(I) Formation of the Carboniferous-Permian coal-bearing basin in South China

The South China Carboniferous Permian coal-bearing basin was developed on the basis of the South China continent in the middle and late Hualixi period. The South China continent consists of the Yangzi land mass and the South China activity belt. The Yangzi land mass was formed in the Sibao-Jinnings period and has been relatively stable for a long time. The South China Activity Belt is a Neoproterozoic-Early Paleozoic rift zone above the Yangzi landmass and the Huaxia paleolandic crust, which closed during the Caledonian movement and formed the paleo-South China continental crust with the Yangzi landmass.

The tectonic deformation of the South China continent is complicated, and in the Sibao-Jinnings period, the Yangzi land margin successively coalesced with the Huaxia, North China, and Indo-Chinese palaeocontinent in three directions to form the main body of the north-east, east-west, and near-north-south orogenic belts, which laid down the palaeo-tectonic structure of the South China continent.

The Caledonian orogeny in the northern part of the main performance of Wuyi, Wugong - Zhu Guang block along the Shaoxing - Pingxiang - Beihai line for the A-type subduction splicing, the first to the north, and then to the west, the formation of three kinds of deformation style. The first deformation was "S" arc-shaped spread, including Wuyi, Wugong, Yue Cheng Ling arc fold belt. The second type of deformation is superimposed across the orogenic belt of the north-north-west converted fold belt, a dense linear spread. The third type of deformation is a relatively open north-east oriented superimposed fold. In the south, there is an east-west basal fault with transform nature in the Yishan-Quannan area, reflecting the dynamics of northward convergence of the Lingnan block.

The South China Rift closed at the end of the Caledonian to form the Caledonian Fold Belt, and the Yangzi land mass collocation, collocation of the South China continent at the end of the Late Silurian sea recession, uplifted to the land, to the beginning of the Devonian and subsidence of the sea invasion, seawater from the south to the north, the northeast direction of the expansion of the development of the alternating sea-land and land-phase sedimentary stratigraphy. Marine stratigraphy for the stable shallow sea, coastal sedimentation, from the southwest to the northeast of the gradual increase in clastic rocks, Devonian sedimentation along with the gradual expansion of the sea invasion, from bottom to top for the conglomerate, sandstone, mudstone, carbonate rock deposition of the cyclone, showing a complete sequence of sea into the sequence.

The Early Devonian in the paleoland margin or sedimentary depression zone to receive the land margin coastal deposition, and then replaced by extensive sea erosion, Yangzi, Kang Dian, Jiangnan and Huaxia paleoland between the near-coastal, shallow marine deposition. Early Devonian early seawater from the southwest, sea invasion scale is not large, in the middle and late seawater gradually deepen and expand to the north and east. In the Middle Devonian, the sea erosion expanded, the coastline migrated to the north and east, the sea erosion range expanded, and the terrestrial sedimentation range also expanded. The uplifted and denuded area of the Jiangnan paleoland received marine deposition, and the seawater crossed the Jiangnan paleoland, and there was also marine deposition in northwestern Hunan and western Hubei. The Late Devonian South China Sea continued to expand, and the terrestrial deposition also expanded. The eastern part of the South China Sea expanded to the east of Ganzhou, where the marine deposition was stable, and from west to east was marine-littoral- terrestrial deposition. Before the Carboniferous deposition at the end of the Devonian, seawater came from the Southwest of South China Sea, and the sea invasion was gradually expanded, and the sedimentary layer was expanded to the north-east direction one by one since the Early Devonian. The South China Sea is connected with the Indian Ocean in the southwest, and the western boundary is at the eastern edge of the Kangdian Paleoland, and the northern boundary is a line from Kunming to Guiyang, and then northward along the junction of Sichuan, Hunan, and Eu, and then northward to the middle reaches of Yangtze River Basin, and the eastern boundary is to Ganzhou. The ancient landmass of Jiangnan was spreading in the north area of South China Sea in a north-east arc-shaped peninsula. The Lower Yangzi land mass in the Late Devonian also appeared subsidence depression, for the terrestrial plains river and lake swamp phase clastic rock deposits, also known as the Wutong sandstone.

