TY - JOUR
T1 - Mantle dynamics and Cretaceous magmatism in east-central China
T2 - Insight from teleseismic tomograms
AU - Jiang, Guoming
AU - Zhang, Guibin
AU - Zhao, Dapeng
AU - Lü, Qingtian
AU - Li, Hongyi
AU - Li, Xinfu
N1 - Funding Information:
We are grateful to the Data Management Centre of China National Seismic Network at Institute of Geophysics, China Earthquake Administration (SEISDMC, doi:10.7914/SN/CB), for providing the waveform data. We thank the Editors (Prof. J.P. Avouac and Prof. E. Burov) and two anonymous reviewers for their helpful comments and suggestions. This work was co-supported by the Chinese Ministry of Finance (Grant No. SinoProbe-03 ), the China Geological Survey (Grant No. 1212011220244 ), JSPS (Kiban S-23224012 ), MEXT ( 26106005 ), the Beijing Higher Education Young Elite Teacher Project , the Fundamental Research Fund of Key Laboratory of Geo-detection (China University of Geosciences, Beijing) , and the Fundamental Research Funds for the Central Universities . Most figures are made using the GMT software ( Wessel and Smith, 1998 ).
Publisher Copyright:
© 2015 The Authors.
PY - 2015/11/28
Y1 - 2015/11/28
N2 - Both the rich mineralization in the Lower Yangtze Block (LYB) and the post-collisional mafic rocks in the Dabie Orogen (DBO) are closely related to the Cretaceous magmatism in east-central China. Various geodynamic models have been proposed for explaining the mechanism of the Cretaceous magmatism, but these models are controversial and even contradictory with each other, especially on the mechanism of adakites. A unified geodynamic model is required for explaining the magmatism in east-central China, in particular, the spatial and temporal correlations of magmatic activity in the DBO and that in the LYB. For this purpose, we apply teleseismic tomography to study P-wave velocity structure down to 800 km depth beneath east-central China. A modified multiple-channel cross-correlation method is used to collect 28,805 high-quality P-wave arrival-time data from seismograms of distant earthquakes recorded by permanent seismic stations and our temporary stations in the study region. To remove the influence of crustal heterogeneity on the mantle tomography, we used the CRUST1.0 model to correct the teleseismic relative residuals. Our tomography revealed distinct high-velocity (high-V) anomalies beneath the DBO and two flanks of the LYB, and low-velocity (low-V) anomalies above the high-V zones. Combining our tomographic images with previous geological, geochemical and geophysical results, we infer that these high-V and low-V anomalies reflect the detached lithosphere and upwelling asthenospheric materials, respectively, which are associated with the Late Mesozoic dynamic process and the Cretaceous magmatism. We propose a double-slab subduction model that a ridge subduction yielded the adakitic rocks in the LYB during 150-135 Ma and the subsequent Pacific Plate subduction played a crucial role in not only the formation of igneous rocks in the LYB but also remelting of the subducted South China Block beneath the DBO during 135-101 Ma.
AB - Both the rich mineralization in the Lower Yangtze Block (LYB) and the post-collisional mafic rocks in the Dabie Orogen (DBO) are closely related to the Cretaceous magmatism in east-central China. Various geodynamic models have been proposed for explaining the mechanism of the Cretaceous magmatism, but these models are controversial and even contradictory with each other, especially on the mechanism of adakites. A unified geodynamic model is required for explaining the magmatism in east-central China, in particular, the spatial and temporal correlations of magmatic activity in the DBO and that in the LYB. For this purpose, we apply teleseismic tomography to study P-wave velocity structure down to 800 km depth beneath east-central China. A modified multiple-channel cross-correlation method is used to collect 28,805 high-quality P-wave arrival-time data from seismograms of distant earthquakes recorded by permanent seismic stations and our temporary stations in the study region. To remove the influence of crustal heterogeneity on the mantle tomography, we used the CRUST1.0 model to correct the teleseismic relative residuals. Our tomography revealed distinct high-velocity (high-V) anomalies beneath the DBO and two flanks of the LYB, and low-velocity (low-V) anomalies above the high-V zones. Combining our tomographic images with previous geological, geochemical and geophysical results, we infer that these high-V and low-V anomalies reflect the detached lithosphere and upwelling asthenospheric materials, respectively, which are associated with the Late Mesozoic dynamic process and the Cretaceous magmatism. We propose a double-slab subduction model that a ridge subduction yielded the adakitic rocks in the LYB during 150-135 Ma and the subsequent Pacific Plate subduction played a crucial role in not only the formation of igneous rocks in the LYB but also remelting of the subducted South China Block beneath the DBO during 135-101 Ma.
KW - Dabie Orogen
KW - Lower Yangtze Block
KW - Magmatism
KW - Mantle dynamics
KW - Plate subduction
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U2 - 10.1016/j.tecto.2015.09.019
DO - 10.1016/j.tecto.2015.09.019
M3 - Article
AN - SCOPUS:84946844271
SN - 0040-1951
VL - 664
SP - 256
EP - 268
JO - Tectonophysics
JF - Tectonophysics
ER -