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Crustal thickness and composition are closely related to geology and tectonic evolution of the region. Studying the differences in the crustal thickness and composition of the South China Block (SCB) is important to gain a comprehensive understanding of multi-phase amalgamation, breakup, reworking, and regional geodynamic processes. In this study, teleseismic data from 135 high-density portable broadband stations from SinoProbe were processed using Common Conversion Point (CCP) stacking and H-κstacking methods. The Moho depth and P-wave and S-wave velocity ratio (Vp/Vs) were studied. Our results revealed several insights about the tectonic processes in the SCB. First, the crustal structure and Vp/Vsratios of the Cathaysia Block, Jiangnan Orogenic Belt, and Yangtze Block were significantly different. The average depth of the Moho in the Cathaysia Block was approximately 31 km, and the Vp/Vsratios increased from the inland area (1.66) to the coastal area (1.78), indicating the oceanward increase of mafic proportion in the lower crust, which is related to the influence of the Paleo-Pacific Plate westward subduction. Second, the crustal thickness of Jiangnan Orogenic Belt deepens from east ca. 31 to the west ca. 42 km and the Vp/Vsratios varied from 1.75 to 1.64, illustrating a relatively felsic crust, which could have been related to the Mesozoic upper crustal thickening under compression followed by the lower crust removal under the extensional background. Third, the average crustal thickness of the Yangtze Block was 42 km, and the Vp/Vsratios ranged from 1.64 to 1.84, presenting a positive correlation between the Moho depth and the Vp/Vsratio, which is explained by the relatively thick mafic lower crust. Based on the variations in the crustal structure and Vp/Vsratios of the profile, we inferred that the central part of the Jiangnan Orogenic Belt was bounded by the Jiangshan-Shaoxing-Hengyang in the east and the Jiujiang-Shitai-Jishou in the west. The small-scale Moho depth undulations at the intersection of the Cathaysia Block and the Jiangnan Orogenic Belt could be related to the Mesozoic compression-extension geodynamic transformation.

The Middle and Lower Reaches of the Yangtze River metallogenic belt (MLYMB) is one of the most important Fe‐Cu polymetallic belts in China. However, the mechanism and deep geodynamical process for the formation of this belt are still controversial. Here, we obtain the crustal and the uppermost mantle structures using ambient noise data from a dense seismic profile. A low velocity zone is revealed beneath the Moho of MLYMB, interpreted as the source of the deep mineralization materials. In addition, a low velocity layer (LVL) and a high velocity layer (HVL) are observed in the crust of the southern segment of the profile. The LVL is interpreted as a tectonic detachment layer between the upper and the lower crust, and the HVL is interpreted as the aggregation zone for mineralizing melts or crystallized magma chambers. Based on the observed velocity features, we propose a three‐stage model for the formation of ore deposits in MLYMB. Our model suggests that an upwelling of asthenosphere triggered by the delamination of a previously thickened lithosphere leads to the partial melting of upper mantle rocks, which eventually ponders under the Moho. The magma then infiltrates through the ductile lower crust and reaches a depth of ∼7–13 km, forming a minerals‐enriched magma chamber. Minerals‐rich hot fluids originating from the magma chamber continue to move upward along the pre‐existent faults and the minerals finally precipitate in dense veinlets when reaching shallow depths, forming the ore deposits in and around the MLYMB. The formation of large‐scale mineral deposits is closely related to the lithosphere structure. The Middle and Lower Reaches of the Yangtze River metallogenic belt (MLYMB) is an ideal place to study the mineral system, as it is one of the most important Fe‐Cu polymetallic metallogenic belts in Eastern China and contains more than 200 ore deposits. Yet the mechanism and deep geodynamical process for the formation of this belt are still controversial. In this study, we construct a high‐resolution seismic model of the crust and the uppermost mantle using ambient noise data from a dense seismic profile. Our result reveals velocity features closely related to the metallogenic process in this region. Based on the observed velocity features, we propose a three‐stage model for the formation of the ore deposits in MLYMB, which is of great importance for the development of “mineral system” approaches to the exploration of minerals worldwide. We obtain a fine Vs structure of the crust and uppermost mantle beneath the MLYMBWe observe velocity features closely related to the metallogenic process of MLYMBWe propose a three‐stage metallogenic process for the origin of the MLYMB We obtain a fine Vs structure of the crust and uppermost mantle beneath the MLYMB We observe velocity features closely related to the metallogenic process of MLYMB We propose a three‐stage metallogenic process for the origin of the MLYMB