The Carboniferous sedimentary basins were developed on the Devonian paleogeographic background. Kang Dian, Upper Yangzi, Jiangnan, Huaxia paleorise continued to uplift and denudation, the sea erosion range is more expanded than the Devonian, the edge of the uplift sea erosion transition zone with land or sea and land alternate phase deposition. The Early Carboniferous sedimentary rock phases are more varied, with marine carbonate rocks, terrestrial clastic rocks and coal-bearing rock systems, while the Late Carboniferous sedimentary rock phases are more stable, dominated by marine carbonate rocks, and coal-bearing constructions are mainly developed in the Early Carboniferous.

In the Early Carboniferous, the South China Basin expanded and the land area shrunk, the Kangdian and Upper Yangzi Palaeoland retreated to the west, the Huaxia Palaeoland retreated to the east, and the Jiangnan Palaeoland changed from a curved peninsula to a long island in the sea, and the seawater of the Dianqian-Guizhou Basin extended northeastward through the Ganzhe to the Lower Yangzi Sea, and the Huaxia Palaeoland was separated from the Yangzi Palaeoland and the Jiangnan Palaeoland, and the western Palaeotethystic Sea was connected to the Yangzi Sea along the Qinling Mountains, which extended to the Huai'nan. The The South China Sea is a carbonate-dominated shelf sea, from the edge of the land to the center of the basin carbonate phase with a regular spread, the Early Carboniferous interland sea of the western and northern coastline is located in Kunming, Guiyang, Wuhan, Chaohu to the north, the eastern shoreline in the western edge of the Huaxia Paleocontinent, the southwestern shoreline along the Niusoushoushan Paleocontinent, Kang Dian Paleocontinent east and south boundaries and the distribution of the northern edge of the Mabing Paleocontinent. In the northern part of the basin, the Jiangnan Paleoland is a huge island spreading in a north-east-east direction, and there are carbonate terraces along the edge of the coastline, and the neighboring Paleoland is tuff, marl, shale and sandstone with a short period of coal-bearing environment in the swampy plains. In the Xuefeng Paleoland, south of the Jiangnan Paleoland, the formation of deltaic sedimentary phase, and the land margin of the shallow water carbonate deposition alternating transition, coupled with the warm and humid climate vegetation flourished, creating a good coal-forming conditions, the formation of a good coal-bearing construction. The western edge of the Huaxia Paleocontinent also developed alternating land and sea-phase coal-bearing deposits, and the land-phase was dominant from the east to the Paleocontinent slope zone. The shallow sea area far from the shore formed the Guanghai terrace phase zone and the inter-terrace groove and isolated terrace.

Late Early Carboniferous (Daitang period) in southern China, the southern part of the continent was in the period of sea invasion, seawater intrusion from the southwest and northeast, distributed in the east of the Kangdian Paleocontinent, the southern part of the Yangzi Paleocontinent, the southwestern part of the Huaxia Paleocontinent. The coal-bearing rock systems formed during the Datang period were widely distributed, but the coal-bearing area was not extensive, mainly in central Hunan, northern Gui, southeastern Hunan, northern Guangdong, eastern Guangdong, central-southern Gan and eastern Yunnan. The coal-bearing rock systems developed in the early Daitang period were distributed in the eastern margin of the Kangdian Paleocontinent in the western part of the South China continent in the areas of eastern Yunnan, northeastern Yunnan, northwestern Guizhou, and southern Qiannan, with the Wanshoushan Formation in the eastern part of the country, and the Xiangpeng Formation in southern Qiannan. With the overtopping of seawater to the northeast, the Datang Intermediate Coal-bearing Rock System was formed in Gui, Xiang, Guangdong, Gan, Min and Zhejiang at the periphery of the Yangzi Paleocontinent and Jiangnan Paleocontinent. The mid-Datang coal-bearing rock system has good coal-bearing properties, and Lianyuan, Shuangfeng, and Shaoyang in central Hunan are coal-rich centers with coal seam thicknesses greater than 2 m. There are also good coal-bearing areas in central Gan, northern Guangdong, and northern Gui. The coal-bearing rock system in central Hunan and northern Guangdong is the water-testing group. In the Lower Yangzi region, seawater comes from the northeast, and weak coal aggregation has also occurred, and there are also mineable or partially mineable coal seams, and the coal-bearing rock system is the Gao Li Shan Formation.

