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Reviewing subduction initiation and the origin of plate tectonics:What do we learn from present-day Earth?

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Earth and Planetary Physics 2021年第2期5卷 123-140页

作者： Gang Lu Liang Zhao Ling Chen Bo Wan FuYuan Wu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The theory of plate tectonics came together in the 1960s,achieving wide acceptance after *** then it has been the most successful framework for investigations of Earth’s *** of the oceanic lithosphere,as the engine that drives plate tectonics,has played a key role in the ***,one of the biggest unanswered questions in Earth science is how the first subduction was initiated,and hence how plate tectonics *** main challenge is how the strong lithosphere could break and bend if plate tectonics-related weakness and slab-pull force were both *** this work we review state-of-the-art subduction initiation(SI)models with a focus on their prerequisites and related driving *** note that the plume-lithosphere-interaction and mantleconvection models do not rely on the operation of existing plate tectonics and thus may be capable of explaining the first *** of plate-driving mechanisms reveals that mantle drag may be the missing driving force for surface plates,capable of triggering initiation of the first *** propose a composite driving mechanism,suggesting that plate tectonics may be driven by both subducting slabs and convection currents in the *** also discuss and try to answer the following question:Why has plate tectonics been observed only on Earth?

关键词： subduction initiation plate tectonics mantle convection driving force mantle drag

Characterization of subduction initiation

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Journal of Oceanology and Limnology 2023年第1期41卷 72-74页

作者： Weidong SUN Lipeng ZHANG Center of Deep Sea Research Institute of OceanologyCenter for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Deep-Sea Multidisciplinary Research Center Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China School of Marine Sciences University of Chinese Academy of SciencesBeing 100049China

Compression is required for all kinds of subduction initiations,which may cause either subsidence or uplift,depending on the ages of the oceanic *** initiations associated with the old oceanic crust tend to amplify pr... 详细信息

关键词： subduction initiation induced and spontaneous west Pacific plate tectonics

Tectono-magmatic evolution of Tethyan oceanic lithosphere in supra subduction zone fore arc regime:Geochemical fingerprints from crust-mantle sections of Naga Hills Ophiolite

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Geoscience Frontiers 2021年第3期12卷 19-41页

作者： Anisha Verencar Abhishek Saha Sohini Ganguly Manikyamba C. CSIR-National Institute of Oceanography Dona PaulaGoa 403004India School of Earth Ocean and Atmospheric SciencesGoa UniversityTaleigão PlateauGoa 403206India CSIR-National Geophysical Research Institute Uppal RoadHyderabad 500007India

The Naga Hills Ophiolite(NHO)belt in the Indo-Myanmar range(IMR)represents a segment of Tethyan oceanic crust and upper mantle that was involved in an eastward convergence and collision of the Indian Plate with the Burmese Plate during the Late ***,we present a detailed petrological and geochemical account for the mantle and crustal sections of NHO,northeastern India to address(i)the mantle processes and tectonic regimes involved in their genesis and(ii)their coherence in terms of the thermo-tectonic evolution of Tethyan oceanic crust and upper *** NHO suite comprises well preserved crustal and mantle sections discretely exposed at Moki,Ziphu,Molen,Washelo and Lacham *** ultramafic-mafic lithologies of NHO are mineralogically composed of variable proportions of olivine,orthopyroxene,clinopyroxene and *** primary igneous textures for the mantle peridotites have been overprinted by extensive serpentinisation whereas the crustal section rocks reflect crystal cumulation in a magma *** normalised REE profiles for the cumulate peridotite-olivine gabbro-gabbro assemblage constituting the crustal section of NHO show flat to depleted LREE patterns consistent with their generation from depleted MORB-type precursor melt in an extensional tectonic setting,while the mantle peridotites depict U-shaped REE patterns marked by relative enrichment of LREE and HREE over *** features collectively imply a dual role of depleted MORB-type and enriched arc-type mantle components for their genesis with imprints of melt-rock and fluid-rock ***,studied lithologies from NHO correspond to a boninitic to slab-proximal Island Arc Tholeiite affinity thereby conforming to an intraoceanic supra subduction zone(SSZ)fore-arc regime coherent with the subduction initiation *** geochemical attributes for the crustal and mantle sections of NHO as mirrored by Zr/Hf,Zr/Sm,Nb/Ta,Zr/Nb,Nb/U,Ba/Nb,Ba/Th,Ba/La and Nd/

