应我校地球物理与信息技术学院Greg Houseman院士邀请，美国科罗拉多大学博尔德分校钟时杰教授来我校学术交流并作报告，具体信息如下：

时间：5月08日，09:00-12:00

地点：教五楼227

题目：On the large-scale structure and dynamics of terrestrial planets: from Tharsis Rise on Mars to mare basalts on the Moon and to supercontinent cycles on Earth

钟时杰简介: 美国科罗拉多大学博尔德分校教授，此前曾在麻省理工学院、加州理工学院等顶尖机构从事研究工作。他的研究兴趣广泛，主要包括地幔对流与行星尺度构造演化、冰川及沉积载荷引发的地球黏弹性变形、以及高性能计算应用。美国地球物理联合会（AGU）会士。其学术产出丰富，已发表139篇同行评审论文，包括多篇发表在《自然》《自然-地球科学》《地球物理研究杂志》等顶级期刊。代表性工作涉及地幔结构动力学、板块俯冲过程、月球潮汐层析成像及黏弹性模拟软件开发等，对理解地球与行星内部过程及长期构造演化做出了重要贡献。

报告内容简介：The present-day Earth’s mantle structure, as seen in seismic imaging, is dominantly at long-wavelength, more specifically at spherical harmonic degree-2 with two large seismically slow (i.e., warm) superplume structures in the lower mantle beneath Africa and central Pacific surrounded by circum-Pacific seismically fast (i.e., cold) structures that are evidently related to the past subduction history. While the mantle structures in the geological past are largely unknown, large-scale tectonism and volcanism for the last billion years have been predominated by supercontinent cyclic process, which may hint at an even longer wavelength mantle structure at degree-1 or hemispherical asymmetry. Interestingly, the Moon and Mars also display hemispherical asymmetric structures including mare basalt volcanism on the Moon and crustal dichotomy and Tharsis volcanism on Mars that were formed in their geological past. However, it had been a significant challenge in mantle dynamics studies to produce long-wavelength convection in either mobile-lid or stagnant-lid convection regime. This presentation discusses how mantle and lithospheric viscosity structures may help generate very long-wavelength convection at degrees 1 and 2 and how long-wavelength convection may provide a framework to understand the relevant geological and geophysical observations.

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地球物理与信息技术学院
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