The sedimentary rock phases of the Datang Period consist of various sedimentary phases such as shallow marine phase, bay phase, tidal flat-beach phase, delta phase, barrier-lagoon phase, zigzag river-lake deposition, and alluvial fan-braided river. The middle and lower parts of the Lindi Formation, Zhongxin Formation and Yejiatang Formation in southwest Fujian, northeast Guangdong, east Jiangxi and west Zhejiang at the edge of the Paleoland belong to the alluvial fan-braided river phase. The middle and lower parts of the Zhangshan Formation, the middle part of the Zhongxin Formation, the middle part of the Wanshoushan Formation, and the middle part of the Xiangpeng Formation in northeast Yunnan, Qiannan, northeast Hunan, northeast Gan, and east Guangdong at the margin of the Paleolithic Land are deposited in the zigzag river-lake phase. The middle part of Lianyuan-Shaoyang in central Hunan and the middle part of Measuring Water Formation in Qujiang in northern Guangdong are barrier-lagoon phase deposits, and the middle and lower parts of the Simen Formation from Lipo in southern Guizhou to Huanjiang in northern Gui, and Liucheng-Luzhai in Liucheng belong to delta phase deposits. The early stage of the Datang in eastern Yunnan and Qiannan, and the middle stage of the Datang in the Lower Yangzi region are the most widely distributed tidal flat-beach phase deposits in the South China Basin. The middle stage of the Daitang in northeast Gui, central-south Hunan, northwest Guangdong, and some parts of Hubei is a bay phase deposition.

The late Early Carboniferous Datang to Late Carboniferous sea erosion is a larger sea erosion in the South China Sea since the Paleozoic era, the sea range is expanded, the denudation area is narrowed, and the ranges of Kangdian Palaeocontinent, Yangzi Palaeocontinent, and Huaxia Palaeocontinent are all narrowed. Due to the expansion of the sea area, the Exi Gulf extends westward to east Sichuan, Longmenshan Gulf and Yanyuan-Lijiang shallow sea area intrudes eastward, Huaxia Paleoland retreats southeastward, and the range is narrowed, and there are shoreline clastic deposits at the edge of the Paleoland, and near the upper Yangzi, Xuefeng, and Kangdian Paleolands are shoreline tidal flat area, and the rest are shallow sea carbonate rock dominated by the open terrace phase area. Late Carboniferous South China continental coal gathering role is basically interrupted.

The Early Permian paleogeography of the South China continent inherited the Late Carboniferous outline, and it was still a stable land-shelf shallow marine phase deposition. In the early Early Permian, seawater intruded from both the southwest and northeast, and the range of the Jiangnan and Kangdian paleolands narrowed, with the Upper Yangzi Sea and the Southeast Shallow Sea connected, and the Qianzhong Underwater Rise south of the open carbonate plateau and north of the confined sea. The Qixia Formation developed in the middle of the Early Permian is a set of shallow-sea carbonate deposits, and the Liangshan Formation in the lower part of the Qixia Formation in the west-central part of the South China Sea is a coastal-phase coal-bearing clastic rock and bauxite. Its distribution is smaller than the range of Carboniferous coal-bearing rock systems, smaller than the subsequent Permian coal-bearing rock systems, mainly distributed in the Xuefeng Paleoland to the north of Southwest Ezhou - Northwest Hunan, West Qianyang - Xupu, for the lagoon and bay phase deposition, the Jiangnan Paleoland to the north of Southeast Ezhou, Puqi-Chongyang, Northwest Jiangxi Xiu Shui, is also a lagoon and bay phase deposition. The lagoon and gulf phase deposition. Distributed in the northeast of the Niushoushan paleoland Zhaotong - Yiliang, Qianxi Weining - Hezhang, for the coastal alluvial plains phase deposition, coal-bearing better.

