- Email: [email protected]
Environmental Change and Tectonics of China Continent in Mesozoic - Cenozoic
812
RODINIA, GONDWANA AND ASIA
On the Intraplate Deformation of China Continent Tianfeng Wan China University of Geosciences, Beijing 100 083, China Intense folding, faulting and magmatism, with different tectonic orientations in different stages are widespread in the upper part of China Continent. Investigations in this region led to the finding that the China Continent is an unstable and nontypical platform or craton, and is a paraplatform with polycycle movements (Huang, 1945; Ren, 1996). The region is characterized by several faulted blocks, a number of activation platforms or geodepressions (diwa) (Chen, 1960), intra-platform folding zones, tectonic systems (Lee, 1939) and intra-continental orogenic belts. Strong intraplate deformations, especially those developed in Mesozoic-Cenozoic were recorded in many previous studies. This intraplate deformation constitutes a fundamental topic of interest in the China Continent. Studies in the last 15 years provide the following clues for the intraplate deformation: (1) The cratons, continental crystalline blocks, which make up the China Continent, are too small and so unstable (Ren, 1996). (2) The pattern of movement of surrounding plates were different in many times from Mesozoic to Cenozoic. Sometimes, the blocks dispersed from Gandwana moved and collided to the northward (in Triassic, 250-208 Ma; Early Cretaceous-Early Eocene, 135-52 Ma; Miocene-Early Pleistocene, 23.3-0.78 Ma; and recent, since 0.78 Ma), and sometimes the oceanic plates (Izanagi, Pacific and Philippine Sea plates) were subducted to the westward
(in Jurassic-Earliest Cretaceous, 208-135 Ma; Middle EoceneOligocene, 52-23.3 Ma; and recent, since 0.78 Ma; Wan, 1994; Wan and Zhu, 1997). (3) The sedimentary cover shows large thickness in most areas of China Continent, thus the strength of upper part of crust is rather weak which might have triggered the intraplate deformations. The intraplate deformations of the Chinese continental lithosphere can be explained based on the various above parameters, as well as tectonic and magmatic processes.
References Chen Guoda (1960) The Activation Platform and its influence to predict the ore deposits. Geol. Publ. House, Beijing (in Chinese), pp. 1-408. Huang, T.K. (1945) On major tectonic forms of China. Geological Memoirs, (in English with Chinese summary of 11pages), No. 20, pp. 1-165. Lee, J.S. (1939) The Geology of China. Tomas Murby and Co., London, pp. 1-528. Ren Jishun (1996) The continental tectonics of China. J. Southeast Asian Earth Sci., v. 13, pp. 197-204. Wan Tianfeng (1994) Intraplate deformation, tectonic stress field and their application for eastern China in Meso-Cenozoic. Press of China University of Geosciences, Wuhan, pp. 1-156. Wan Tianfeng and Zhu Hong (1997) On the accretion of Eastern Asian continental blocks since Triassic. J. China Univ. Geosci., v. 8, pp. 114.120.
Environmental Change and Tectonics of China Continent in Mesozoic Cenozoic Tianfeng Wan China University of Geosciences, Beijing 100 083, China, E-mail: [email protected] The China continent is composed by many small crustal blocks, which were active during various periods in the geological history. Many of above small blocks were amalgamated in the Triassic (248-208 Ma, Indosinian tectonic stage), and belong to the Eurasian continental plate (Huang and Chen, 1987; Metcalf, 1995; Wan and Zhu, 1991; Wan, 1994, 1997). In the end of Triassic, the main mountain ranges (such as Yinshan, Qinling-Dabie and Kunlun) formed and orientated in east - west (in recent orientation), and the shallow sea developed in south China area and the great inland basin formed, with warm and dry weather in north China. By the influence of the Izanagi plate (Maruyama and Seno, 1986; Moore, 1989), the NNE trending high mountains (>3000 meters), with strong folding, thrusting, magmatism and many ore deposits (constituting 35 Yo of the ore deposits in China), were formed in the eastern China continent (Wan, 1994). This
