(1) Longmenshan-Yulong Snow Mountain Uplift Zone
The belt extends to the northeast, reaches Hanzhong in the northeast, intersects with Qilian-Dabie belt in the northwest, obliquely joins with Qinling belt, passes through Kangding in the southwest, reversely joins and recombines with Danba anticlinorium and Sichuan-Yunnan meridian belt in the northwest, passes through Sichuan-Yunnan meridian belt, passes through Jinping Mountain and Yulong Snow Mountain, and extends to the east of Diancang Mountain in the southwest, and reversely joins and recombines with Ailao Mountain structural belt in the northwest. It spans the middle of the Yangtze-Tarim block and is divided into two parts by the Sichuan-Yunnan meridian belt. The northeast section is called Longmenshan fault fold belt, and the southwest section is called Yanyuan-Lijiang fault fold belt, which is characterized by extensive development of nappe structures.
Fig. 2.28 Schematic diagram of Sinian S-type basin in southern Liaoning-Xuhuai (modified according to Li Zikun 1985).
① Longmenshan fault fold belt: it starts from Mianxian county in southern Shaanxi in the north, passes through Guangyuan-Mao Wen, guanxian-Baoxing and Tianquan, and obliquely crosses the Sichuan-Yunnan meridian belt to the far side of Luding, with a length of 500km and a width of only 25-40 km. It consists of NE-trending folds, compressional fractures and compressional zones, and generally extends 40 ~ 50 from north to east. The main structural features of this structural belt are four anticlinorium, three synclines and four large strike-compression and torsional-compression fault zones. These four anticlines are called sedan chair top-wooden support anticline, Guan Peng-Jiuligang anticline, Baoxing anticline and Tianjingshan anticline. The first three cores are exposed in the pre-Sinian and Jinning-Chengjiang intermediate-acid magmatic rocks, and the two wings are composed of Sinian-Triassic, which are polygonal and oblique, which is caused by the anticlockwise torsion of the main structural belt. The three synclines are Wu 'an syncline, Yanjing-Wulong syncline and Tangwangzhai-Yangtianwo syncline, and the strata involved are Sinian-Triassic, during which no angular unconformity is found. The axis of a single fold is 45 ~ 60 to the east, and both ends are S-shaped, 45 to the east of the echelon axis. These four major faults are Qingchuan fault zone, Mao Wen fault zone, Beichuan-Yingxiu fault zone and Jiangyou-guanxian fault zone, which strike 45 ~ 60 to the north and extend for about 200 ~ 400 kilometers. The first three faults cut Triassic and previous strata and rock masses, while the last fault cuts Jurassic, and its sections all tend to the northwest, with an inclination angle of 50 ~ 80. The southern section of Beichuan-Yingxiu fault has a dip angle of only 20, and the section is wavy. Oblique scratches are often covered by horizontal scratches, and fault tectonic rocks are developed. The fault zone is imbricate in profile. According to their deformation characteristics and cutting stratigraphic relationship, these faults were mainly formed in Indosinian and Yanshan periods, and in Himalayan period, they were characterized by thrust nappe and clockwise horizontal dislocation (Figure 2.29). They are related to the eastward thrust of the Qinghai-Tibet Plateau and the activities of near-earth objects in the meridian zone.
② Yanyuan-Lijiang fault-fold belt: it obliquely crosses between Sichuan-Yunnan meridian belt and Sanjiang meridian belt, and was once called the depression on the western margin of Yangtze block. Generally sandwiched between the northeast Jinhe-Qinghe fault zone and Xiaojinhe fault zone, it has been in a slow subsidence zone for a long time since Paleozoic. The caprock is developed, with the maximum thickness of 16500m, especially in Devonian and Carboniferous, and the bedrock in the belt is developed. According to the deformation characteristics, it can be divided into two secondary units: Jinhe-Yongsheng fold bundle and Yanyuan-Heqing 'ao fold bundle. According to the analysis of regional tectonic data, the Yanyuan-Lijiang fault fold belt was mainly uplifted by Indosinian movement, and Caledonian movement also had an important influence on this area, which made both ends of Silurian system missing, and the Devonian system and Sinian Dengying Group in some areas were parallel and unconformity.
