High-resolution crustal structure and gold mineralization in the southwest Cathaysia block revealed by a dense seismic array
High-resolution crustal structure and gold mineralization in the southwest Cathaysia block revealed by a dense seismic array
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DOI：
10.1016/j.tecto.2021.229012
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发表时间：
2021-10
期刊：
影响因子：
2.9
通讯作者：
Xuelei Li;Zhiwei Li;Y. Xi;Yu-tao Shi;Xiang-ming Wang;P. Yan;F. Bao
中科院分区：
文献类型：
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作者：
Xuelei Li;Zhiwei Li;Y. Xi;Yu-tao Shi;Xiang-ming Wang;P. Yan;F. Bao
本文对华夏西南块体（云开、粤桂、粤中）的深部构造进行了新的地震资料解释。利用112个短周期三分量地震台阵，以2.5km的间距，对罗云地区推覆构造带的动力学机制和金矿化进行了研究。基于此数据集，我们能够使用P波接收函数方法成像的高分辨率的地壳结构的西南华夏地块。我们的成像结果揭示了研究区域下方的独特结构特征，包括莫霍面不连续性的显著横向变化。在罗定-云浮推覆构造带之下，莫霍面隆起表明其形成与深部熔融地幔有关（例如，软流圈地幔OIB）。沿着该构造带，Ps相和PpPs相所描述的莫霍面特征不同，这可能是由于不同莫霍面构造的正演分析所显示的局部复杂构造所致。从H-κ叠加结果中也观察到这种隆起，并且在该区域发现了低的平均Vp/Vs比（~1.65），这可能归因于其位于构造应变带内。通过与前人研究的对比分析，我们认为罗定-云浮地区的地壳抬升可能是控矿构造的一个典型场景。研究还表明，华夏地块西南部深部熔融地幔的上涌通道对金的迁移、富集和沉淀有促进作用。
This study presents new seismic data and interpretations for the deep structure in the southwest Cathaysia block comprised of Yunkai, Yuegui and Yuezhong blocks. A dense seismic array consisting of 112 short-period, three-component seismic stations was deployed to investigate the geodynamic mechanism of the nappe tectonic zone and gold mineralization with 2.5 km spacing across the Luoding-Yunfu region. Based on this dataset, we are able to image the high-resolution crustal structures of the southwest Cathaysia block using the P-wave receiver function method. Our imaging results reveal distinct structural features beneath the study region, including marked lateral variations of Moho discontinuities. Beneath the Luoding-Yunfu nappe tectonic zone, the Moho uplift indicates that its formation is related to deep melt mantle (e.g., Asthenospheric mantle OIB). Moho features depicted by the Ps image are different from those by the PpPs phase along this tectonic zone, which could be ascribed to the local complex structures as illustrated in the forward analysis for different Moho structures. Such a uplift is also observed from the H-κ stacking results and a low average Vp/Vs ratio (~1.65) is found in this region, which could be attributed to its location within a tectonic strain zone. Based on the analysis and comparisons with previous studies, we infer that the crustal uplift in the Luodin-Yunfu area could be a typical scenario of the ore-controlling structure. This study also suggests that upwelling channels of deep melt mantle in the southwest Cathaysia block could facilitate the progress of migration, enrichment and precipitation of gold mineralization.