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Cyclical one-way continental rupture-drift in the Tethyan evolution: Subduction-driven plate tectonics

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Science China Earth Sciences 2019年第12期62卷 2005-2016页

作者： Bo WAN Fuyuan WU Ling CHEN Liang ZHAO Xiaofeng LIANG Wenjiao XIAO Rixiang ZHU state key laboratory of lithospheric evolution Institute of Geology and Geophysics Chinese Academy of Sciences

Numerous continents have rifted and drifted away from Gondwana to repeatedly open ocean basins over the past-500 *** Gondwana-derived continents drifted towards and collided with components of the Eurasian continent to successively close the preexisting oceans between the *** tectonics satisfactorily describes the continental drift from Gondwana to Eurasia but does not define the geodynamic mechanism of continuously rifting to collisions of continents in the Tethy an *** reappraisal of geological records of the rift,collision and subduction initiation from the surface and various geophysical observations from depth,we propose that Eurasia-directed subducting oceanic slabs would have driven Tethyan system in the *** Eurasia-directed subduction would have dragged the passive Gondwana margin to rift and drift northwards,giving birth to new oceans since the *** closure of preexisting oceans between the Gondwana-derived continents and Eurasia led to continental collisions,which would have induced the initiation of oceanic subduction in the Tethyan *** episodic switches between collision-subduction-rift repeatedly led to the separation of continental fragments from Gondwana and dragged them to drift towards *** final disappearance of Neo-Tethy s would have induced collision of the Gondwana-derived continents with the Eurasian continent,giving rise to the Cenozoic Alpine-Zagros-Himalayan collisional ***,the Eurasia-directed oceanic subduction would have acted as a’one-way train’that successively transferred the ruptured Gondwana continental fragments in the south,into the terminal in the *** this regard,the engine of this"Tethyan one-way train"is the negative buoyancy of subducting oceanic slabs.

关键词： Tethyan geodynamics Oceanic slab Subduction initiation Continental collision Continental rift

Determining the key conditions for the formation of metamorphic core complexes by geodynamic modeling and insights into the destruction of North China Craton

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Science China Earth Sciences 2016年第9期59卷 1873-1884页

作者： LU Gang ZHAO Liang ZHENG TianYu WANG Kun YANG JianFeng state key laboratory of lithospheric evolution of geology and geophysics Chinese Academy of Sciences

Metamorphic core complex(MCC) is characterized by the exhumation of lower crust over a large-scale detachment fault, providing natural records for tectonic extension. MCCs are widely identified in the North China Craton(NCC), which have been intensively studied on their structural and geological characteristics. Yet, the condition for the formation of MCCs and their link with NCC destruction are still in debate. In this study, we perform numerical simulations to investigate MCC formation under extension, with a focus on the effect of crustal rheologies. Results indicate that three end-member modes of deformation may occur: the metamorphic core complex mode, the detachment fault-uplifting mode and the pure shear mode. Weaker lower crust and stronger upper crust may promote the formation of MCC. In contrast, stronger lower crust(>1.3×1021 Pa s) may prohibit the exhumation of lower crust(detachment fault-uplifting mode), while weaker upper crust(<7.8×1021 Pa s) may fail to develop detachment faults(pure shear mode). Given that cratons typically have a strong crust, we suggest that the lower crust of NCC was weakened prior to extension, which promoted the formation of MCC in a later stage under the back-arc extension.

关键词： Metamorphic core complex Numerical modeling North China Craton Extension

Mesozoic and Cenozoic tectonic evolution of the Longmenshan fault belt

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Science China Earth Sciences 2009年第5期52卷 579-592页

作者： WANG ErChie institute of geology and geophysics State Key Laboratory of Lithospheric Evolution Chinese Academy of Sciences

The giant earthquake (M s=8.0) in Wenchuan on May 12, 2008 was triggered by oblique convergence between the Tibetan Plateau and the South China along the Longmenshan fault belt. The Longmenshan fault belt marks an imp... 详细信息

关键词： Wenchuan earthquake Longmenshan landslide flooding Chengdu Plain

Upper mantle seismic anisotropy beneath a convergent boundary:SKS waveform modeling in central Tibet

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Science China Earth Sciences 2014年第4期57卷 759-776页