The Dongwu movement at the end of the Early Permian in the South China continent had a wide range, and had an intra-land orogenic nature in the southern section of the Qinzhou-Yunkai and Wuyishan Mountains, and the residual troughs of Qinzhou Bay and the Qiongzhong Rift Trough were also closed at the end of the Early Permian and the Late Permian. The early Late Permian was a period of major sea retreat, and the sea water in South China retreated into the Indian and Pacific Oceans. Although the South China Land Shelf Sea is relatively stable, but due to the influence of the Dongwu movement, the Yangzi land mass crust generally rise, the sea water has retreated, Kang Dian paleoland, Huaxia paleoland range has been expanded, between the two paleoland development of the shallow sea carbonate rocks, the lower part of the development of coal-bearing clastic rocks, in the paleoland on both sides of the vast coastal plains, the seawater in and out of the formation of coastal swamps and depositional environments, which is favorable for coal gathering. In the western part of the South China land mass, the early Late Permian until the Late Permian Changxing period, there is a large scale Emeishan basalt overflow, the South China continent occurred in the Permian last sea invasion, seawater diffuse all over the region, for the normal shallow oceanic deposition, the coal gathering interrupted.

Late Early Permian, South China mainland east of YunKai ancient land to the east, WuYi ancient land to the south, HuaXia ancient land to the northwest, the ancient land around the limit of the sea basin in the development of sea and land alternate phase coal-bearing deposits. The coal-bearing rock systems are the Lower Permian Tongziyan Formation, Lixian Formation, Shangrao Formation and Yanqiao Formation, which are mainly distributed in the area of central Fujian, southwestern Fujian, western Zhejiang, eastern Gan, eastern Guangdong and central Guangdong. The lithology is siltstone, shale with fine sandstone, locally sandwiched with thin layers of tuff or tuff lenses, sandwiched with multiple layers of recoverable coal, 200-977 m thick, and the coal-bearing rock strata are distributed in the alternating phase of the sea and land. Tongzilan sedimentation is mainly developed in Wuyi, Huaxia two ancient land in the basin between the early and middle development of the bay - shallow marine deposition throughout the region, the early development of the former delta - delta margin phase and barrier lagoon phase deposition, along the northwest edge of the Huaxia ancient land, the southeast edge of the Wuyi ancient land in the north-east to spread, the two types of phases are superimposed on each other. The lower delta-delta front sedimentary phase developed in the early and late stages of the Tongziyan, transitioned to barrier-lagoon deposition in the seaward direction, and transitioned to alluvial fan-upper delta plain deposition in the landward direction, which was adjacent to the Huaxia Paleocontinent in the early stage, and distributed in the southeast side of the Wuyi Paleocontinent in the late stage. The coal-bearing nature of the Tongziyan Formation has obvious differences, bounded by the line of Shanghang-Mingxi-Jiangle-Shangrao-Jiande, with the west side containing no coal or no recoverable coal, and the east side containing good coal, i.e., the coal-bearing beds are mainly developed in the northwestern edge of the Huaxia Paleocontinent. For example, the two coal-rich centers of Datian and Yongchun in Fujian, the thickness of recoverable coal is more than 9 m.

The end of the Early Permian, the East-Wu movement caused the general uplift of the South China continent, seawater retreat, the uplift of the Kandian Paleocontinent and the Huaxia Paleocontinent, which enlarged the area, and the Kandian Paleocontinent and its peripheral basaltic rocks were overflowing, and the central part of the South China Basin in the Late Permian from the north to the south was constructed by the shallow-sea coal-bearing carbonate rocks, which were close to the Kandian and the East-West of the Huaxia Paleocontinent. The east and west sides of the Kangdian and Huaxia Paleoland are coal-bearing sandy mudstone deposits in the alternating phase of the sea and land, and the neighboring edge of the Paleoland is a terrestrial coal-bearing clastic rock deposit. The coal-bearing strata around the edge of the neighboring paleoland are Xuanwei Formation and Cuipingshan Formation, and the coal-bearing deposits in the central part of the basin are the alternating phase of sea and land, the Longtan Formation in the eastern part of Yunnan, Qianxi, and southern part of Sichuan, and the Leping Formation in the eastern part of Gan. Between the two sides of the paleoland is a coal-bearing rock system dominated by shallow coastal deposition, with the Wujiaping Formation in east Guizhou, east Sichuan, and north Gan, and the Heshan Formation in central Gui. At the end of the Late Permian, during the Changxing period, except for the east side of the Kangdian Paleoland, where there were localized coal-bearing rock systems with alternating land and sea phases, the mainland of South China was composed of Changxing Formation or Dalong Formation with shallow marine carbonates and siliceous rock deposits.