coincided with the main tectonic stage, called Yanshanian tectonic stage (208-135 Ma, Jurassic-Earliest Cretaceous; Weng, 1927; Lee, 1929). However, at that time, the plains and hills, with a lot of rivers and lakes, were developed in the western China continent and a rather warm and wet climate prevailed. A number of coal deposits were also formed, and the biggest coal field was formed in Ordos area. From the main stage of Cretaceous to Early Eocene (135-52 Ma, Sichuanian tectonic stage; Lee, 1950; Wan and Zhu, 1989), by the influence of the northward moving blocks of Gandwana, a series of NWW trending folds, thursts and mountains, NNE trending normal faults and basins were developed in whole of China continent. The climate was rather hot and dry in the main area of China, except the northeastern China area. It was during this time that another 35 Yo ore deposits of China were formed (Wan, 1994). Gondwana Research, V. 4, No. 4, 2001
RODINIA, GONDWANA AND ASIA
The Pacific plate began to subduct to the eastern part of Asian continent by about 30 Ma (Uyeda, 1977; Sen0 and Maruyama, 1984; Maruyama and Seno, 1986). Westward compression and N-S extension occurred in the eastern China continent in the Middle Eocene - Oligocene ( 5 2 - 23.3 Ma, North Sinian tectonic stage). This led to the formation of three mountain ranges with east-west orientation (recent Yinshan-Yanshan, Qinling-Dabie and Nanling mountains began to form) and four original drainage basins. It also marks the main stage of formation of oil and gas in China (Wan, 1994, 1995). The weather of eastern part in China continent since that time was controlled by the Pacific Ocean. The Himalayan Mountains, Tibet-Qinghai plateau, Yangtze and Yellow Rivers all formed in the Himalayan tectonic stage (23.3 - 0.73 Ma, Miocene - Early Pleistocene; Huang and Chen, 1987; Wan, 1994, 1995). Since this time the weather of northwest area of China became very dry, leading to the development of widespread dry regions. The Neotectonic stage is marked by the Middle Pleistocene to Recent, when the migration of oil and gas, distribution of ground water in fractures, earthquakes and other geological hazards occurred (Wan, 1984, 1994). The fractures and faults, nearly paralleled to recent orientation with maximum principal compressive stress, changed to the high permeability zones, permitting easy flow of the underground water and oil and gas. While serving as pathways for other resources, they were also instrumental in triggering natural hazards.
References Huang Jiqing and Chen Bingwei (1987) Evolution of the Tethys Sea in China and its surrounding areas (in Chinese). Geological Publishing House, Beijing, pp. 1-78.
813
Lee, C.Y. (1950) On the Sichuanian movement. Bull. Geol. SOC.China, V. 30, pp. 1-8. Lee, J.S. (1929) Some characteristic structural types in eastern Asia and their bearing upon the problem of continental movement. Geol. Mag., v. 66, pp. 358-375. Maruyama, S. and Seno, T. (1986) Orogeny and relative plate motions: example of t h e J a p a n e s e islands. Tectonophys., v. 1 2 7 , pp. 305-329. Metcalfe, I. (1995) Gondwana dispersion and Asian accretion. Proceedings of the IGCP Symposium on Geology of SE Asia, Honoi, XI / 1995, J. Geol., Ser. B, No. 5-6, pp. 223-265. Moore, G.W. (1989) Mesozoic and Cenozoic paleogeographic development of the Pacific region. Abstract, 2Sth International Geological Congress, Washington, D.C., USA, v. 2, pp. 455-456. Seno, T. and Maruyama, S. (1984) Paleogeographic reconstruction and origin of the Philippine Sea. Tectonophys., v. 102, pp. 53-84. Uyeda, S. (1977) Some basic problems in the trench - arc - back arc basin system. In: Talwani, M. and Pitman, W.C. (Eds.), Island arcs, Deep sea trenches and back-arc-basin. Amer. Geophys. Union, Washington, D.C., Ewing Ser., v. 1, pp. 1-14. Wan Tianfeng (1984) Recent tectonic stress field, active faults and geothermal fields (hot water type) in China. J. Volcanol. Geotherm. Res., v. 22, pp. 287-300. Wan Tianfeng and Zhu Hong (1989) Tectonic stress field of CretaceousEarly Eocene in China. Acta Geologica Sinica, v. 2, pp. 227-239. Wan Tianfeng and Zhu Hong (1991) Tectonic events of Late ProterozoicTriassic in South China. J. South East Asian Earth Sci., v. 6, pp. 147-157. Wan Tianfeng (1994) Intraplate deformation, tectonic stress field and their application for Eastern China in Meso-Cenozoic. Press of China University of Geosciences, Wuhan, pp. 1-156. Wan Tianfeng (1995) On tectonogeomorphology of China. J. China University of Geosci., v. 6, pp. 64-70. Wan Tianfeng (1997) On the accretion of Eastern Asian continental blocks since Triassic. J. China University of Geosci., v. 8, pp. 114-120. Weng Wenhao (1927) Crustal movement and igneous activities in eastern China since Mesozoic time. Bull. Geol. SOC. China, v. 6, pp. 9-36.