关键词： Tethyan Ocean Naga Hills Ophiolite Suprasubduction Zone subduction initiation Fore arc extension Mantle refertilisation

Cretaceous Meteorite Impact-Induced Initial subduction:Records of highly Siderophile Element Abundances and Re-Os Isotopes in Ophiolites

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Journal of Earth Science 2022年第6期33卷 1526-1534页

作者： Benxun Su Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China University of Chinese Academy of Sciences Beijing100049China

Compiled global ophiolite data reveal that Cretaceous ophiolites exhibit broaden variations in 187Re/188Os and ^(187)Os/^(188)Os values,increases in Re concentrations and thus Re/Os ratios in all peridotites and chromitites,and additional increased PPGE/IPGE(Pd-subgroup platinum-group element(PGE)/Ir-subgroup PGE)ratios in chromitites and dunites relative to pre-Cretaceous *** compositional changes in Cretaceous ophiolites,which mostly formed in subduction initiation settings,cannot be attributed solely to involvement of subducting or previously subducted crustal ***,the author proposes a Cretaceous meteorite impact model that led to impact-induced disruption of oceanic lithosphere,asthenosphere upwelling,subduction initiation at edges of laterally spreading ***-pressure and high-temperature conditions during the impacts caused melting of the meteorites and the ambient crustal and mantle rocks,producing hybrid melts containing partially un-melted *** materials contributed to the elevated ^(187)Os/^(188)Os values,Re and Re/Os ratios,whereas the undifferentiated meteorite accounted for the increases in the PPGE/IPGE and decreased ^(187)Os/^(188)Os *** pressure and super-reduced phases were likely generated by this process and were subsequently transported into the newly formed mantle peridotites and chromitites of future *** remaining meteoritic and lithospheric fragments most likely sank deeper and were distributed widely in the convecting mantle to produce the observed global compositional heterogeneities.

关键词： Re-Os isotopes ophiolites PGE meteorites subduction initiation oceanic lithosphere

Evolution and final closure of the Mongol-Okhotsk Ocean

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Science China Earth Sciences 2023年第11期66卷 2497-2513页

作者： Pan ZHAO Bei XU Yan CHEN State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Hebei Key Laboratory of Strategic Critical Mineral Resources Hebei GEO UniversityShijiazhuang 050031China Universitéd’Orléans CNRSBRGMISTOUMR 7327Orléans F-45071France

Mongol-Okhotsk Orogenic Belt is the last main orogen that constructs modern tectonic framework of northeastern Asia. It has recorded the long-term evolution of the Mongol-Okhotsk Ocean(MOO) from its Early Paleozoic initial opening,through the Late Paleozoic-Early Mesozoic subduction, to its Mesozoic final closure, leading to the amalgamation of the Siberian Craton(SIB) and North China-Amuria Block(NCC-AMB). Opening of the MOO can be traced to the early stage of the Early Paleozoic. Northward subduction of the Mongol-Okhotsk oceanic slab beneath the southern margin of the SIB initiated in the Silurian, whereas the southward subduction beneath the northern margin of the NCC-AMB started in the Late Devonian. The bidirectional subduction of the Mongol-Okhotsk oceanic slab resulted in pulse arc magmatism, with three main peaks in the earliest Carboniferous, Late Permian, and Late Triassic-Early Jurassic. In the Late Triassic, the collision between the AMB and Western Mongolian Blocks led to the bending of the Western Mongolian Blocks, which caused the initial closure of the MOO in its western segment. Due to the clockwise rotation of the SIB and counterclockwise rotation of the NCC-AMB, the MOO showed a scissor-like closure from west to east. The final closure of the MOO occurred in the Middle-Late Jurassic, which also resulted in the formation of the Mongol Orocline. Since then, the amalgamation of blocks in northeastern Asia has finished, and the northeastern Asian continent went into the intraplate evolutional stage.