The Late Permian coal-bearing rock systems in the western part of the Yangzi Paleocontinent, the sedimentary rock phase zone from the edge of the Paleocontinent to the sea gradually transitioned from the alluvial fan - braided river phase to the varved river - lake phase of the deposition. There are deltaic phases and clastic shoreline deposits in different parts of the broad land-sourced clastic shoreline zone. On the west side of the Yunkai Paleoland, there is a coastal fault trough, forming a huge thick coarse clastic sedimentary assemblage. The coal-bearing rock system in the western part of the Late Permian Yankai Paleoland has good coal-bearing properties, and the Longtan and Changxing phases have formed multi-layer recoverable coal, which contains thin to medium-thick coal seams of 1 to 109 layers in the coal-rich belt of Sichuan, Yunnan and Guizhou, and the coal seams in the area of Liupanshui-Zhiona in southern Sichuan and Chongqing-Guizhou and western Guizhou have a cumulative thickness of more than 10 m, with recoverable seams of more than 40 m thick. To the east to E, Gui, western Hunan region coal-bearing deterioration, coal seams are produced at the bottom of the coal-bearing rock system. The early coal-bearing rock system of Longtan has a wide distribution area, containing 2 to 3 layers of recoverable coal, and there are coal-rich belts in Chongqing and Liupanshui with a thickness of more than 5 m. The middle coal-bearing rock system of Longtan is slightly smaller than the middle coal-bearing rock system. The middle stage of Longtan coal-bearing area is slightly smaller than the early stage of Longtan, with 2-5 layers of recoverable coal, but the coal-rich zone is enlarged compared with the early stage of Longtan, and there are coal-rich zones in Chongqing, Zijin, Liuzhi-Panxian. The coal-bearing area of the late Longtan period is smaller than that of the middle period, with 3 layers of recoverable coal and two coal-rich belts in Liupanshui and Shizong. In Changxing period, the sea area was large, but the coal-bearing area was much smaller than that of Longtan period, with 1-3 layers of recoverable coal, and the coal-rich belt was close to the Gulushuicheng-Panxian belt. From the Longtan period to the Changxing period, the distribution of the coal-rich zone gradually migrated to the west in the direction of the ancient land, the Longtan early and middle period is located in the southeast of Sichuan - northwest of Guizhou, Qianxi area, the Longtan late period is located in the area of Qianxi to the east of Yunnan Province, and the coal-rich zone in the Changxing period is more obvious westward migration, located in the area of Shucheng-Panxian.

Toward the end of the Early Permian, the Dongwu Movement caused great changes in the paleogeography of the South China continent, with the uplift of the Kangdian Paleocontinent and large-scale basalt overflow, and the uplift of the Yunkai Paleocontinent and the Huaxia Paleocontinent, which enlarged the land area and narrowed the scope of the sea area, and with the change of the sea basin, the sea and land alternating-phase depositional environment along the edge of the paleocontinent formed, which resulted in the Early Late Permian Permian coal-bearing basin in South China.

The coal-bearing basins developed in the late Early Permian in the Yunkai, Wuyi, and Huaxia interland basins were still in coal-bearing depositional environments in the Early Late Permian, but there were great differences in coal-forming conditions between the northwestern edge of the Huaxia Paleocontinent and the southeastern edge of the Wuyi Paleocontinent and the southern edge of the Paleocontinent. The Cuiping Mountain Formation in southwestern Fujian and northeastern Guangdong, the Wulin Mountain Formation in northeastern Jiangxi, the Entan Formation in western Zhejiang, and the Shahu Formation in central Guangdong are terrestrial and marine clastic deposits consisting of sandstones, siltstones, mudstones and claystones, and the bottom gravelly coarse sandstones are in pseudo-consolidated contact with the Lower Permian Tongzi Rock Formation, which is 142-672 m thick. The coal-bearing nature of this rock system is poor, and except for the locally recoverable coal in the western part of the basin, the rest of the area is all thin coal seams or coal lines. The coal content of this suite is poor, except for the local recoverable coal in the west, the other areas are all thin coal seams or coal lines. It is distributed in the southeast of Wuyi Paleoland in the west of Zhejiang, west of Fujian, southeast of Gan, and east of Guangdong, and the quzhouliu river-lake phase deposition is spreading in a long strip parallel to the paleoland. Distributed in the southwestern end of Wuyi Paleoland in southeastern Hunan, Leiyang, Yongxing, and the northern end of Yunkai Paleoland in southern Changning and Fengcheng and Xinkan in central Gan, the delta-phase deposition. Developed in the early and late Longtan period, it is distributed in Ganzhong and the area around the Lower Yangzi, South Anhui, Southeast Hubei, and South Jiangsu, and the shoreline deposition of non-deltaic clastic rocks is spreading in the form of a belt. Developed in the early and late Longtan, distributed in Xiangzhong, northern Guangdong, central Guangdong, western Guangdong for the Gulf sedimentary phase, distributed in northern Gan, southern Anhui for the coastal shallow marine sedimentation. The southeastern part of the Late Permian coal-bearing basin in South China has better coal-bearing properties. The lower coal-bearing section of the Longtan Formation generally contains recoverable coal seams and has the best coal-bearing property; the upper coal-bearing section mostly contains recoverable coal seams and has relatively poor coal-bearing property. The better coal-bearing areas are the periphery of Wuyi Ancient Land, Xiangzhong, Xiangdong, Ganzhong, northern Guangdong, western Guangdong, southeastern Gan, and the areas around southern Anhui, northern Zhejiang, and southern Jiangsu.

