报告题目： The Lithosphere-asthenosphere boundary and the Gutenberg discontinuity: The role of water, CO2 and melt

报  告  人： Satish C. Singh 教授  法国巴黎地球物理研究所（IPGP）

报告时间： 8月22日（周五） 14:30开始

报告地点： 1号楼1002会议室

召  集  人： 于志腾  研究员

报告人简介：

Dr. Satish C. Singh is a distinguished seismologist and earned his PhD at the University of Toronto. He has been working on combining seismic reflection and refraction data, developing innovative techniques like joint tomographic and full waveform inversion. He has applied these methods to fundamental scientific problems, including studying gas hydrates, magma chambers, and crustal structures. He has also focused on advancing seismic survey design, leading to the use of new streamer configurations and ultra-long offset data recording. Dr. Singh has published over 200 papers in journals like Nature and Science. He was elected American Geophysical Union Fellow in 2010, awarded the Grand Prix of the French Academy of Sciences in 2011, and the European Research Council (ERC) Advance Grant in 2013/2024, and the SEG/AAPG Distinguish Lecture in 2018. Dr. Singh likes developing new methods to address fundamental problems and believes that science is great fun. 

报告内容：

Plate tectonics theory describes rigid lithospheric plates moving over a weak, convecting asthenosphere, separated by the lithosphere-asthenosphere boundary (LAB). Understanding LAB's depth and nature is crucial for studying oceanic lithosphere evolution. Using advanced seismic reflection data from the Atlantic Ocean, we identify two distinct boundaries: 1) an upper reflection deepening with age along the ~1250°C isotherm, representing the thermal LAB as a melt-solid boundary with volatile-rich melt; 2) a stable ~75 km-deep Gutenberg discontinuity marking a frozen dehydration boundary between dry and hydrated mantle. Key findings include: thermal anomalies rejuvenate lithosphere by uplifting LAB and erasing the Gutenberg discontinuity; incomplete melt extraction creates lithospheric heterogeneity; transform faults show hydration-induced thinning. These results demonstrate that both boundaries originate at ridge axes, with plate motions primarily driven by slab-pull and ridge-push forces.

此次访问期间(8.21-26)，Satish Singh教授将在海底科学与划界全国重点实验室开展地震层析成像的指导工作，办公室为1号楼410房间，欢迎大家前来交流讨论。

自然资源部海底科学重点实验室

2025年8月18日