The metasedimentary Lujiapuzi Formation crops out along the northeastern margin of the North China Craton, close to the Yan-Liao Rift. The age and tectonic setting of the formation, and its relationship with the Yan-L...The metasedimentary Lujiapuzi Formation crops out along the northeastern margin of the North China Craton, close to the Yan-Liao Rift. The age and tectonic setting of the formation, and its relationship with the Yan-Liao Rift are currently unclear. Here we present detrital zircon U-Pb ages, and Hf isotopic and geochemical data for the Lujiapuzi Formation to constrain the timing of deposition, the provenance of the formation, and the regional stratigraphy relationship. Zircon U-Pb dating constrains the timing of deposition of the Lujiapuzi Formation to younger than 1780 Ma, and indicates that most grains were sourced from the Longgang Block and the Paleoproterozoic Liao-Ji Belt. Detailed field investigations and a correlation of the regional stratigraphy reveal that much of the Lujiapuzi Formation is equivalent to the Tuanshanzi Formation in the Yan-Liao Rift; the lower section may represent the earliest sediments deposited within the Fanhe Basin. Based on these results and the findings of previous studies, we suggest that the base of the Changcheng System has an age of 1.80 Ga. Zircon Hf isotopic data indicate that the main period of crustal growth along the northeastern margin of the North China Craton occurred at 3.2–2.5 Ga, with a peak at 2.9–2.7 Ga.展开更多
During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
鲁西地区发育大规模的中元古代基性岩墙群,侵位于早前寒武纪结晶基底内,未变形未变质,以北北西向和近南北向为主,是鲁西前寒武纪最引人注目的一种伸展构造标志。鲁西基性岩墙群属于板内大陆裂谷拉斑玄武岩系列,与板内大陆裂谷活动密切相...鲁西地区发育大规模的中元古代基性岩墙群,侵位于早前寒武纪结晶基底内,未变形未变质,以北北西向和近南北向为主,是鲁西前寒武纪最引人注目的一种伸展构造标志。鲁西基性岩墙群属于板内大陆裂谷拉斑玄武岩系列,与板内大陆裂谷活动密切相关,代表一种非造山岩浆活动。该岩墙群富集大离子亲石元素(L IL E) ,略亏损高场强元素(HFSE) ,比较富集Cr、Ni,明显亏损Th。稀土元素配分模式为轻稀土略富集的右倾曲线。鲁西基性岩墙群的微量元素和稀土元素特征反映源区为略富集的地幔。从时空分布特征、构造特征、岩石化学相关性、岩浆源区和古构造应力场分析,鲁西基性岩墙群与燕辽—中条拗拉槽系有一定的成生联系。展开更多
Baltica was one of continents formed as a result of Rodinia break-up 850-550 Ma. It was separated from Amazonia(?) by the Tornquist Ocean, the opening of which was preceded by Neoproterozoic extension in a network of ...Baltica was one of continents formed as a result of Rodinia break-up 850-550 Ma. It was separated from Amazonia(?) by the Tornquist Ocean, the opening of which was preceded by Neoproterozoic extension in a network of continental rifts. Some of these rifts were subsequently aborted whereas the Tornquist Rift gave rise to splitting of Rodinia and formation of the Tornquist Ocean. The results of 1-D subsidence analysis at the fossil passive margin of Baltica provided insight in the timing and kinematics of continental rifting that led to break-up of Rodinia. Rifting was associated with Neoproterozoic syn-rift subsidence accompanied by deposition of continental coarse-grained sediments and emplacement of continental basalts.Transition from a syn-rift to post-rift phase in the latest Ediacaran to earliest early Cambrian was concomitant with deposition of continental conglomerates and arkoses, laterally passing into mudstones. An extensional scenario of the break-up of Rodinia along the Tornquist Rift is based on the character of tectonic subsidence curves, evolution of syn-rift and post-rift depocenters in time, as well as geochemistry and geochronology of the syn-rift volcanics. It is additionally reinforced by the high-quality deep seismic reflection data from SE Poland, located above the SW edge of the East European Craton. The seismic data allowed for identification of a deeply buried(11-18 km), well-preserved extensional half-graben, developed in the Palaeoproterozoic crystalline basement and filled with a Neoproterozoic syn-rift volcano-sedimentary succession. The results of depth-to-basement study based on integration of seismic and gravity data show the distribution of local NE-SW elongated Neoproterozoic depocenters within the SW slope of the East European Craton. Furthermore,they document the rapid south-eastwards thickness increase of the Neoproterozoic succession towards the NW-SE oriented craton margin. This provides evidence for extensive crustal thinning occurring prior to the break-up of Rodinia and formation of the Tornquist Ocean.展开更多