③ Longmenshan-Yulong Snow Mountain Fault Zone: This is the Longmen-Yulong Deep Fault Zone delineated by Ren Jishun. Generally speaking, it runs in the northeast direction, obliquely passing through Sichuan and Yunnan provinces, reaching Hanzhong area at the northeast end and Ailaoshan fault zone at the southwest end. At present, it is not consistent whether its later activities surpass Ailao Mountain and reach southwest Yunnan.
Fig. 2.29 Structural Profile of Tiantai Mountain-Bailuding Feilaifeng in Pengxian County (according to the regional geology of Sichuan Province, 199 1)
Fig. 2.30 Profile of Yanyuan nappe structure (according to the regional geology of Sichuan Province, 199 1)
The main components of this fault are Xiaojinhe fault, Beichuan-Yingxiu fault and Mao Wen fault in the northeast, Xiaojinhe-Sanjiangkou fault, Jinmian-Lijiang fault and Qinghe fault in the southwest, which are generally deep faults. The general trend is the northeast. From Paleozoic to Triassic, the sedimentary environment gradually deepened from south to north and the sedimentary thickness gradually increased. The Qinghe-Jinhe fault in the southwest section was active strongly in Neoproterozoic. In the late Variscan period, there were strong activities along several faults, including the eruption and intrusion of basic magma in Qinghe fault, Xiaojinhe-Sanjiangkou fault and Jinmian-Lijiang fault. These characteristics indicate that this group of faults had obvious tensile activity during Paleozoic-Triassic. This fault system passes through Yanyuan area to the northeast, and gradually turns to the north on the west side of the Sichuan-Yunnan meridian belt, showing a NNE direction, and gradually merges with the Yalong River fault zone of the meridian structure system and reconnects, with thrust nappe structure and Feilai peak developed along this belt (Figure 2.30).
Longmenshan section in northwest Sichuan mainly includes Mao Wen deep fault, Beichuan-Yingxiu deep fault and Jiangyou-guanxian fault. Beichuan-Yingxiu deep fault zone is the main central fault of Longmen Mountain, which was called by predecessors. It extends to the northeast and is more than 400 kilometers long. On the plane of the fault zone, it is multi-branched, and its profile is wavy, with superimposed nappe rocks in between. The basic characteristics of Longmenshan fault zone are as follows: ductile shear deformation occurs in the overlying rock sheet at the back of nappe compression zone, ductile deformation in the middle is mainly accompanied by brittle deformation, and the lower rock sheet at the front is brittle deformation; According to the deformation characteristics, the rear part is dynamic metamorphism, with medium-pressure dynamic thermal gradient metamorphic zone and migmatization, and new stress minerals or metamorphic minerals only appear in cleavage and schistosity along the shear zone in the middle part, and there is basically no metamorphism in the front rock slice; From the kinematic characteristics, dragging the axial plane of flexible shear fold, sliding shear scratches, gravel tensile lineation and mineral rotation orientation accompanied by shear slip all indicate the thrust movement of nappe from northwest to southeast. From the nappe time, from west to east, from the end of Indosinian to Himalayan period, the process of tectonic stress squeezing, migration and napping to the southeast is shown in multiple stages and stages.