Neoproterozoic Rifting History of South China Jian Wang and Chuang-Long Mou Southwestern Region, China Geological Survey, Chengdu 610082, China The integration of sedimentological, sequence stratigraphic and tectonic-stratigraphic data indicates that the Neoproterozoic South China Basins are characteristic of rifting and that their formation and evolution are closely related to the breakup of the supercontinent Rodinia. The basins can be divided into three provinces: southeastern Yangtze province, Kangdian province along the western margin of the Yangtze area and Cathaysian province and further subdivided into five subprovinces and eleven microprovinces on the basis of tectonic settings, sedimentary facies and palaeogeography, and outcrop sequence stratigraphy. Four genetic facies associations and two environmental facies associations which correspond to continental rifting events may also be recognized. The former include: (1) continental volcanic eruptive, ( 2 ) submarine volcanic eruptive, ( 3 ) tillite and (4) eustatic event deposits. The latter comprise: (1) continental and ( 2 ) marine environmental facies association. Gondwana Research, V. 4, No. 4,2001
The palaeogeographic evolution in the South China Basins has undergone four important stages. (1) the beginning of the early Neoproterozoic, i.e., the deposition of the Baizhu Formation and its equivalents Shiqiaopu and Luojiamen Formations, ( 2 ) The beginning of the middle Neoproterozoic, i.e. the deposition of the Sanmenjie Formation and its equivalents Yejia and Shangshu Formations, (3) The end of the middle Neoproterozoic, i.e. the deposition of the Chang’an Formation and its equivalents Changtan and Gucheng Formations and (4) The Late Neoproterozoic, i.e., the deposition of the Nantuo, Doushantuo and Dengying Formations. Four sequence sets have been identified in the Neoproterozoic successions in South China (Wang and Li, 2001), which correspond to continental rifting events. The basal boundary of Sequence set 1 represents the ‘Jinning-Sibao’ orogenic unconformity. Sequence set 2 is well developed throughout the South China Basins. This sequence set is built up of the
RODINIA, GONDWANA AND ASIA
On the Intraplate Deformation of China Continent Tianfeng Wan China University of Geosciences, Beijing 100 083, China Intense folding, faulting and magmatism, with different tectonic orientations in different stages are widespread in the upper part of China Continent. Investigations in this region led to the finding that the China Continent is an unstable and nontypical platform or craton, and is a paraplatform with polycycle movements (Huang, 1945; Ren, 1996). The region is characterized by several faulted blocks, a number of activation platforms or geodepressions (diwa) (Chen, 1960), intra-platform folding zones, tectonic systems (Lee, 1939) and intra-continental orogenic belts. Strong intraplate deformations, especially those developed in Mesozoic-Cenozoic were recorded in many previous studies. This intraplate deformation constitutes a fundamental topic of interest in the China Continent. Studies in the last 15 years provide the following clues for the intraplate deformation: (1) The cratons, continental crystalline blocks, which make up the China Continent, are too small and so unstable (Ren, 1996). (2) The pattern of movement of surrounding plates were different in many times from Mesozoic to Cenozoic. Sometimes, the blocks dispersed from Gandwana moved and collided to the northward (in Triassic, 250-208 Ma; Early Cretaceous-Early Eocene, 135-52 Ma; Miocene-Early Pleistocene, 23.3-0.78 Ma; and recent, since 0.78 Ma), and sometimes the oceanic plates (Izanagi, Pacific and Philippine Sea plates) were subducted to the westward
(in Jurassic-Earliest Cretaceous, 208-135 Ma; Middle EoceneOligocene, 52-23.3 Ma; and recent, since 0.78 Ma; Wan, 1994; Wan and Zhu, 1997). (3) The sedimentary cover shows large thickness in most areas of China Continent, thus the strength of upper part of crust is rather weak which might have triggered the intraplate deformations. The intraplate deformations of the Chinese continental lithosphere can be explained based on the various above parameters, as well as tectonic and magmatic processes.
