Image: https://scx1.b-cdn.net/csz/news/tmb/2023/seismic-waves-tell-lit.jpg” data-src=”https://scx2.b-cdn.net/gfx/news/hires/2023/seismic-waves-tell-lit.jpg” data-sub-html=The South China block’s tectonic setting and magmatic dispersion during the Mesozoic. South China block tectonic and topographical map. Tomography imaging profiles (A-A′, B-B′, C-C′, D-D′, and E-E′) are shown by the blue dashed lines. Major faults (JSF: Jiangshan-Shaoxing fault; TLF: Tanlu fault; ZDF: Zhenghe-Dabu fault) and tectonic units (Yangtze block; Cathaysia block; Triassic Qinling-Dabie orogen; Proterozoic Jiangnan orogen) are delineated by solid red lines. North China block (NCB), Jianghan basin (JHB), and Sichuan basin (SCB). b Mesozoic magmatism in the South China block: a spatial and chronological analysis. Tectonic units and faults share the same names as a. Mafic rocks of varying ages are represented by the filled circles, whereas granitoids and their volcanic analogues are shown by the squares of varying colours. The felsic rocks of the Late Mesozoic are typically found at greater distances from their origin. Nature, Communications, (1983). Its DOI is 10.1038/s41467-023-37855-5. data-src=”https://scx2.b-cdn.net/gfx/news/hires/2023/seismic-waves-tell-lit.jpg” data-sub-html=”https://scx1.b-cdn.net/csz/news/tmb/2023/seismic-waves-tell-lit.jpg”South China block tectonics and Mesozoic magmatic circulation. South China block tectonic and topographical map. Tomography imaging profiles (A-A ′, B-B ′, C-C ′, D-D ′, and E-E ′) are indicated by hurried blue lines. The Yangtze block, the Cathaysia block, the Triassic Qinling-Dabie orogen, and the Proterozoic Jiangnan orogen are all denoted by bold red lines, as are the Jiangshan-Shaoxing fault (JSF), the Tanlu fault (TLF), and the Zhenghe-Dabu fault (ZDF). North China block (NCB), Sichuan basin (SCB), and Jianghan basin (JHB) The South China block’s spatial-temporal magmatism circulation during the Mesozoic. Tectonic system and fault names are identical to those of aAreas of mafic rocks in their various phases are shown by the thick rings, while those of granitoids and their volcanic equivalents are shown by the coloured squares. The felsic rocks of the Late Mesozoic have a greater propensity for development when exposed to the outdoors. Authors’ affiliation: Nature Communications; DOI: 10.1038/s41467-023-37855-5; 2023.
The seismic imaging of lithospheric delamination and its controls on the Mesozoic Magmatic Province in South China were revealed by a group of researchers led by Professor Zhang Haijiang of the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences and Professor Hou Zengqian of the Chinese Academy of Geological Sciences. Nature Communications published the study’s findings.
The researchers used the seismic body wave travel time, surface area wave dispersion information, and receiver function to determine the high-resolution shear wave speed design of the South China lithosphere using the most recent industrialised seismic joint inversion technique. At a depth of fewer than 90 km, they found evidence of high-velocity anomalies in the asthenosphere.
These high-velocity anomalies may be interpreted as blocks of delaminating lithosphere that were warmed by the deep mantle and then drifted back to their original location around 180–170 Ma. The lithosphere improved after massive delamination, which triggered lithosphere thinning and adiabatic asthenosphere upwelling. Because of this, a magmatic province formed beneath South China as the lithosphere grew and the crust above it melted.
Delamination required a lot of water and heat from the convective mantle, which was revealed by geochemical research. The resulting magmatic rocks and metal deposits are characterised by the presence of abundant granitoid and mafic rocks.
knowledge the dynamics of the Paleo-Pacific plate, which caused the vast mineralization in South China during the late Mesozoic, is made much easier with the help of the new knowledge of the development system given by this work. It also contributes novelties to our understanding of the relationship between shallow lava and mineralization, as well as the power of the deep procedure of the lithosphere.
More details:
The Mesozoic Magmatic Province in South China and its management by seismic imaging of lithospheric delamination, Haijiang Zhang et al., Nature Communications (2023). DOI: 10.1038/ s41467-023-37855-5
Provided by the Chinese Academy of Sciences
The Lithospheric Delamination System in South China Is Communicated by Seismic Waves, retrieved from https://phys.org/news/2023-06-seismic-convey-lithospheric-delamination-mechanism.html on June 9, 2023.
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