The most remarkable structural feature of Longmenshan-Yulong Snow Mountain structural belt is that nappe structures or nappes are widely developed along the structural belt. Its main part is basically composed of many nappes and Feilai peaks, especially in Longmenshan area, which can be said to be a nappe mountain range accumulated by nappes. According to aeromagnetic data, the structural belt is in a regional NE-trending negative anomaly zone, in which the local ascending linear anomaly and the continuous negative anomaly gradient zone show the location of the main fault zone. There is basically no strong magnetic anomaly in the anomaly zone, and even the magnetic anomaly on exposed magmatic rocks is only 90nT, and it is an isolated anomaly in its own trap, indicating that the extension range of magnets is limited. The gravity and magnetic profiles passing through Guanpeng complex prove that the complex is a floating rootless complex with almost no extension. The fold deformation and metamorphism of this belt mainly occurred during the Indosinian movement. On the basis of the compressive deformation and thrust of Indosinian movement, the main faults became thrust nappes, which developed in Yanshan period and located in Himalayan period, forming nappe structures and Feilai peaks of different scales. There are not only Jurassic and Cretaceous molasses formations in the front of Longmenshan-Yulong Snow Mountain structural belt, but also Paleogene-Neogene and Quaternary molasses formations, indicating this nappe belt. The thrust belt of nappe structure is mostly plow-shaped, inclined to the northwest, and the surface dip angle is generally 50 ~ 60, and it tends to become very slow downward, only 5 ~10. According to petroleum seismic data, Longmenshan area has a low velocity layer about 2 1km below the surface, which is an ideal main sliding surface. As for the displacement distance of nappe, according to the present position of Feilaifeng and the position of root zone similar to its lithology and age, the maximum displacement distance is calculated to be 30~40km. Because the compressional nappe occurred in the shallow crust without deep tectonic background, there was no corresponding magmatic activity and hypermetamorphism. However, there are progressive dynamic thermal metamorphism, migmatization and stress minerals in the back and middle of the main fault zone. Qingchuan fault consists of glaucophane high-pressure metamorphic rocks and granite vein groups distributed along schists, with an isotopic age of 223Ma, which is also the product of tectonic dynamic metamorphism.
(2) Tianmu Mountain-Jiuling Mountain-Xuefeng Mountain Uplift Zone
This belt is the main part of Cathaysian tectonic system in South China, including Jiangnan uplift and its lateral fold-fault zone. The northeast structure dominated by Paleozoic folds (including some Neoproterozoic folds) is well preserved, forming a continuous anti-S-shaped Cathaysian structural belt. The core of the uplift zone is pre-Sinian shallow metamorphic rocks, and its broad wing is composed of early Paleozoic and middle Triassic strata, which is concealed eastward under the southern Jiangsu plain and continues to extend under the Yellow Sea and the East China Sea. The NE-trending Suzhou buried fault zone is an important part of it. The belt extends from central Guizhou to the south and west. Cathaysian structures in the uplift zone include both late Cathaysian structures fixed in Indosinian period and early Cathaysian structures composed of lower Paleozoic, which are consistent in axial direction and similar in deformation, but different in strength and constrained by Caledonian movement. In addition, the ancient NE-trending structural belt composed of Mesoproterozoic and Neoproterozoic was merged. Their directions are similar, and the activities they inherited are obvious. In the early Paleozoic, the uplift belt was the dividing line between the active sedimentary area in the southeast coast (trough area) and the stable sedimentary area in the west (platform area), and in the early late Paleozoic, it was the northwest dividing line of the southeast "Cathaysian ancient land". Due to the serious interference of other tectonic systems in the later period, its orientation was deflected, and its shape was strange. The north and south wings were extremely uncoordinated, even blocked and incoherent, forming the NE-NE-NE anti-S-shaped structure. The main components are as follows.
① Tianmushan-Huaiyushan Uplift Zone: It is the northeast section of Tianmushan-Jiulingshan-Xuefeng Uplift Zone, located in Huaiyushan and Tianmushan areas adjacent to Jiangsu, Anhui and Jiangxi. It consists of Tianmushan-Huaiyushan composite uplift belt, a series of fault zones and some granites, including Anji-Qimen-Jingdezhen anticlinorium belt, south and north Hangzhou-Hua Kai syncline belt and Xuancheng-East syncline belt. Anji-Qimen-Jingdezhen anticlinorium belt is in the northeast direction, and its axis is located in Qimen-Jingdezhen area. It is composed of Banxi Group, Shuangqiaoshan Group and Sinian System of Mesoproterozoic, and its two wings are Lower Paleozoic and Lower and Middle Triassic. The anticlinorium Belt of Tianmu Mountain, composed of Paleozoic, is its eastward extension, and then disappears eastward under the Jiangsu Plain. Xuancheng-Dongzhi syncline belt includes a series of open folds such as Pailou syncline, Qidu anticlinorium and Taipingping syncline. , the axial direction is 40 ~ 60 east, mainly composed of Paleozoic. The axis of anticline is Precambrian or Cambrian, and the core of syncline is Silurian, Permian and Triassic. Hangzhou-Hua Kai syncline zone consists of Hangzhou-Hua Kai syncline 50 in the north, Linpu-Shou Chang and Lanxi-Jiangshan synclines in the south and Wu Kang-Lucun and Changxing-Xiaofeng synclines in the north. It consists of early and late Cathaysian structural relics of Lower Paleozoic, Upper Paleozoic, Middle and Lower Triassic respectively.
