Cratonization is a key geological process to form stable continental masses with a considerable scale.The Precambrian global cratonization and formation of supercratons in the world is an unrepeated event in the histo...Cratonization is a key geological process to form stable continental masses with a considerable scale.The Precambrian global cratonization and formation of supercratons in the world is an unrepeated event in the history of the Earth's formation and evolution.Mainly based on study of early Precambrian geology in Eastern Hebei Region and combining other Archean regions in the North China Craton (NCC),the author proposes a two-stage cratonization model of the NCC.The first stage took place at the end of Neoarchean of ～2.5 Ga (boundary time between Archean and Proterozoic),when several micro-blocks were amalgamated together with amphibolite-granulite facies metamorphism and intrusion of crustal-melting granites to form the present-scale NCC.The second cratonization event is cratonic reworking,corresponding to rifting-subduction-collision at 2.3-1.97 Ga and subsequent extension-uplifting related to upwelling mantle at 1.97-1.82 Ga,which could be linked to,respectively,assembly and breaking up of the Columbia Supercontinent.Three main Paleoproterozoic mobile belts in the NCC record that small remnant Neoarchean ocean basins and continental rift basins within the craton were opened and finally closed,and metamorphosed to greenschist-amphibolite facies at ～2.0-1.97 Ga.After that,high-grade granulite facies (HT-HP and HT-UHT) metamorphism with abnormally high heat occurred at 1.97-1.82 Ga.A metamorphism-migmatization event that includes lower crust of the NCC uplifting as a whole,intrusion of mafic dyke swarms,continental rifting and anorogenic magmatic action took place in 1.82-1.65 Ga,marking that the second cratonization of the NCC was finally accomplished and started to evolve to a period of stable continent (platform).展开更多
华北克拉通发育三条古元古代构造带,包括：东部陆块内部的胶-辽-吉带（Jiao-Liao-Ji belt）、西部陆块内部的孔兹岩带（Khondalite belt）以及两个陆块之间的中部造山带（Trans-North China Orogen）。通过二十多年的深入研究,在区域构...华北克拉通发育三条古元古代构造带,包括：东部陆块内部的胶-辽-吉带（Jiao-Liao-Ji belt）、西部陆块内部的孔兹岩带（Khondalite belt）以及两个陆块之间的中部造山带（Trans-North China Orogen）。通过二十多年的深入研究,在区域构造、变质地质、岩浆作用、地球化学、同位素年代学以及地球物理等方面积累了大量资料,并取得了一系列重要的科学进展。其中,胶-辽-吉带是华北克拉通最具代表性的一条古元古代造山/活动带,它不仅接受了古元古代巨量的陆壳物质沉积,而且经历了十分复杂的构造演化过程,并经受了多期岩浆-变质事件的改造。胶-辽-吉造山/活动带的物质组成最为丰富,以大面积分布的巨量（火山）沉积岩系为特征,在中国境内包括吉南地区的集安群和老岭群、辽东南地区的南辽河和北辽河群、胶北地区的荆山群和粉子山群,向南西则有可能穿越郯庐断裂延伸至徐州-蚌埠一带的五河群,总体呈NE向展布,延伸规模长约1000km。从巨量沉积岩系的岩石组合和空间分布特征来看,荆山群与南辽河群、集安群可以对比,而粉子山群则与北辽河群、老岭群相当。然而,由于多期/多阶段强烈构造变形作用的影响,原来各群、组中地层的上下层位及接触关系已完全破坏,目前均已呈规模不一的构造岩片形式叠置在一起,彼此之间呈断层或韧性剪切带接触。巨量变沉积岩系的源区物质主要来源于造山/活动带内古元古代花岗质岩石和两侧古老陆块的变质基底,原岩形成时代为1.95～2.15Ga左右。以往研究表明,胶-辽-吉造山/活动带变质作用的强度十分不均匀,（中-高压）麻粒岩相变质只局限于胶北的荆山群及相关岩石,而粉子山群以及辽东南的南、北辽河群和吉南的集安群、老岭群只经历了角闪岩相变质,局部甚至只达到绿片岩相变质。粉子山群、北辽河群和老岭群变展开更多
