报告地点：教学行政楼1004会议室； 腾讯会议：816-220-088
报告时间：2023-10-12 从15:00到16:30
报告人：花君临（美国得克萨斯大学奥斯汀分校）
报告人简介：
花君临博士于2021年在美国布朗大学获得博士学位，目前在美国得克萨斯大学奥斯汀分校从事博士后研究。主要研究方向为地震散射波成像，地震波全波形反演成像，地幔地球动力过程分析，地球物理地球化学数据联合分析，环境地震学等。已在Nature Geoscience, EPSL，JGR，G-cubed, GJI等刊物发表多篇文章。
报告题目：下地幔俯冲导致的克拉通减薄
报告内容简介
Continental cratons are characterized by thick lithospheric roots that remain intact for billions of years. However, some cratonic roots appear to have been removed, with the reasons for such removal being debated. In this study, we obtain a high-resolution full-waveform seismic tomographic model for North America which newly illuminates an ongoing craton-thinning process. Extensive dripping lithosphere is imaged from the base of the craton beneath the central United States to the mantle transition zone. From geodynamical modeling, we find such dripping can be mobilized by the sinking of the deep Farallon slab, which is presently not connected to the surface and located in the lower mantle. Dripping lithosphere could be further facilitated by past lithospheric weakening processes due to volatiles released from the slab. These findings show that cratonic lithosphere can be altered by external forces, and that subducting slabs play a key role in craton mobilization and thinning even when slabs are at great depths in the mantle.