References Chen Guoda (1960) The Activation Platform and its influence to predict the ore deposits. Geol. Publ. House, Beijing (in Chinese), pp. 1-408. Huang, T.K. (1945) On major tectonic forms of China. Geological Memoirs, (in English with Chinese summary of 11pages), No. 20, pp. 1-165. Lee, J.S. (1939) The Geology of China. Tomas Murby and Co., London, pp. 1-528. Ren Jishun (1996) The continental tectonics of China. J. Southeast Asian Earth Sci., v. 13, pp. 197-204. Wan Tianfeng (1994) Intraplate deformation, tectonic stress field and their application for eastern China in Meso-Cenozoic. Press of China University of Geosciences, Wuhan, pp. 1-156. Wan Tianfeng and Zhu Hong (1997) On the accretion of Eastern Asian continental blocks since Triassic. J. China Univ. Geosci., v. 8, pp. 114.120.
Environmental Change and Tectonics of China Continent in Mesozoic Cenozoic Tianfeng Wan China University of Geosciences, Beijing 100 083, China, E-mail: [email protected] The China continent is composed by many small crustal blocks, which were active during various periods in the geological history. Many of above small blocks were amalgamated in the Triassic (248-208 Ma, Indosinian tectonic stage), and belong to the Eurasian continental plate (Huang and Chen, 1987; Metcalf, 1995; Wan and Zhu, 1991; Wan, 1994, 1997). In the end of Triassic, the main mountain ranges (such as Yinshan, Qinling-Dabie and Kunlun) formed and orientated in east - west (in recent orientation), and the shallow sea developed in south China area and the great inland basin formed, with warm and dry weather in north China. By the influence of the Izanagi plate (Maruyama and Seno, 1986; Moore, 1989), the NNE trending high mountains (>3000 meters), with strong folding, thrusting, magmatism and many ore deposits (constituting 35 Yo of the ore deposits in China), were formed in the eastern China continent (Wan, 1994). This
coincided with the main tectonic stage, called Yanshanian tectonic stage (208-135 Ma, Jurassic-Earliest Cretaceous; Weng, 1927; Lee, 1929). However, at that time, the plains and hills, with a lot of rivers and lakes, were developed in the western China continent and a rather warm and wet climate prevailed. A number of coal deposits were also formed, and the biggest coal field was formed in Ordos area. From the main stage of Cretaceous to Early Eocene (135-52 Ma, Sichuanian tectonic stage; Lee, 1950; Wan and Zhu, 1989), by the influence of the northward moving blocks of Gandwana, a series of NWW trending folds, thursts and mountains, NNE trending normal faults and basins were developed in whole of China continent. The climate was rather hot and dry in the main area of China, except the northeastern China area. It was during this time that another 35 Yo ore deposits of China were formed (Wan, 1994). Gondwana Research, V. 4, No. 4, 2001
RODINIA, GONDWANA AND ASIA
The Pacific plate began to subduct to the eastern part of Asian continent by about 30 Ma (Uyeda, 1977; Sen0 and Maruyama, 1984; Maruyama and Seno, 1986). Westward compression and N-S extension occurred in the eastern China continent in the Middle Eocene - Oligocene ( 5 2 - 23.3 Ma, North Sinian tectonic stage). This led to the formation of three mountain ranges with east-west orientation (recent Yinshan-Yanshan, Qinling-Dabie and Nanling mountains began to form) and four original drainage basins. It also marks the main stage of formation of oil and gas in China (Wan, 1994, 1995). The weather of eastern part in China continent since that time was controlled by the Pacific Ocean. The Himalayan Mountains, Tibet-Qinghai plateau, Yangtze and Yellow Rivers all formed in the Himalayan tectonic stage (23.3 - 0.73 Ma, Miocene - Early Pleistocene; Huang and Chen, 1987; Wan, 1994, 1995). Since this time the weather of northwest area of China became very dry, leading to the development of widespread dry regions. The Neotectonic stage is marked by the Middle Pleistocene to Recent, when the migration of oil and gas, distribution of ground water in fractures, earthquakes and other geological hazards occurred (Wan, 1984, 1994). The fractures and faults, nearly paralleled to recent orientation with maximum principal compressive stress, changed to the high permeability zones, permitting easy flow of the underground water and oil and gas. While serving as pathways for other resources, they were also instrumental in triggering natural hazards.
References Huang Jiqing and Chen Bingwei (1987) Evolution of the Tethys Sea in China and its surrounding areas (in Chinese). Geological Publishing House, Beijing, pp. 1-78.