作者： ZHAO Liang ZHAO Ming LU Gang state key laboratory of lithospheric evolution Institute of Geology and GeophysicsChinese Academy of Sciences

This study used SKS waveforms from the International Deep Profiling of Tibet and the Himalayas(INDEPTH) III dataset and a new 2D method for modeling seismic waves in anisotropic media to construct an image of anisotropic structures beneath central Tibet.A preferred model revealed three-segment anisotropic structures in the upper mantle beneath the study *** modeling demonstrated that the anisotropy was mainly generated by the lithosphere but not the asthenosphere,and that an anisotropic model with a flatter axis of symmetry provides a more consistent interpretation of the observations than models having steeply dipping symmetry axes.A relatively low velocity zone may underlie or intermingle with the anisotropic structures in the northern portion of the *** tests also indicate that variations in the elastic constants and depth extent of the anisotropy assumed by the calculations do not affect the general conclusions,although trade-offs exist among certain model *** modeling results suggest that the complex seismic structures in central Tibet were associated with underthrusting of the Indian lithosphere beneath the Asian lithosphere;the inferred flat symmetry axis of the anisotropy was likely generated during this collision *** this were not the case,the inherited anisotropy would exhibit a steeply dipping axis of symmetry,parallel to the direction of underthrusting.

关键词： waveform modeling spectral element method upper mantle anisotropy central Tibet

The influence of Tethyan evolution on changes of the Earth's past environment

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Science China Earth Sciences 2023年第12期66卷 2653-2665页

作者： Bo WAN Fuyuan WU Rixiang ZHU state key laboratory of lithospheric evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

Understanding changes in Earth's past can provide valuable insights into prediction of its *** example is the interactions between the internal and external spheres of *** cyclical northward breakup-drift of Gondwana,driven by the opening and closure of Proto-,Paleo-,and Neo-Tethyan oceans,facilitated the transfer of landmasses from the southern to the northern hemisphere,traversing the tropic *** have observed a compelling correlation between episodic increases in landmass area within the tropic regions(those lying at less than 20°latitude)and a subsequent temperature decrease during the three major glacial periods in the last 500 million *** phenomenon can be attributed to low latitude regions receiving more solar energy influx on Earth's surface than high latitude *** addition,an increase of landmass in tropic regions(low latitude)attenuates the net energy absorption by the Earth's surface,consequently impeding the conduction and convection of absorbed energy toward the *** result is a decrease in global surface *** tropic regions,benefiting from abundant sunlight,create an ideal environment for the proliferation of marine plankton *** species are important in the generation of organic-rich *** biological debris is therefore deposited on continental margins when a continent drifts across the tropic *** creates favorable conditions for future hydrocarbon and reservoir *** subduction of organic-rich sediments during the closure of the Tethyan oceans results in the generation of mafic arc magmas with low oxygen *** chemical environment helps the mineralization of reduced-type ore deposits such as tungsten,tin,and ***-driven plate tectonics in the Tethys realm changes the distribution of oceans and landmass,subsequently affecting the balance and distribution of solar energy across Earth's *** changes trigger consequential environmental shif

关键词： Tethyan geodynamics Earth system Change of sea-land distribution Reduced ore deposit Hydrocarbon

Major Advances in the Study of the Precambrian geology and Metallogenesis of the North China Craton:A Review

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Acta Geologica Sinica(English Edition) 2016年第4期90卷 1122-1155页

作者： ZHAO Lei ZHU Xiyan ZHAI Mingguo state key laboratory of lithospheric evolution Institute of Geology and Geophysics Chinese Academy of Science key laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Academy of Sciences