基金financially supported by the Nature Science Foundation of China (41772214 and 41872203)the 12th Chinese 1000 Young Talents Program, National Nature Science Foundation of China (2016-67, 32020002)+1 种基金the China Postdoctoral Science Foundation Grant (2018M633210)the China Geological Survey (12120113057900)
文摘The metasedimentary Lujiapuzi Formation crops out along the northeastern margin of the North China Craton, close to the Yan-Liao Rift. The age and tectonic setting of the formation, and its relationship with the Yan-Liao Rift are currently unclear. Here we present detrital zircon U-Pb ages, and Hf isotopic and geochemical data for the Lujiapuzi Formation to constrain the timing of deposition, the provenance of the formation, and the regional stratigraphy relationship. Zircon U-Pb dating constrains the timing of deposition of the Lujiapuzi Formation to younger than 1780 Ma, and indicates that most grains were sourced from the Longgang Block and the Paleoproterozoic Liao-Ji Belt. Detailed field investigations and a correlation of the regional stratigraphy reveal that much of the Lujiapuzi Formation is equivalent to the Tuanshanzi Formation in the Yan-Liao Rift; the lower section may represent the earliest sediments deposited within the Fanhe Basin. Based on these results and the findings of previous studies, we suggest that the base of the Changcheng System has an age of 1.80 Ga. Zircon Hf isotopic data indicate that the main period of crustal growth along the northeastern margin of the North China Craton occurred at 3.2–2.5 Ga, with a peak at 2.9–2.7 Ga.
基金supported by the Major State Basic Research Development Program of China (973 Program No: 2012CB416601)+1 种基金the National Natural Science Foundation of China (No: 41322018) projectsthe National High-Level Talents Special Support Plan
文摘During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
文摘鲁西地区发育大规模的中元古代基性岩墙群,侵位于早前寒武纪结晶基底内,未变形未变质,以北北西向和近南北向为主,是鲁西前寒武纪最引人注目的一种伸展构造标志。鲁西基性岩墙群属于板内大陆裂谷拉斑玄武岩系列,与板内大陆裂谷活动密切相关,代表一种非造山岩浆活动。该岩墙群富集大离子亲石元素(L IL E) ,略亏损高场强元素(HFSE) ,比较富集Cr、Ni,明显亏损Th。稀土元素配分模式为轻稀土略富集的右倾曲线。鲁西基性岩墙群的微量元素和稀土元素特征反映源区为略富集的地幔。从时空分布特征、构造特征、岩石化学相关性、岩浆源区和古构造应力场分析,鲁西基性岩墙群与燕辽—中条拗拉槽系有一定的成生联系。
基金supported by the National Science Centre (NCN)(grant No.2012/05/B/ST10/00521)
文摘Baltica was one of continents formed as a result of Rodinia break-up 850-550 Ma. It was separated from Amazonia(?) by the Tornquist Ocean, the opening of which was preceded by Neoproterozoic extension in a network of continental rifts. Some of these rifts were subsequently aborted whereas the Tornquist Rift gave rise to splitting of Rodinia and formation of the Tornquist Ocean. The results of 1-D subsidence analysis at the fossil passive margin of Baltica provided insight in the timing and kinematics of continental rifting that led to break-up of Rodinia. Rifting was associated with Neoproterozoic syn-rift subsidence accompanied by deposition of continental coarse-grained sediments and emplacement of continental basalts.Transition from a syn-rift to post-rift phase in the latest Ediacaran to earliest early Cambrian was concomitant with deposition of continental conglomerates and arkoses, laterally passing into mudstones. An extensional scenario of the break-up of Rodinia along the Tornquist Rift is based on the character of tectonic subsidence curves, evolution of syn-rift and post-rift depocenters in time, as well as geochemistry and geochronology of the syn-rift volcanics. It is additionally reinforced by the high-quality deep seismic reflection data from SE Poland, located above the SW edge of the East European Craton. The seismic data allowed for identification of a deeply buried(11-18 km), well-preserved extensional half-graben, developed in the Palaeoproterozoic crystalline basement and filled with a Neoproterozoic syn-rift volcano-sedimentary succession. The results of depth-to-basement study based on integration of seismic and gravity data show the distribution of local NE-SW elongated Neoproterozoic depocenters within the SW slope of the East European Craton. Furthermore,they document the rapid south-eastwards thickness increase of the Neoproterozoic succession towards the NW-SE oriented craton margin. This provides evidence for extensive crustal thinning occurring prior to the break-up of Rodinia and formation of the Tornquist Ocean.