813
Lee, C.Y. (1950) On the Sichuanian movement. Bull. Geol. SOC.China, V. 30, pp. 1-8. Lee, J.S. (1929) Some characteristic structural types in eastern Asia and their bearing upon the problem of continental movement. Geol. Mag., v. 66, pp. 358-375. Maruyama, S. and Seno, T. (1986) Orogeny and relative plate motions: example of t h e J a p a n e s e islands. Tectonophys., v. 1 2 7 , pp. 305-329. Metcalfe, I. (1995) Gondwana dispersion and Asian accretion. Proceedings of the IGCP Symposium on Geology of SE Asia, Honoi, XI / 1995, J. Geol., Ser. B, No. 5-6, pp. 223-265. Moore, G.W. (1989) Mesozoic and Cenozoic paleogeographic development of the Pacific region. Abstract, 2Sth International Geological Congress, Washington, D.C., USA, v. 2, pp. 455-456. Seno, T. and Maruyama, S. (1984) Paleogeographic reconstruction and origin of the Philippine Sea. Tectonophys., v. 102, pp. 53-84. Uyeda, S. (1977) Some basic problems in the trench - arc - back arc basin system. In: Talwani, M. and Pitman, W.C. (Eds.), Island arcs, Deep sea trenches and back-arc-basin. Amer. Geophys. Union, Washington, D.C., Ewing Ser., v. 1, pp. 1-14. Wan Tianfeng (1984) Recent tectonic stress field, active faults and geothermal fields (hot water type) in China. J. Volcanol. Geotherm. Res., v. 22, pp. 287-300. Wan Tianfeng and Zhu Hong (1989) Tectonic stress field of CretaceousEarly Eocene in China. Acta Geologica Sinica, v. 2, pp. 227-239. Wan Tianfeng and Zhu Hong (1991) Tectonic events of Late ProterozoicTriassic in South China. J. South East Asian Earth Sci., v. 6, pp. 147-157. Wan Tianfeng (1994) Intraplate deformation, tectonic stress field and their application for Eastern China in Meso-Cenozoic. Press of China University of Geosciences, Wuhan, pp. 1-156. Wan Tianfeng (1995) On tectonogeomorphology of China. J. China University of Geosci., v. 6, pp. 64-70. Wan Tianfeng (1997) On the accretion of Eastern Asian continental blocks since Triassic. J. China University of Geosci., v. 8, pp. 114-120. Weng Wenhao (1927) Crustal movement and igneous activities in eastern China since Mesozoic time. Bull. Geol. SOC. China, v. 6, pp. 9-36.
Neoproterozoic Rifting History of South China Jian Wang and Chuang-Long Mou Southwestern Region, China Geological Survey, Chengdu 610082, China The integration of sedimentological, sequence stratigraphic and tectonic-stratigraphic data indicates that the Neoproterozoic South China Basins are characteristic of rifting and that their formation and evolution are closely related to the breakup of the supercontinent Rodinia. The basins can be divided into three provinces: southeastern Yangtze province, Kangdian province along the western margin of the Yangtze area and Cathaysian province and further subdivided into five subprovinces and eleven microprovinces on the basis of tectonic settings, sedimentary facies and palaeogeography, and outcrop sequence stratigraphy. Four genetic facies associations and two environmental facies associations which correspond to continental rifting events may also be recognized. The former include: (1) continental volcanic eruptive, ( 2 ) submarine volcanic eruptive, ( 3 ) tillite and (4) eustatic event deposits. The latter comprise: (1) continental and ( 2 ) marine environmental facies association. Gondwana Research, V. 4, No. 4,2001
The palaeogeographic evolution in the South China Basins has undergone four important stages. (1) the beginning of the early Neoproterozoic, i.e., the deposition of the Baizhu Formation and its equivalents Shiqiaopu and Luojiamen Formations, ( 2 ) The beginning of the middle Neoproterozoic, i.e. the deposition of the Sanmenjie Formation and its equivalents Yejia and Shangshu Formations, (3) The end of the middle Neoproterozoic, i.e. the deposition of the Chang’an Formation and its equivalents Changtan and Gucheng Formations and (4) The Late Neoproterozoic, i.e., the deposition of the Nantuo, Doushantuo and Dengying Formations. Four sequence sets have been identified in the Neoproterozoic successions in South China (Wang and Li, 2001), which correspond to continental rifting events. The basal boundary of Sequence set 1 represents the ‘Jinning-Sibao’ orogenic unconformity. Sequence set 2 is well developed throughout the South China Basins. This sequence set is built up of the