The associated regional faults in the uplift zone are also well developed, mainly including "deep" faults such as Jiangnan, Anhui, Zhejiang and Jiangxi, northeastern Jiangxi and Jiangshan-Shaoxing, which mainly tend to the southeast and have obvious characteristics of multi-stage activity, nappe and sliding. Take Jiangnan and Jiangshan-Shaoxing fault zones as examples to briefly introduce them.
-Jiangnan Great Fault Zone: it obliquely passes through the mountainous area in southern Anhui, passes through Xuancheng from east to west, connects with Xiushui-De 'an deep fault in Jiangxi, extends to Liyang area in Jiangsu in the north, cuts Indosinian intrusive rocks, and is an aeromagnetic anomaly gradient zone along the fault zone. It formed the eastern shelf, obviously controlled the lithofacies, thickness and biota of Paleozoic, and was fixed in Indosinian period.
-Jiangshan-Shaoxing "deep" fault zone: This zone is huge, with a length of 280km and a width of about 10km, slightly S-shaped, and aeromagnetism shows an abnormal zone with a width of several kilometers. There are many stages of deformation and metamorphism along the fault zone, and the magmatic activity is strong, but the activity from Paleozoic to early Mesozoic can be attributed to Cathaysian tectonic system. Shuangqiaoshan Group in the northwest and Chencai Chen in the southeast of the fault zone have strong ductile deformation and developed thrust faults, forming imbricate thrust belts, mixed quartz diorite belts with a width of 65,438+00 km, flaky mixed plagiogranite belts and phyllite belts, and producing a large number of lenticular ultrabasic rocks. This fault is considered to be the product of the collision between Jiangnan and Cathaysian ancient landmasses in Jinning and Caledonian. It is worth pointing out that the NE-trending compressional structure in the pre-Sinian metamorphic basement covered by the unconformity of Tang Zhi Formation is different from the Paleo-NE structural belt in the early and late Cathaysian period.
② Mufushan-Jiulingshan uplift belt: it is the middle section of Tianmushan-Jiulingshan-Xuefengshan uplift belt, with Mufushan anticlinorium belt and Jiulingshan anticlinorium belt as the main parts, Pingxiang-Leping syncline belt and Hukou-Tongshan syncline belt in the south and north respectively. The axis of anticlinorium is composed of Mesoproterozoic shallow metamorphic rock series and granitic complex, and its wings are Paleozoic and Lower Triassic. The axis of syncline is mainly lower Triassic, and its wings are Paleozoic. Anticlinorium belt of Mufu Mountain is NE-NE, and slightly bends to the northwest. To the south is the anticlinorium Belt of Wugong Mountain.