The South China Carboniferous Permian coal-bearing basin was developed on the basis of the South China continent. The South China continent was formed by the merging of the closed Huaxia Rift Belt in the Caledonian period with the stable Yangzi land mass and the Huaxia Paleoland. The South China continent, with the Yangzi land mass as its core, converged with neighboring plates or land masses in multiple phases and directions, and the orogenic belts, deformation belts, and intra-plate deformations formed by the plates were the results of the comprehensive balance of multiple stress systems.

Before the Caledonian period, the Yangzi land margin successively coalesced with the Huaxia, North China, and Indo-Chinese palaeocontinent in three directions, forming the north-northeast, east-west, and near-north-south orogenic belts, which laid down the palaeotectonic framework of the South China continent. The Caledonian orogeny is the inheritance of the power system and paleotectonic pattern since the Neoproterozoic, and also the tectonic background of the paleogeographic formation of the South China continent after the Caledonian. The Yangzi landmass and the Huaxia landmass were formed in the Neoproterozoic Jinning period, the North China landmass was formed in the Paleoproterozoic Luliang period, and the formation of the South China continental landmass was later than that of the North China landmass. South China continent is the Neoproterozoic - Early Paleozoic rift zone at the end of the Caledonian closure with the Yangzi land mass collocation, North China land mass since the Aurignacian has been in the land mass of the development of a unified land surface sea, the mid-Caledonian uplift as a whole for the land, the South China continent of the pre-Aurignacian basement by the Yuan Guyu metamorphic system, South China continent basement rigidity is weaker, the basement of the North China land mass is more rigid, thus The basement of the South China continent is weaker and the basement of the North China continent is more rigid, which leads to the difference of the interplate force in the intra-land stress field, the tectonic deformation of the North China landmass is dominated by the difference of the block breakage and the South China continent is dominated by the flexible deformation of the fold. From the North China land mass and South China continent two land mass stress field analysis, the former is more unidirectional, simple, the latter is relatively multi-directional, complex. North China land mass in China before the formation of the ancient continent, mainly belongs to the ancient Asian tectonic domain, to the north-south extrusion stress, and the Indo-Pacific tectonic domain after the Indo-Chinese period, to the Kula - Pacific plate on the Eurasian continent of the north-west subduction for the dominant direction of stress, from the Siberian plate and Indian plate north-south extrusion stress has been relegated to the second. Whether it is the period of consolidation of the Yangzi and Huaxia Palaeocontinents before the Hualixi Period or the activation since the Middle Cenozoic, the stress field of the South China continent is centered on the Yangzi Plate, with the force coming from the Pacific Plate, the Siberian Plate, and the Indian Plate, which forms the tectonic lines of the north-north-east, east-west, and north-south directions, and has resulted in a variety of tectonic styles of the old and new deformations intertwined and superimposed, which is the basic geodynamic mechanism of the formation of the Coal-bearing Basin of the Carboniferous Permian and the later evolution of the South China Plateau. This is the basic geodynamic feature of the formation and later evolution of the Carboniferous Permian coal-bearing basins in South China.