关键词： Northeastern Asia Mongol-Okhotsk Ocean Paleozoic-Mesozoic subduction initiation Scissor-like closure

Key geodynamic processes and driving forces of Tethyan evolution

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Science China Earth Sciences 2023年第12期66卷 2666-2685页

作者： Zhong-Hai LI Fengyuan CUI Shuting YANG Xinyi ZHONG Key Laboratory of Computational Geodynamics College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China

Tethys tectonic system has experienced a long-term evolution history,including multiple Wilson cycles;thus,it is an ideal target for analyzing plate tectonics and *** evolution is typically characterized by a series of continental blocks that separated from the Gondwana in the Southern Hemisphere,drifted northward,and collided and accreted with Laurasia in the Northern *** this process,the successive opening and closing of multistage Tethys oceans(e.g.,Proto-Tethys,Paleo-Tethys,and Neo-Tethys)are considered core parts of the Tethyan ***,focusing on the life cycle of an oceanic plate,four key geodynamic processes during the Tethyan evolution,namely,continental margin breakup,subduction initiation(SI),Mid-Ocean Ridge(MOR)subduction,and continental collision,were highlighted and dynamically analyzed to gather the following insights.(1)Breakup of the narrow continental margin terranes from the northern Gondwana is probably controlled by plate subduction,particularly the subduction-induced far-field *** breakup of the Indian continent and the subsequent spreading of the Indian Ocean can be attributed to the interactions between multiple mantle plumes and slab drag-induced far-field stretching.(2)Continental margin terrane collision-induced subduction transference/jump is a key factor in progressive Tethyan evolution,which is driven by the combined forces of collision-induced reverse push,far-field ridge push,and mantle flow ***,lithospheric weakening plays an important role in the occurrence of SI.(3)MOR subduction is generally accompanied by slab *** case of the considerably reduced or temporary absence of slab pull,mantle flow traction may contribute to the progression of plate *** subduction can dynamically influence the overriding and downgoing plates by producing important and diagnostic geological records.(4)The large gravitational potential energy of the Tibetan Plateau indicat

关键词： Continental margin breakup subduction initiation Mid-Ocean Ridge subduction Continental collision Tethys geodynamics

New perspectives on deep carbon cycling

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Science China Earth Sciences 2024年第8期67卷 2411-2422页

作者： Weidong SUN Center of Deep Sea Research Key Laboratory of Ocean Observation and ForecastingInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Laoshan Laboratory Qingdao 266237China University of Chinese Academy of Sciences Beijing 100049China

The proto-atmosphere serves as a crucial starting point for the carbon *** based on atmospheric data from Mars and Venus suggest that Earth's proto-atmosphere contained>110 bar of CO_(2)and>2.6 bar of *** protoatmosphere had over 1000 bar of water vapor during the magma ocean stage,assuming the proto-ocean had a volume of two oceans of *** this stage both water and carbon dioxide were in a supercritical state at the magma-atmosphere *** serpentinization reactions occurred due to rock-water interaction,producing abundant ***,nitrogen is reduced to ammonia,and carbon dioxide to methane,forming carbonate *** proto-atmosphere dominated by methane,ammonia,and hydrogen formed a significant amount of amino acids through *** process is essential not only to the origin of life,but also to the early carbon-nitrogen cycle on *** the Hadean eon,a large amount of CO_(2)was sequestered as carbonate and organic ***,it mainly entered the deep mantle through mantle overturn or *** the mantle transition zone,carbonate undergoes“Redox freezing”,where carbonate is reduced to diamond through oxidation of ferrous iron in the *** the lower mantle,Fe^(2+)undergoes disproportionation reactions,forming Fe^(3+)and metallic *** these,Fe^(3+)mainly resides in bridgmanite,thereby increasing the oxygen fugacity of the lower mantle,while metallic iron falls to the Earth's *** distribution of carbon in the mantle is crucial for deep carbon *** density curves of diamond and mantle peridotite melt intersect at the bottom of the mantle transition zone(about 660 km).This density crossover leads to the accumulation of diamond during the magma ocean *** materials such as subducting slabs enter the lower mantle,compensatory upwelling of lower mantle material *** enters the upper mantle,decomposes,releasing Fe^(3+)ions and oxidizes diamond