On the edge of Mufushan-Jiulingshan uplift belt, the syndromic fault zones are well developed, represented by Xiushui-De 'an, Yifeng-Nanchang and Pingxiang-Guangfeng fault zones. Their multi-phase activities are obvious, and some of them have strong nappe and sliding characteristics. Xiushui-De 'an fault zone is located in the northern margin of Jiuling Uplift, with developed structural melange blocks and obvious ductile deformation, which controls the distribution of Paleozoic sediments and Yanshanian granite belts. Yifeng-Nanchang fault zone is located in the southern margin of Jiuling uplift, with a dip angle of more than 60. It consists of a series of imbricate thrust faults with obvious brittle-ductile deformation, which controls the distribution of Mesoproterozoic volcanic rocks and Mesozoic-Cenozoic basic-ultrabasic rock complex belts. Yifeng-Nanchang fault and its south Gaoqibaoshan-Gaoanxinjie thrust fault thrust southward during Indosinian-Yanshan period, and * * isomorphically formed a double-belt thrust fan or double thrust structure (Figure 2.3 1), forming a thrust nappe structure on the southern margin of Jiuling Mountain (Zhu Zhicheng et al., 1987). Pingxiang-Guangfeng fault is located in the northern margin of Wugongshan Uplift, which is the boundary fault between Yangtze Block and South China Fold System, and corresponds to the deep structural variation zone. Besides the occurrence of basic ultrabasic rocks, it obviously controls the sedimentary thickness of Neoproterozoic and Lower Paleozoic.
Figure 2.3 1 Yifeng Aoqiao-Shanggao Qibaoshan Structural Profile
③ Xuefeng Mountain-Leigongshan Uplift Belt: it belongs to the southwest section of Tianmushan-Jiulingshan-Xuefeng Mountain Uplift Belt, and is dominated by large-scale uplift belts, which are developed along the same fault zone and separated by Ma Yuan Basin. The northeast section is combined with the regional east-west structural belt to form a huge "Xuefeng arc structural belt" protruding to the northwest. It can also be divided into early and late stages: the early Cathaysian system is composed of Mesoproterozoic, Neoproterozoic and Lower Paleozoic, with clear traces; The late Cathaysian system was developed in the early Cathaysian depression zone, which consists of the Upper Paleozoic and the Lower and Middle Triassic. Due to the interference and destruction of Middle Cathaysian and New Cathaysian, its shape is very incomplete. From northeast to southwest, there are four tertiary structural belts: Wuling Mountain Fold Belt, Anhua-Taojiang Fold Belt, Qiandongnan Fold Belt and Xuefeng Mountain Fold Belt.
Qiu Yuanxi and others studied the layer slip in Jiangnan-Xuefeng area, and found and determined Caledonian fold nappe structure in the adjacent area of Hunan, Guangxi and Guizhou at the end of Xuefeng uplift. The structural styles are mainly recumbent folds and overthrust imbricate structural fans. Banxi Group is the main body, including the upper wing of a giant recumbent fold composed of Sinian, Cambrian and Ordovician, which is about 300km wide and covered by the unconformity of Upper Paleozoic. The front belt is located between Dushan-Shibing and Kaili-Guiding-Zhenyuan, and a series of imbricate overthrust structural belts are developed in the southeast. For example, along the line from Shidongkou in Zhenyuan to Liangtu Depression in Xincheng, there are five or six NE-trending reverse faults inclined to the southeast, which constitute imbricate structural fans advancing westward. Among them, Shidongkou fault shows that Banxi Group overthrusts on Cambrian, and Feilai peak and structural window structures are developed. Qiu Yuanxi and others believe that it is a continental margin folded mountain system and fold nappe structure formed by collision and extrusion of the southeast margin of Yangtze block in Caledonian. It goes without saying that bedding slip in this period is mainly the product of early Cathaysian tectonic stress field.
(3) Fujian-Guangdong Gan Long fold belt (Wuyi-Yunkailong fold belt).
It is distributed in western Fujian, eastern Jiangxi, western Guangdong, southeastern Guangxi, etc., and is mainly composed of the composite anticline belt with the pre-Sinian system, metamorphic rocks and migmatites in the Lower Paleozoic, and the composite syncline belt and fault zone with this as the core in the Upper Paleozoic. Due to the complex transformation of Nanling banded structural belt and the strong interference of central Cathaysian and Neocathaysian structures, it is discontinuous and inverted S-shaped, forming another large uplift belt parallel to the Huai Yu-Jiuling-Xuefeng giant uplift belt. Xi Yong 'an-Meixian area in eastern Guangdong is a Hercynian-Indosinian depression belt superimposed on Caledonian uplift belt, commonly known as "Yongmei Depression". The main body is northeast. In the Late Paleozoic, a single continental clastic formation assemblage with a thickness of 4500 meters was deposited, including coal-bearing formation and carbonate formation. The Upper Paleozoic consists of transitional folds and Yongmei thermodynamic metamorphic belt.
