Upper Crustal Velocity Structure of Jiaodong Gold Province from Ambient Noise Double Beamforming Tomography

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Abstract The Jiaodong gold deposits are the largest gold mining base in China, with a rare mineralization scale globally. Their formation differs from existing metallogenic models and may represent a unique type of gold deposit that has not yet been fully and systematically defined. Ore-controlling structures are key factors controlling fluid migration and precipitation, and their study is crucial for understanding metallogenic law and guiding deep exploration. Based on data from a linear short-period dense array spanning the major tectonic units and ore clusters in Jiaodong, this study employs double beamforming tomography to obtain a high-resolution S-wave velocity structure within the upper 8 km of the crust in the region, systematically revealing the major ore-controlling structures and the shallow architecture of the boundary between the North China craton (NCC) and the Yangtze craton (YC). The results show that the Jiaoxibei ore cluster is primarily controlled by a series of low-angle detachment faults, such as the Sanshandao, Jiaojia, Zhaoping, and Qixia faults, which exhibit distinct listric low-velocity anomalies. In contrast, the Muping ore cluster is controlled by steeply dipping faults, such as the Muru fault, which show near-vertical low-velocity anomalies. Significant differences exist in the crustal structure across the Wulian–Yantai fault zone. The eastern YC shows signs of subduction beneath the western NCC, suggesting that this fault zone may be the northern boundary of the collisional orogenic belt between the NCC and YC. Double beamforming tomography effectively enhances weak, but coherent signals and clearly delineates the key structures within the major ore clusters, providing important seismological evidence for understanding the metallogenic process and mechanism of the Jiaodong gold deposits.

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