We apply seismic tomography to 590,213 P‐wave arrival‐time data of 23,486 local earthquakes and 300,051 relative travel‐time residuals of 27,492 teleseismic events to study the 3‐D velocity structure of the crust and upper mantle beneath the entire Philippine Sea Plate (PSP) and its adjacent areas. Our results reveal significant high‐velocity anomalies beneath the Philippine Trench, the Japan‐Izu‐Bonin‐Mariana Trench, and the Nankai Trough, which reflect the subducted Philippine Sea slab, the Pacific slab, and the Shikoku Basin, respectively. On the basis of the tomographic images, we construct morphological models of these slabs. The slab morphologies become complex from the east to west. Taking into account previous results of geochemistry, paleomagnetism and numerical simulations, we deem that the complicated morphologies of the subducted slabs are related to the slab age, subduction rate, collision between different plates, clockwise rotation of the PSP, and retreat rate of trenches. The Philippine Sea Plate (PSP) is almost entirely surrounded by subduction zones. We use P‐wave tomography to study the 3‐D velocity structure of the crust and upper mantle beneath the entire PSP for a better understanding of the slab geometry and subduction dynamics. Our tomographic results reveal obvious high‐velocity (high‐V) anomalies beneath the trenches around the PSP, which reflect the subducting Philippine Sea slab, the Pacific slab, and the Shikoku Basin. We construct morphological models of these slabs according to their high‐V anomalies. These slab exhibit quite different morphologies. Taking into account previous geochemical, paleomagnetic and numerical simulation results, we think that the complex slab morphologies are related to the slab age, subduction rate, collision between different plates, clockwise rotation of the PSP, and retreat rate of oceanic trenches. P‐wave tomography is applied to investigate 3‐D velocity structure down to 800 km depth beneath the entire Philippine Sea PlateThe subducting Pacific and Philippine Sea slabs exhibit quite different morphologiesThe morphological differences are caused by the slab age, subduction history and interactions between slab and surrounding mantle P‐wave tomography is applied to investigate 3‐D velocity structure down to 800 km depth beneath the entire Philippine Sea Plate The subducting Pacific and Philippine Sea slabs exhibit quite different morphologies The morphological differences are caused by the slab age, subduction history and interactions between slab and surrounding mantle

Teleseismic body wave traveltime tomography is used to inverse the three-dimensional seismic velocity structure beneath Shizigou in the western Qaidam basin. The travel time are picked from the continuous observation data on a small seismic array of stations deployed during 2004–2007. The tomographic results obtained indicate that a NW-trending low velocity anomaly just beneath the target region insert northeastwards with a high dip angle. In the north, northeast and east of the low velocity anomaly, some high-velocity anomalies distribute with the same strike and coverage as those of Shizigou anticline.

Massive lithospheric thinning occurred in eastern China and large‐scale magmatism in South China occurred in the Mesozoic. Some geodynamic models have been proposed to explain their mechanisms, but are not consistent with each other. We apply anisotropic tomography to 32,728 P‐wave travel time data of 479 teleseismic events recorded at 225 stations to study the 3‐D anisotropic Vp structure of the upper mantle beneath central‐east China. P‐wave radial anisotropy is investigated for the first time in the study region. Our results show that an obvious low‐velocity zone exists in the asthenosphere under the eastern part of our study region, which represents upwelling thermal flow from the Cathaysia block to the North China block (NCB) according to the results of azimuthal and radial anisotropies. A distinct high‐velocity zone with weak radial anisotropy exists under the middle Yangtze block, which is explained as the stable cratonic root. Two other weak high‐velocity zones appear near or within the mantle transition zone under the middle‐lower Yangtze River and the eastern NCB, which might be detached lithosphere or the stagnant Pacific slab. Combining with previous geological and geochemical results, we consider that both the NCB and the South China block have undergone a common geodynamic process in the Mesozoic due to their similar age trending of igneous rocks, which could be explained by a flat‐slab subduction model and a ridge subduction model. These two models are associated with the paleo‐Pacific plate subduction that might have played a key role in the evolution of eastern China. Anisotropic tomography is applied to study the 3D anisotropic velocity structure under central‐east ChinaMantle flow with low P‐wave velocity upwells and moves from the Cathaysia block to the North China blockThe paleo‐Pacific plate subduction might have prompted the thermal material migration Anisotropic tomography is applied to study the 3D anisotropic velocity structure under central‐east China Mantle flow with low P‐wave velocity upwells and moves from the Cathaysia block to the North China block The paleo‐Pacific plate subduction might have prompted the thermal material migration