◎ Yunkailong Fold Belt: It is the southwest section of the Fujian-Guangdong-Jiangxi Fold Belt, located in Yunkaishan-Liuwandashan area in western Guangdong and southeastern Guangxi. Its main body is the anticlinorium belt composed of Sinian metamorphic rocks and migmatites in the early Paleozoic, and its side is also developed with NE-trending upper Paleozoic folds and some deep fault zones, including Dayunshan anticlinorium belt and Liuwandashan anticlinorium belt in the east and west, as well as the lower Paleozoic syncline belt in its side. The anticlinorium belt of Dayun Mountain, commonly known as "Yunkaitai Uplift", and its lateral deep faults obviously controlled the Paleozoic sedimentation. Pre-Sinian and Lower Paleozoic are mainly active flysch deposits, with a thickness of about 10000m, which gradually rose in the late Caledonian, resulting in strong regional metamorphism, migmatization and magmatism. The anticlinorium zone of Liuwandashan constitutes the central uplift zone of Qinzhou Hercynian trough (Liuwandashan uplift), which controls the distribution of the Indosinian granite zone of Liuwandashan. In Qinzhou-Lingshan area and Bobai-Cenxi area on both sides, Silurian-Early Permian flysch strata with a thickness of 10000 m were deposited, forming two NE-trending depression zones. There are some NE synclines at the edge of Yunkai uplift, mainly Yangchun Bay (Figure 2.32), Gaoyao-Qingyuan and Huaxian synclines. They are composed of Upper Paleozoic and part of Cathaysian structure in Yunkai area.
Fig. 2.32 Schematic diagram of Yangchun Bay Syncline (according to the regional geology of Guangdong Province, 1988)
In addition, on the side of Yunkai Uplift and Shiwandashan Uplift, deep faults in the northeast are well developed, such as Wuchuan-Sihui, Cenxi-Bobai, Lingshan-Qinzhou and other deep faults. Their multi-stage activities are obvious, and they are characterized by ductile deformation, thermodynamic metamorphism and multi-stage detachment. It not only obviously controlled the Paleozoic, Caledonian and Indosinian granites, but also controlled the formation and development of Jurassic and Cretaceous basins. However, their activities in the early and late Paleozoic should be the manifestation of Cathaysian structures, and they have been incorporated into the eastern wing of the front arc of South China gables since Mesozoic.
Qiongzhonglong fold belt running through the central part of Hainan Island may be an extension of Yunkailong fold belt. The main body is the anticlinorium belt in northeastern Qionghai, which is mainly composed of Proterozoic and Early Paleozoic metamorphic rocks, and its axis is located in Anding, Qiongzhong and Ledong areas. Because it is occupied by Caledonian-Variscan Qiongzhong mixed granite and Yanshanian granite, the fold preservation is extremely incomplete. The NE-trending Nankunyuan syncline and Danxian syncline are its representatives.
Among the two first-order depression zones between the three first-order uplift zones of Cathaysian structural system in South China, Cathaysian structure is also more developed than Cathaysian structural system in Paleozoic depression zones in Sichuan and Guizhou, and is mostly used by Middle Cathaysian and Neocathaysian. However, Huayingshan and Qiyaoshan NE-trending fault zones are the main structures of Cathaysian tectonic system in this depression zone, which played an important role in the establishment of Paleozoic NE-trending Sichuan Basin. Early and late Cathaysian structures can be found in the late Paleozoic depression and the Hunan-Guangxi-Guangdong-Jiangxi fold belt in southern Hunan-northeastern Guangxi and northwestern Guangxi. For example, a closed NE fold composed of Cambrian shallow metamorphic rocks can be seen in Xiaoshui Basin, which is unconformity by Devonian. Wide and gentle folds composed of Upper Paleozoic are also well developed, accompanied by faults. The upper and lower parts of Caledonian movement plane are two types of ne-trending folds and associated faults, which should be components of early and late Cathaysian structures respectively.