The South China Rift closed at the end of the Caledonian to form the Caledonian Fold Belt, which joined with the Yangzi land mass, and the combined South China continent rose to land at the end of the Late Silurian, and then sank into the sea at the beginning of the Devonian. Early Paleozoic early South China's vast sea, the periphery of the Kang Dian, Yangzi, Jiangnan, Huaxia ancient land range from time to time, but the area is always shrinking, to the early and middle Zhiliu Shi, especially late Zhiliu Shi, South China's continent, in addition to the northern part of a shallow sea stretching from east to west and the southern half of the deep sea trough of Qinzhou, has been uplifted to the land, become a sedimentary basin of the Devonian period before the formation of the paleogeographic background of South China's continent. In the early Devonian, the South China Sea expanded westward only on the basis of the Qinzhou Trough, and the seawater infiltrated the periphery of the Kangdian Paleoland, and the depositional range was in the south of Yunnan, Guizhou, Gui, and Xiang. The Middle Devonian seawater continued to advance to the north and east, only Hainan Island in the south - Yangjiang residual island arc, seawater expansion to the north and extend to the south of the Yangtze River northwest of the Xiangjiang River, and to the east to the Ganxi area. To the late Devonian Jiangnan paleoland narrow peninsula is located in the northern waters of the South China Basin, the Lower Yangzi seawater has been intruded from the northeast. During the Devonian, the Kangdian Paleoland, Huaxia Paleoland, and the Upper Yangzi Paleoland were always in the stage of uplift and denudation, and the South China Basin was mainly distributed to the east of the Kangdian Paleoland, to the south of the Upper Yangzi Paleoland, as well as between the Upper Yangzi Paleoland and the Gangnam Paleoland, between the Gangnam Paleoland and the Huaxia Paleoland and the region around the Lower Yangzi. The Lower Yangzi seawater comes from the eastern Pacific Ocean, and the Upper Yangzi seawater comes from the Indian Ocean. The South China Sea gradually expanded from southwest to northeast, and the extent of the sea basin was also from small to large. The pattern of sea-land distribution in South China at the end of the Devonian is the paleogeographic background of the Carboniferous Permian coal-bearing basins.

During the Carboniferous period, the South China continent followed the paleogeographic pattern at the end of the Devonian, and the western and northern boundaries of the South China Basin were the Kangdian Paleoland and the Upper Yangzi Paleoland. The Upper Yangzi Paleoland has been in a state of uplift and denudation in the Carboniferous period, and the seawater intruded locally in the Late Carboniferous period until the Permian period when it was submerged by the seawater. The Huaxia Paleoland on the southeast boundary of the South China Sea has been greatly reduced since the Devonian, and the range of the Paleoland was even more retreated in the Carboniferous. Since the Early Carboniferous, seawater from the Southwest Indian Ocean crossed the paleoland and communicated with seawater from the Northeast Pacific Ocean, until the Jiangnan paleoland in the northeast of the South China Sea and the wide range of the Upper Yangzi paleoland in the west in the Late Permian, when the area of the paleoland shrunk with the continuous expansion of the sea. Early Permian and Late Permian, except for the peripheral paleoland and a few intermediate paleo-islands, seawater encroached on almost the entire area. Located in the northeast of the South China mainland, the Lower Yangzi ancient land, the late Devonian subsidence for the land basin, to the early Carboniferous began to communicate with the sea water from north to south to become a part of the South China Sea.