The North China Craton （NCC） is one of the most ancient cratons in the world and records a complex geological evolution since the early Precambrian. In addition to recording major geological events similar to those of other cratons, the NCC also exhibits some unique features such as multi- stage cratonization （late Archaean and Palaeoproterozoic） and long-term rifting during the Meso- Neoproterozoic. The NCC thus provides one of the best examples to address secular changes in geological history and metallogenic epochs in the evolving Earth. We summarize the major geological events and metallogenic systems of the NCC, so that the evolutionary patterns of the NCC can provide a better understanding of the Precambrian NCC and facilitate comparison of the NCC with other ancient continental blocks globally. The NCC experienced three major tectonic cycles during the Precambrian：（1） Neoarchaean crustal growth and stabilization; （2） Palaeoproterozoic rifting-subduction-accretion-collision with imprints of the Great Oxidation Event and （3） Meso-Neoproterozoic multi-stage rifting. A transition from primitive- to modern-style plate tectonics occurred during the early Precambrian to late Proterozoic and is evidenced by the major geological events. Accompanying these major geological events, three major metallogenic systems are identified：（1） the Archaean banded iron formation system; （2） Palaeoproterozoic Cu-Pb-Zn and Mg-B systems and （3） a Mesoproterozoic rare earth element-Fe- Pb-Zn system. The ore-deposit types in each of these metallogenic systems show distinct characteristics and tectonic affinities.

关键词： North China Craton geological events metallogenesis cratonization multi-stage rifting

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

Geochemical characteristics and geological significance of Cretaceous phonotephrite from the Mid-Pacific Mountains

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Science China Earth Sciences 2018年第6期61卷 745-764页

作者： Shuangshuang CHEN Jiaqi LIU key laboratory of Cenozoic geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences state key laboratory of lithospheric evolution Institute of Geology and Geophysics Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences

Systematic analyses were conducted including the petrographic features, major and trace elements, Sr and Nd isotopic compositions, and mineral structure and compositions of whole rocks. Mid-Pacific Mountain volcanic rocks are mainly phonotephrite with a porphyritic texture. Phenocrysts are mainly composed of Ca-rich plagioclase, clinopyroxene and *** volcanic rocks are significantly rich in large-ion lithophile and light rare earth elements, without obvious Eu anomalies(δEu=0.99–1.03), and with relatively enriched^(87) Sr/^(86) Sr(0.703829–0.704313) and^(143) Nd/^(144) Nd isotopic ratios(0.512857–0.512871), suggesting that they have similar but more enriched features than the OIB magmatic source. These volcanic rocks may originate from relatively deep magma source with the existence of spinel-garnet Iherzolites, and have undergone partial melting at a low degree of 1–3%. In addition, The residual Nb-Ta minerals(such as sphene, rutile, perovskite) may remain in the mantle source, and the magma components have undergone metasomatism by carbonate melt/fluid or alkali-rich fluid, causing high contents of incompatible elements and significant loss of Nb, Ta and Ti in these volcanic rocks. There are many similarities between the phonotephrites in the Mid-Pacific Mountain and the volcanic rocks in the Line Islands based on the tectonic settings and the geochemical characteristics. We thus speculate that Site 313 volcanic rocks in the Mid-Pacific Mountain is most likely to be a continuation of the Line Islands.

关键词： Phonotephrite OIB-type mantle source Carbonatite metasomatism Line Islands Mid-Pacific Mountain

Mantle dynamics of the reactivating North China Craton:Constraints from the topographies of the 410-km and 660-km discontinuities

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Science China Earth Sciences 2011年第6期54卷 881-887页

作者： XU WeiWei ZHENG TianYu ZHAO Liang Seismological laboratory State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The topographies of the 410-km and 660-km discontinuities have important implications for mantle *** we present high-resolution seismic imaging of the 410-km and 660-km discontinuities beneath the North China Craton (NCC) employing the receiver function *** anomalies (deeper or shallower than the global average depths) at both discontinuities were detected by introducing a three-dimensional regional velocity *** depressions of the 410-km discontinuity are mostly located in the eastern NCC.A local elevation of the 660-km discontinuity appeared in the northwest of the NCC and a significant depression of the 660-km discontinuity is located in the southeast of the *** dynamic mantle regimes are speculated to explain the formation of the anomalous depth zones in the *** possibility is a complex mantle upwelling linked to edge-derived convection between the stagnant slab and the thick cratonic *** other potential dynamic regime is slab stagnating,sinking,and induced upwelling at the neighboring slab *** regimes hint that the mantle flow was possibly dominated by dynamic interactions among the subducting slab,cratonic root,and ambient mantle beneath the NCC.

关键词： 410-km discontinuity 660-km discontinuity receiver function imaging dynamic mantle regime North China Craton