The Wulian complex occurring in the north- western part of the Sulu orogen consists of metaigneous and metasedimentary rocks at greenschist-facies. Zircon U-Pb dating for three granite intrusions within it yields conc...The Wulian complex occurring in the north- western part of the Sulu orogen consists of metaigneous and metasedimentary rocks at greenschist-facies. Zircon U-Pb dating for three granite intrusions within it yields concor-dant ages of (672±4), (742±9) and (747±14) Ma, respec-tively. These ages indicate that the granites are the Neopro-terozoic intrusions in the northern margin of the Yangtze plate, and correspond to the magmatic complex at Luzhen-guan in the eastern part of the Beihuaiyang belt in the Dabie orogen. They were tectonic slices scraped off from the Yang-tze plate during Triassic subduction and thus belong to a part of the accretionary wedge of the Yangtze plate subduc-tion. The discovery of extensive Neoproterozoic magmatic rocks in the Wulian area suggests that the suture location between the North China and the Yangtze plates lies north of the Wulian complex.展开更多
The Sulu Orogen constitutes the eastern part of the Sulu-Dabie Orogen formed by Triassic collision between the Sino-Korean and Yangtze plates. An HP Slice Ⅰ and two UHP slices Ⅱ and Ⅲ with contrasting subduction an...The Sulu Orogen constitutes the eastern part of the Sulu-Dabie Orogen formed by Triassic collision between the Sino-Korean and Yangtze plates. An HP Slice Ⅰ and two UHP slices Ⅱ and Ⅲ with contrasting subduction and exhumation histories within the Sulu Orogen were postulated. This study presents the metamorphic P-T paths of eclogites from the two UHP belts constructed by petrog- raphy, mineral chemistry and Perple_X P-T pseudosection modeling in the MnC（K）NFMASHO system. Eclogites from Slice Ⅲ mainly consist of omphacite, garnet and quartz, with minor rutile, ilmenite, amphibole and phengite. Eclogites from Slice Ⅱ show a porphyroblastic texture with epidote porphyroblasts and garnet, omphacite, phengite, quartz and rutile in matrix. Pseudosection modeling reveals that eclogites from Slice Ⅱ witness a peak metamorphism of eclogite-facies under conditions of 3.1-3.3 GPa and 660-690 ℃, and a retrograde cooling decompression process. The eclogites from Slice Ⅲ record a heating decompressive P-T path with a peak-P stage of 3.2 GPa and 840℃ and a peak-T stage of 2.4 GPa and 950 ℃, suggesting an apparent granulite-facies metamorphism overprint during exhumation. Both eclogites recorded clockwise P-T paths with peak P-T conditions suggesting a subduction beneath the Sino-Korean Plate to -100-105 km depth. Combined with tectonic scenarios from previous studies, it is concluded that the two UHP crustal slices in the Sulu terrane have a similar geodynamic evolution, but the UHP rocks in Slice Ⅱ exhumed after the eclogitic peak-pressure conditions earlier than that of Slice Ⅲ. The existence of Slice Ⅱ diminished the buoyancy force on Slice Ⅲ, resulting in a granulite-facies overprint on Slice Ⅲ. The Sulu orogenic belt is made up of different crustal slices that underwent different subduction and exhumation histories, rather than a single unit.展开更多
The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events,corresponding to the breaking up of the Rodinia supercontinent.The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northe...The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events,corresponding to the breaking up of the Rodinia supercontinent.The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northern Sulu Orogen are not well-constrained.This study reports zircon U-Pb ages and Hf isotopes of these rocks from the Liansandao area.Three meta-igneous rock samples give similar weighted mean 206 Pb/238 U ages of 744±11,767±12,and 762±15 Ma,respectively,indicating the Neoproterozoic crystallization ages.These rocks formed coevally with the Wulian and Yangkou intrusions that located along the Yantai-Qingdao-Wulian fault zone.The Neoproterozoic ages indicate that the meta-igneous rocks from the Liansandao area have affinity to the Yangtze Block.The three samples haveεHf(t)values of-7.2–-10.5,-6.0–-17.5,and-6.8–-12.0,respectively.These negativeεHf(t)values indicate a primarily crustal source.However,the widely variousεHf(t)values that are higher than the continental crust,suggesting magma mixing between mantle-derived materials and the continental crust or source heterogeneity.Combined with the Hf model ages and geochemical characteristics,the monzodiorite(sample LSD-2)is most likely to be mantle-derived magma then interacted with ancient continental crust,and the granitic protolith(samples LSD-1 and LSD-3)in the Liansandao area might derive from the re-melting of a Paleoproterozoic continental crust at^750 Ma,resulting from the upwelling and underplating of mantle-derived magma formed in an extensional setting due to the break-up of the Rodinia supercontinent.展开更多
基金supported by funds from the Chinese Academy of Sciences(Grant No.KZCX2-107)the National Natural Science Foundation of China(Grant No.40272100).