Southern China Carboniferous, Permian sedimentary rock phases, the early Carboniferous for the marine transition type of deposition, isolated terrace and grooves siliceous carbonate ping clastic rock construction, shallow sea terrace carbonate rock folder volcanic rock construction, coastal shallow sea carbonate rock construction, the alternating phases of the land and sea containing coal construction. The types and distribution of sedimentary phases in the Late Carboniferous and Early Carboniferous are basically similar. In the Early Permian, there was regional sea intrusion, and the sedimentary phases were quite different from those of the Carboniferous, but the phases tended to be single, mainly shallow-sea carbonate rock construction, and only in the western edge of the Huaxia Paleocontinent, there were shallow-sea clastic rock and carbonate rock or coal-bearing construction in the alternating phase of the sea and land and the sedimentary phase of the transitional type of the marine phase. In the middle of the Late Permian, shallow marine coal-bearing carbonate rocks and siliceous rocks were built, and in the east and west sides near the Huaxia and Kangdian paleolands, the coal-bearing sandy mudstone was built in the alternating phase of the sea and land, and in the Kangdian paleoland and its east side, there were also basal eruptive rocks. At the end of the Late Permian (Changxing period), there was also a sea erosion throughout the region, which was constructed as shallow sea carbonate rocks. Carboniferous to Permian sedimentary lithology development overall constitute a sea into the sedimentary sequence, reflecting the sea basin began to sink from the southwest, and then to the north and east expansion, to the Permian South China continent is based on the overall uplift, wave-like folding of the main, so that the whole land mass subsidence to form the vast South China Sea Basin. Due to the complex geological structure and multi-directional tectonic stress system in which the South China continent is located, the performance of different tectonic parts in different periods is different, and the tectonic conditions of coal-bearing construction must be formed in a certain period of time, resulting in the oscillation of the crust, resulting in the regional and phased lifting and lowering of the crust, the inward and outward movement of seawater to form the sea and land alternation or land-phase deposition, and at the same time there is a favorable coal-forming environment for preserving the coal-forming organic materials, thus At the same time, there is a favorable environment for coal-forming organic materials to be preserved, thus forming coal-bearing basins. In the Carboniferous period, the South China continent was mainly deposited in the marine phase, and only in the Early Carboniferous period, there were better coal-bearing construction. Although the Early Carboniferous coal-bearing basins had a wide range, spreading all over the Early Carboniferous depositional area, the sea basin of the early Carboniferous period was confined in the southern part of Upper Yankton Paleodecadal land, and thus Sichuan and its neighboring areas were in the uplift denudation area, and the Early Carboniferous coal-bearing basins did not spread over the whole South China continent. Late Carboniferous with the expansion of the sea invasion, until the early Permian, including the Upper Yangzi Paleoland all become the sea basin, Ma Ping period (Funan period) deposited shallow sea carbonates, the Upper Yangzi Paleoland of Sichuan, Yunnan, Guizhou and Guizhou, a short-term crustal uplift and oscillation, the formation of the Liangshan period of coal-bearing rock system. The stratum of Liangshan Formation is only 3-22 m thick in the middle of Sichuan, the lower part of which is light gray and purple clay shale, locally enriched in oolitic and bean hematite, the middle part of which is gray ferroaluminous mudstone and bean bauxite, and the upper part of which is brown and black charcoal shale sandwiched by coal beds. The Early Permian coal-bearing basins were developed for a short period of time, and the coal-bearing rock system was relatively thin, and the distribution of the basins was different from that of the Early Carboniferous coal-bearing basins, which were mainly located in the western part of the South China continent around Sichuan, Yunnan and Guizhou. In the late Early Permian, after the deposition of Qixia-period shallow sea carbonates, in the eastern part of the South China continent, the sea area sandwiched between the Huaxia and Wuyi Palaeocontinents, there was a crustal uplift and oscillation, and the coal-bearing rock system of the Tongzili period was deposited, which formed the coal-bearing basin of the Late Early Permian, and also the Mr. Late Permian coal-bearing basins. Due to the overall uplift of the South China continent, the seawater of the whole basin retreated to form the Late Permian (Longtan or Leping Stage) coal-bearing basin, which became a region-wide coal gathering effect. After this, the Changxing Stage sea erosion at the end of Permian deposited the shallow marine carbonate rocks of the Changxing Formation, which covered the Longtan coal system. During the Changxing Period, coal-bearing deposits were only found at the eastern margin of the Kangdian Paleoland. The Early Carboniferous, Early and Late Early Permian, and Late Permian coal-bearing basins in South China were superimposed on top and bottom of each other, with relative displacements, suggesting that the undulating depression and differential uplift of the basement of the South China continent during the Hualixian period resulted in the advancement of seawater in the basins and migration of the subsidence centers, causing the Carboniferous Permian coal-bearing basins to be born in different locations at different times.

See "Late Permian Wujiaping Stage Petrographic Paleogeographic Map of the South China Basin", "Late Permian Changxing Stage Petrographic Paleogeographic Map of the South China Basin", and "Permian Coal-bearing Basin (Prototypical) in South China", in the "China Coal-bearing Basin (Prototypical)", in the "China Coal-bearing Basin (Prototypical)". Basin (Prototype) Coal Concentration Zone Migration Schematic".