
(1) in the division and evolution of tectonic units
As mentioned earlier, Liaojiao and North Korea have four secondary structural units with two ridges and two depressions, which can be compared one by one. The Jihei orogenic belt extends to the Tumen River orogenic belt, and their main orogeny is also consistent with the "closed" period (late Hercynian-Indosinian period).
(2) Structural characteristics of craton basement.
The Archean-Proterozoic craton basement in northern North China, especially in Liaodong and Jinan, is very similar to the northern Korean Peninsula in geological age, rock types, metamorphic deformation characteristics, occurrence and development process (Figure 3- 15).
Fig. 3- 15 Paleostructural Map of Archean-Proterozoic Craton Basement in Yanshan Mountain and Its Adjacent Areas
(According to Cui, 1980, 1995)
1-Proterozoic anticline and inversion anticline; 2- Paleoproterozoic syncline and reversal syncline; 3- Archean anticline and inversion anticline; 4- Archean syncline and reversal syncline; 5- Proterozoic schistosity and schistosity; 6- Archean foliation and foliation; 7- Phanerozoic faults and concealed faults; Palaeozoic intermediate-acid intrusive rocks in 8 yuan; 9- Archean intermediate-acid intrusive rocks; 10- greenstone belt; 1 1- carbonate formation; 12 —— molar structure after Lvliang orogeny; 13-the dividing line between Proterozoic and Archean; 14- positive magnetic anomaly; 15- negative magnetic anomaly; 16- oval structure; 17- ductile shear zone; 18- magnetic anomaly line of fault zone
(3) Early evolution of craton
After the Lvliang Movement and its equivalent Motianling Movement formed the crystalline basement of the Sino-Korean Craton, the Liaojiao and North Korea blocks experienced the Mesoproterozoic uplifting and denudation stage. On the unconformity surface of the Yan-Liao Movement, sedimentary construction sequences similar to those of the early craton evolution were produced, represented by Yongning Group-Xihe Group, Penglai Group and xiang yuan Group respectively, which are quite similar in uplift layout, paleogeography and paleostructural characteristics (Table 2-2; Figure 3- 16).
(4) Development characteristics of coal-bearing strata in Late Paleozoic.
According to the late Paleozoic Carboniferous-Permian sedimentary formation types, coal accumulation conditions and paleogeographic and paleostructural characteristics in eastern China, it can be roughly divided into three different types: Meng Xing-Hebei Black Type, North China Type and Lower Yangtze Type (Figure 3- 17). Among them, the Meng Xing-Jihei type, which reflects the active zone and is dominated by marine facies and has undergone low-intermediate metamorphism, is connected with the Tumen River belt in northern Korea; The North China type is characterized by the development of coal-bearing formations in the Middle Carboniferous-Late Permian marine-continental craton above the Middle Ordovician, and the coal-bearing formations and stratigraphic fossils in Pingnan Depression and Huichuan-Liyuan Depression at the same time have the characteristics of North China type.
Figure 3- 16 Mesoproterozoic sedimentary isoline and paleotectonic map of Yanshan and its adjacent areas
(According to Cui, 1977, 1996)
Above: 1- Yanshan Depression; 2- Jiaoliao sag; 3- Yinshan sag; 4- uplift; 5— uplift axis; 6- synsedimentary fault; 7—Pt2+3 formation thickness (m); 8- volcanic rocks; 9- granite; 10- moraine deposit ()
Below: Ⅰ1-Northwest Hebei Depression; Ⅱ1-Miyun uplift; Ⅰ 2-Northern Hebei-Western Liaoning Depression; Ⅱ 2-Shanhaiguan-Yiwulu Mountain Uplift; Ⅰ 3-Fanhe Depression; Ⅱ 3-Longgang uplift; Ⅰ 4 —— Upper Hunjiang Depression
2. The comparative structural analysis of Linjiang structural belt and Dabie-Sulu orogenic belt shows that there are great differences in structure, structure, occurrence and development characteristics between them.
As far as its material composition and deformation characteristics are concerned, the Linjin River belt has some basic conditions to be divided into Paleozoic fold belts (the paleogeography and paleostructure of Ordovician-Silurian and Devonian are obviously different from those of China-Korea craton). However, its landmark stratigraphic system, Linjin Group, is only Devonian, with a wide distribution range of 15~20km and a length exceeding 15 ~ 20k m. The degree of metamorphism is regional metamorphism dominated by low greenschist facies. Up to now, no high-pressure and ultra-high-pressure metamorphic belts have been found in Linjinhe belt. In terms of its duration (Devonian, about 57Ma), scale and metamorphic characteristics, it is not enough to become an orogenic belt continuous with the Dabie-Sulu belt. Therefore, the author thinks that the Linjiang structural belt is an intracontinental (intraplate) orogenic belt based on the continental crust of the ancient craton, and the Dabie-Sulu orogenic belt is bounded by the central fault zone of the Yellow Sea (Hou Xiang) in the northwest direction.
Fig. 3- 17 Overview of Carboniferous-Permian Paleostructure-Paleogeography in the Eastern Pacific of China.
(According to He Cui, 1999)
1 ~ 6 —— synsedimentary paleostructure (legend 5 is sedimentary isoline, unit: m); 7 ~11-stable sedimentary formation in North China; 12 ~ 17—— stable sedimentary formation in Yangtze area; 18 ~ 19- Xing 'an-Inner Mongolia, Taiwan Province province active volcano-sedimentary formation; 20 ~ 22— Transitional Volcano-Sedimentary Formation
3. The comparative structural analysis of the Gyeonggi Block-Wochuan Structural Belt-Lingnan Block in the south of Linjin River and Yangtze Craton shows that the difference is greater than the similarity, and the big difference is less than the similarity.
If the age of the Wochuan Group in the Wochuan belt is indeed late Precambrian, its lithology, formation and folding period are equivalent to those of the Yangtze Craton. But in other aspects, such as Archean-Proterozoic metamorphic rock series are widely distributed throughout the Korean peninsula and have similar characteristics; In particular, the Carboniferous-Permian structural types and coal-bearing characteristics of the whole Korean peninsula belong to North China type. The Mesozoic Indosinian and Yanshanian tectonic-magmatism is also obviously related to North China. Therefore, the author puts the main body of the Korean Peninsula within the scope of the China-Korea Craton.