Studies suggest that at least four stages of regional-scale tectonic and magmatic events have taken place in the South China block,namely,geodynamic processes of Neoproterozoic and Late Mesozoic active continental margins,Early Paleozoic and Early Mesozoic intracontinental orogenies.The Cathaysia block was a pre-Nanhua basement consisting mainly of Neoproterozoic rocks instead of a stable old land.It experienced a complex evolution from assembly through break-up to re-assembly.The intracontinental shortening during Silurian led to the stabilization of the united South China continent.The entire South China Block was under a shore-shallow sea-slope setting,with no translithospheric fault,no regional-scale volcanism and mantle-derived magmatism in the period from Sinian to Jurassic,during which polyphase tectonic and magmatic events occurred in the united South China lithosphere.It evolved into a part of the Late Mesozoic Western Pacific active continental margin after the Early-Middle Jurassic transformation from Tethysian to Pacific tectonic regimes.The South China lithosphere experienced polyphase continental growth due to the dominant lateral accretion of block assembly accompanied by vertical growth of magma up-swarming.During the Cretaceous,the South China basin and range tectonics occurred in the western shore of the Pacific Ocean due to strong intracontinental extension caused by the northwestward subduction of the Pacific Ocean.Long-term intraplate tectonism and polystage granitic magmatism provided South China with a favorable condition of metallization,forming various large-size ore deposits and resources.Neoproterozoic Nanhua Period and Early Cretaceous were two dominant stages of metallization,with various types of ore deposits being chiefly formed in the Early Cretaceous period.

An analysis of principal features of tectonic evolution in South China Block

Using data from more than 2000 seismic stations from multiple networks arrayed throughout China (CEArray, China Array, NECESS, PASSCAL, GSN) and surrounding regions (Korean Seismic Network, F-Net, KNET), we perform ambient noise Rayleigh wave tomography across the entire region and earthquake tomography across parts of South China and Northeast China. We produce isotropic Rayleigh wave group and phase speed maps with uncertainty estimates from 8 to 50s period across the entire region of study, and extend them to 70s period where earthquake tomography is performed. Maps of azimuthal anisotropy are estimated simultaneously to minimize anisotropic bias in the isotropic maps, but are not discussed here. The 3D model is produced using a Bayesian Monte Carlo formalism covering all of China, extending eastwards through the Korean Peninsula, into the marginal seas, to Japan. We define the final model as the mean and standard deviation of the posterior distribution at each location on a 0.5° × 0.5° grid from the surface to 150km depth. Surface wave dispersion data do not strongly constrain internal interfaces, but shear wave speeds between the discontinuities in the crystalline crust and uppermost mantle are well determined. We design the resulting model as a reference model, which is intended to be useful to other researchers as a starting model, to predict seismic wave fields and observables and to predict other types of data (e.g. topography, gravity). The model and the data on which it is based are available for download. In addition, the model displays a great variety and considerable richness of geological and tectonic features in the crust and in the uppermost mantle deserving of further focus and continued interpretation.

/pdf/a-seismic-reference-model-for-the-crust-and-uppermost-mantle-2az46tsgwd.pdf

A seismic reference model for the crust and uppermost mantle beneath China from surface wave dispersion

Two crustal low-velocity channels beneath SE Tibet revealed by joint inversion of Rayleigh wave dispersion and receiver functions

To better understand the subsurface behavior of subducting slabs and their relation to the tectonic evolution of the overriding plate, we conduct a full waveform inversion on a large data set to determine a high-resolution seismic model, FWEA18 (Full Waveform inversion of East Asia in 2018), of the upper mantle beneath eastern Asia. FWEA18 reveals sharper, more intense high-velocity slabs in the upper mantle under the southern Kuril, Japan, and Ryukyu arcs, than previous studies have found. The subducting Pacific plate is imaged as a roughly 100 km thick high-velocity slab to near 550 km depth indicating relatively little deformation. Stagnation near 600 km depth is observed over horizontal distances of 600 km or less. The Pacific plate we image accounts for roughly 25 Myr of subduction with older slab likely located in the lower mantle. The Philippine plate, subducting beneath the Ryukyu Islands, has a clear termination at about 450 km depth. This may indicate a tearing event in the past or that less Philippine Sea plate has subducted than previously thought. We found a double-layer high-velocity anomaly above and below 660 km under the Yellow Sea and eastern coast of North China. This may correspond to parts of the Philippine Sea plate that detached in the past and Pacific plate that have intersected at depth or a complicated behavior of the Pacific plate at that depth. Slow cylindrical anomalies cross the entire upper mantle are imaged beneath major Holocene volcanoes, which are likely upwellings associated with the edges of deep slabs that are entering the lower mantle.

Seismic Structure of the Upper Mantle Beneath Eastern Asia From Full Waveform Seismic Tomography

3D imaging of subducting and fragmenting Indian continental lithosphere beneath southern and central Tibet using body-wave finite-frequency tomography

High-resolution lithospheric structure beneath Mainland China from ambient noise and earthquake surface-wave tomography

What happened to the Indian mantle lithosphere (IML) during the Indian–Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least four pieces with different angles and northern limits, shallower and extending further in the west and east sides while steeper in the middle. Intermediate-depth earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for Late Miocene and Quaternary rifting, current crustal deformation, and intermediate-depth earthquakes in the southern and central Tibetan Plateau and suggests that the deformations of the crust and the mantle lithosphere are strongly coupled.

https://www.pnas.org/content/pnas/115/33/8296.full.pdf

Tearing of Indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern Tibet

/pdf/tearing-of-indian-mantle-lithosphere-from-high-resolution-4peiusnyti.pdf

Tearing of indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern tibet

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018GL077486

Jiangtao Li

Papers

High-resolution lithospheric structure beneath Mainland China from ambient noise and earthquake surface-wave tomography

Tearing of Indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern Tibet

Tearing of indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern tibet

Joint Inversion for Lithospheric Structures: Implications for the Growth and Deformation in Northeastern Tibetan Plateau

A Generalized H-κ Method With Harmonic Corrections on Ps and Its Crustal Multiples in Receiver Functions