关键词： Carbon cycling Proto-atmosphere Amino acids subduction initiation Passive margin subduction Atmospheric carbon dioxide

Study on the Tectonic Setting for the Ophiolites in Xigaze, Tibet

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Acta Geologica Sinica(English Edition) 2013年第2期87卷 395-425页

作者： BAO Peisheng SU Li WANG Jun ZHAI Qingguo Institute of Geology Chinese Academy of Geological Sciences Institute of Earth Sciences China University of Geosciences

The Xigaze ophiolite is located in the middle section of the Yarlung Zangbo River ophiolite belt and includes a well-preserved sequence section of seven ophiolite blocks. The relatively complete ophiolitic sequence sections are represented by Jiding, Dejixiang, Baigang, and Dazhuqu ophiolites and consist of three-four units. The complete ophiolite sequence in order from the bottom to top consists of mantle peridotite, cumulates, sheeted sill dike swarms, and basic lavas±radiolarian chert. These cumulates are absent in the remaining blocks of Dejixiang and Luqu. The age of radiolaria in the radiolarian chert is Late Jurassic-Cretaceous. The basalt and ultramafic rock of the ophiolite also are overlaid by Tertiary Liuqu conglomerate, which contains numerous pebble components of ophiolite, indicating that the Tethys Ocean began to close at the end of Cretaceous Period. The isotopic data of gabbro, diabase, and albite granite in the Xigaze ophiolite are approximately 126-139 Ma, which indicates that the ophiolite formed in the Early Cretaceous. The K-Ar age of amphibole in garnet amphibolite in the ophiolite melange is 81 Ma, indicating that tectonic ophiolite emplacement occurred at the end of Late Cretaceous. Research in petrology, petrological chemistry, mineralogy, and geochemistry of volcanic rocks and dikes of the Xigaze ophiolite indicate the following characteristics：（1） They are mainly composed of basalt, basaltic andesite, dolerite, and diabase and are characterized by high TiO2 （0.7-1.47%）, low MgO （mostly less than 8%）, and low SiO2 （mostly less than 53%）. （2） The volcanic rocks and dikes of the Xigaze ophiolite show light rare earth element （LREE）-depleted rare earth element （REE） patterns. （3） The spider diagrams of the volcanic rocks and dikes of the Xigaze ophiolite exhibit LILE depletion relative to high-field-strength element （HFSE） patterns with left oblique features. （4） No protogenetic olivine and clinoenstatite was detected. （5） Some dikes show lo

关键词： MORB boninite series rocks forearc extention subduction initiation Xigaze ophiolite

Ophiolites:Identification and tectonic significance in space and time

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Geoscience Frontiers 2023年第6期14卷 380-385页

作者： Kent C.Condie Robert J.Stern Department of Earth&Environmental Science New Mexico Institute of Mining and TechnologySocorroNM 87801USA Geosciences Department University of Texas at DallasRichardsonTX 75080USA

Ophiolites are fragments of oceanic lithosphere that are produced at spreading centers at ocean ridges,back arc basins,or forearcs during subduction initiation,and are key indicators of plate *** it is widely agreed that ophiolites are remnants of oceanic crust and associated depleted mantle preserved in orogens,the recognition of ophiolites and their tectonic significance is still a topic of discussion and *** propose that ophiolites can be recognized in the geologic record by some combination of genetically related pillow basalt,layered gabbro,sheeted dykes,podiform chromite,harzburgite or/and *** igneous rocks have either ocean-ridge basalt or immature oceanic arc basalt chemical *** a scoring system of 1–11 for ophiolite confidence level,scores of8 are considered confident,6–8 probable,andsubduction initiation)tectonic *** ophiolite production requires plate tectonics,subduction must have begun at least locally by 2700 Ma but did not become widespread until after 2000 *** abundance of ophiolites after 900 Ma may reflect better preservation of subduction-related ophiolites,or to an increasing global network of interconnected *** frequency peaks in the geologic record partially reflect geographic regions where ophiolites have been extensively studied rather than monitoring the production rate of ophiolites,but the scarcity of>900 Ma ophiolites is probably real.

关键词： Ophiolite Plate tectonics subduction initiation Forearc Ocean ridge Tectonic setting Supercontinent