文摘The Wulian complex occurring in the north- western part of the Sulu orogen consists of metaigneous and metasedimentary rocks at greenschist-facies. Zircon U-Pb dating for three granite intrusions within it yields concor-dant ages of (672±4), (742±9) and (747±14) Ma, respec-tively. These ages indicate that the granites are the Neopro-terozoic intrusions in the northern margin of the Yangtze plate, and correspond to the magmatic complex at Luzhen-guan in the eastern part of the Beihuaiyang belt in the Dabie orogen. They were tectonic slices scraped off from the Yang-tze plate during Triassic subduction and thus belong to a part of the accretionary wedge of the Yangtze plate subduc-tion. The discovery of extensive Neoproterozoic magmatic rocks in the Wulian area suggests that the suture location between the North China and the Yangtze plates lies north of the Wulian complex.
基金funded by the National Key R & D Program of China (No. 2016YFC0600403)the State Scholarship Fund of the China Scholarship Council (CSC) to Yilong Lithe Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (Nos. CUGL170404, CUG160232)
文摘The Sulu Orogen constitutes the eastern part of the Sulu-Dabie Orogen formed by Triassic collision between the Sino-Korean and Yangtze plates. An HP Slice Ⅰ and two UHP slices Ⅱ and Ⅲ with contrasting subduction and exhumation histories within the Sulu Orogen were postulated. This study presents the metamorphic P-T paths of eclogites from the two UHP belts constructed by petrog- raphy, mineral chemistry and Perple_X P-T pseudosection modeling in the MnC（K）NFMASHO system. Eclogites from Slice Ⅲ mainly consist of omphacite, garnet and quartz, with minor rutile, ilmenite, amphibole and phengite. Eclogites from Slice Ⅱ show a porphyroblastic texture with epidote porphyroblasts and garnet, omphacite, phengite, quartz and rutile in matrix. Pseudosection modeling reveals that eclogites from Slice Ⅱ witness a peak metamorphism of eclogite-facies under conditions of 3.1-3.3 GPa and 660-690 ℃, and a retrograde cooling decompression process. The eclogites from Slice Ⅲ record a heating decompressive P-T path with a peak-P stage of 3.2 GPa and 840℃ and a peak-T stage of 2.4 GPa and 950 ℃, suggesting an apparent granulite-facies metamorphism overprint during exhumation. Both eclogites recorded clockwise P-T paths with peak P-T conditions suggesting a subduction beneath the Sino-Korean Plate to -100-105 km depth. Combined with tectonic scenarios from previous studies, it is concluded that the two UHP crustal slices in the Sulu terrane have a similar geodynamic evolution, but the UHP rocks in Slice Ⅱ exhumed after the eclogitic peak-pressure conditions earlier than that of Slice Ⅲ. The existence of Slice Ⅱ diminished the buoyancy force on Slice Ⅲ, resulting in a granulite-facies overprint on Slice Ⅲ. The Sulu orogenic belt is made up of different crustal slices that underwent different subduction and exhumation histories, rather than a single unit.
基金financially supported by the Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology (No. MGQNLM201902)the National Natural Science Foundation of China (Nos. 41472155,41876037)+2 种基金the Scientific and Technological Innovation Project of the China Ocean Mineral Resources R & D Association (No. DY135-N2-1-04)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (No. 2016RCJJ008)the SDUST Research Fund (No. 2015TDJH101).
文摘The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events,corresponding to the breaking up of the Rodinia supercontinent.The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northern Sulu Orogen are not well-constrained.This study reports zircon U-Pb ages and Hf isotopes of these rocks from the Liansandao area.Three meta-igneous rock samples give similar weighted mean 206 Pb/238 U ages of 744±11,767±12,and 762±15 Ma,respectively,indicating the Neoproterozoic crystallization ages.These rocks formed coevally with the Wulian and Yangkou intrusions that located along the Yantai-Qingdao-Wulian fault zone.The Neoproterozoic ages indicate that the meta-igneous rocks from the Liansandao area have affinity to the Yangtze Block.The three samples haveεHf(t)values of-7.2–-10.5,-6.0–-17.5,and-6.8–-12.0,respectively.These negativeεHf(t)values indicate a primarily crustal source.However,the widely variousεHf(t)values that are higher than the continental crust,suggesting magma mixing between mantle-derived materials and the continental crust or source heterogeneity.Combined with the Hf model ages and geochemical characteristics,the monzodiorite(sample LSD-2)is most likely to be mantle-derived magma then interacted with ancient continental crust,and the granitic protolith(samples LSD-1 and LSD-3)in the Liansandao area might derive from the re-melting of a Paleoproterozoic continental crust at^750 Ma,resulting from the upwelling and underplating of mantle-derived magma formed in an extensional setting due to the break-up of the Rodinia supercontinent.
