报告题目：Deep hydration and lithospheric thinning at oceanic transform plate boundaries

报  告  人：王志凯 博士 英国南安普顿大学

报告时间：7月17日（周三）下午15:30

腾讯会议：379 604 598 

召  集  人：于志腾 副研究员

报告人简介：王志凯 博士，2022年毕业于法国巴黎地球物理研究所（IPGP），获地球与环境科学博士学位，目前为英国南安普顿大学牛顿国际研究员。主要研究方向为通过地球物理方法探究大洋中脊-转换断层的性质和大洋岩石圈的构造演化。以第一作者在Nature Geoscience、Nature Communications等国际期刊发表学术论文5篇。

报告内容：Transform faults accommodate the lateral motions between lithospheric plates, producing large earthquakes. However, the deep structure of these faults remains enigmatic. Here we present ultra-long offset seismic data from the Romanche transform fault in the equatorial Atlantic Ocean that indicates the presence of a low-velocity anomaly extending to ~60 km below sea level. We performed three-dimensional thermal modelling that suggests the anomaly is probably due to extensive serpentinization down to ~16 km, overlying a hydrated, shear mylonite zone down to 32 km. Below 32 km depth is interpreted to be a low-temperature, water-induced melting zone that elevates the lithosphere–asthenosphere boundary, causing substantial thinning of the lithosphere at the transform fault. The presence of a thinned lithosphere at transform faults could explain observations of volcanism, thickened crust and intra-transform spreading centres at transform faults.

                                                                                                           自然资源部海底科学重点实验室