To sum up, the Cathaysian tectonic system in eastern China has the following basic characteristics:
1) Cathaysian system is characterized by plastic deformation, which often forms large-scale complex fold belts and depression belts with northeast strike, accompanied by large-scale compression and compression-torsion fault belts. Large faults are mostly inherited, resulting in intermediate-acid intrusive rock zones and dynamic metamorphic zones.
2) Cathaysian system was mainly formed in Indosinian movement, which can be divided into early and late stages in Jiangnan-Xuefeng uplift belt and its southeast area in South China. In the early stage, the NE uplift belt and depression belt formed in the late Caledonian period were mainly found in Wuyishan-Yunkailong fold belt, accompanied by granite belt and dynamic metamorphic belt. The late stage was formed by Indosinian movement, and the upper and lower Paleozoic in South China were angular unconformity. The tectonic lines of the two folds are basically the same, but in the Yangtze region, North China and the eastern part of Northeast China, Caledonian movement is mainly uplift, without obvious deformation, metamorphism and magmatic intrusion. Indosinian movement formed a wide range of NE uplift and depression zones in eastern China, and the deformation and metamorphism were generally consistent. Due to the superposition of two stages of deformation and metamorphism in South China, the Cathaysian system is strong in the east and weak in the west, strong in the south and weak in the north.
3) The tectonic dynamic metamorphic belt and intrusive rock belt are unevenly distributed. Because Cathaysian system spreads to different blocks, strong tectonic dynamic metamorphic belt and intermediate-acid intrusive rock belt are often formed between different blocks in the diffusion area, such as dynamic metamorphic-migmatite belt and granite belt on the west side of Wuyishan-Yunkailong fold belt; Eastern margin of Dabie-Jiaonan high-pressure ultrahigh-pressure dynamic metamorphic belt; Zhangguangcailing-Laoyeling tectonic magmatic rock belt, etc. At the same time, large-scale fault zones with ductile shearing generally exist, and they generally have inherited activities, which obviously control the lithofacies structures in Paleozoic and early Middle Triassic.
4) The Cathaysian tectonic system has undergone a strong compound transformation. After the Cathaysian system was formed, it was displaced or deformed by the complex transformation of the later tectonic system, so its position was strange, or it followed intermittently, or formed an S-shaped, anti-S-shaped or arc-shaped distribution, such as Xuefeng arc, Jiuling arc and Yangchun S-shaped syncline. In addition, after the formation of Cathaysian uplift fold belt and depression fold belt, they suffered from strong uplift for many times, resulting in multi-stage and multi-level lateral detachment, which often showed that the uplift belt slipped to the lateral depression belt, but mainly pushed to the northwest foreland depression, forming arc structures such as Xuefeng and Jiuling or nappe structure belt of Longmenshan belt.
5) Cathaysian tectonic belt plays an important role in controlling lithofacies formation and sedimentary minerals in Paleozoic and early Middle Triassic, Caledonian and Indosinian magmatic belts and related endogenous and metamorphic minerals. Such as Paleozoic iron, coal and marine oil and gas. Oil and gas are generally found in Paleozoic and Middle-Lower Triassic shallow-sea sedimentary deposits in South China controlled by China Xia Hai Trough. The gentle uplift area with little structural change and the nappe area with Mesozoic nappe structure may be favorable marine oil and gas accumulation areas.
6) The main tectonic belts (belts) of Cathaysian tectonic system are obviously reflected in the deep structure, but mainly the NE-trending mantle uplift (depression) belt corresponds to the mantle slope belt, especially the corresponding arc mantle uplift belt (belt) such as Xuefeng-Jiuling Cathaysian arc uplift belt, and the crust thickness is 30~40km, indicating that they are regional tectonic systems in the deep part of the crust.