基金supported by National Natural Science Foundation of China(Grant Nos.41030316,90714003)Chinese Academy of Sciences(Grant No.KZCX2-YW-Q04-04)
文摘Cratonization is a key geological process to form stable continental masses with a considerable scale.The Precambrian global cratonization and formation of supercratons in the world is an unrepeated event in the history of the Earth's formation and evolution.Mainly based on study of early Precambrian geology in Eastern Hebei Region and combining other Archean regions in the North China Craton (NCC),the author proposes a two-stage cratonization model of the NCC.The first stage took place at the end of Neoarchean of ～2.5 Ga (boundary time between Archean and Proterozoic),when several micro-blocks were amalgamated together with amphibolite-granulite facies metamorphism and intrusion of crustal-melting granites to form the present-scale NCC.The second cratonization event is cratonic reworking,corresponding to rifting-subduction-collision at 2.3-1.97 Ga and subsequent extension-uplifting related to upwelling mantle at 1.97-1.82 Ga,which could be linked to,respectively,assembly and breaking up of the Columbia Supercontinent.Three main Paleoproterozoic mobile belts in the NCC record that small remnant Neoarchean ocean basins and continental rift basins within the craton were opened and finally closed,and metamorphosed to greenschist-amphibolite facies at ～2.0-1.97 Ga.After that,high-grade granulite facies (HT-HP and HT-UHT) metamorphism with abnormally high heat occurred at 1.97-1.82 Ga.A metamorphism-migmatization event that includes lower crust of the NCC uplifting as a whole,intrusion of mafic dyke swarms,continental rifting and anorogenic magmatic action took place in 1.82-1.65 Ga,marking that the second cratonization of the NCC was finally accomplished and started to evolve to a period of stable continent (platform).
文摘华北克拉通发育三条古元古代构造带,包括：东部陆块内部的胶-辽-吉带（Jiao-Liao-Ji belt）、西部陆块内部的孔兹岩带（Khondalite belt）以及两个陆块之间的中部造山带（Trans-North China Orogen）。通过二十多年的深入研究,在区域构造、变质地质、岩浆作用、地球化学、同位素年代学以及地球物理等方面积累了大量资料,并取得了一系列重要的科学进展。其中,胶-辽-吉带是华北克拉通最具代表性的一条古元古代造山/活动带,它不仅接受了古元古代巨量的陆壳物质沉积,而且经历了十分复杂的构造演化过程,并经受了多期岩浆-变质事件的改造。胶-辽-吉造山/活动带的物质组成最为丰富,以大面积分布的巨量（火山）沉积岩系为特征,在中国境内包括吉南地区的集安群和老岭群、辽东南地区的南辽河和北辽河群、胶北地区的荆山群和粉子山群,向南西则有可能穿越郯庐断裂延伸至徐州-蚌埠一带的五河群,总体呈NE向展布,延伸规模长约1000km。从巨量沉积岩系的岩石组合和空间分布特征来看,荆山群与南辽河群、集安群可以对比,而粉子山群则与北辽河群、老岭群相当。然而,由于多期/多阶段强烈构造变形作用的影响,原来各群、组中地层的上下层位及接触关系已完全破坏,目前均已呈规模不一的构造岩片形式叠置在一起,彼此之间呈断层或韧性剪切带接触。巨量变沉积岩系的源区物质主要来源于造山/活动带内古元古代花岗质岩石和两侧古老陆块的变质基底,原岩形成时代为1.95～2.15Ga左右。以往研究表明,胶-辽-吉造山/活动带变质作用的强度十分不均匀,（中-高压）麻粒岩相变质只局限于胶北的荆山群及相关岩石,而粉子山群以及辽东南的南、北辽河群和吉南的集安群、老岭群只经历了角闪岩相变质,局部甚至只达到绿片岩相变质。粉子山群、北辽河群和老岭群变
