2017 年 AGU 和日本地球物理学会（ JPGU ）联合举办一次规模较大的国际性会议，这是 AGU 和 JPGU 第一次大范围的联合。原来 JPGU 也有一些国际专题，但是都比较少，本次地球物理共有 75 个 Session ，一大半为 International session （英语的 Session 有 49 个），会议时间为 2017 年 5 月 20 日至 25 日，地点位于东京边上的千叶市（ Makuhari Messe, Chiba ）。 本次会议中我们有两个专题，内容主题是岩石圈和地幔结构，目前我们已经邀请了四位专题报告。 摘要投稿日期将于下月开始（ Jan. 6 – Feb. 16, 2017 ）。欢迎大家关注日程，早做明年的出国参会计划，投稿参会。开会地点就在东京附近，交通十分 方便。 五月份也是日本最为美丽的季节。 会议 session 的网址： http://www.jpgu.org/meeting_e2017/session_list/index.html 我们的 Session 如下： S-IT30Characterizing/contrasting seismic discontinuities in the oceanic andcontinental lithosphere S-IT31Revisit Bullen's layer C - Mantle transition zone and beyond 邀请报告 Invited talk ofS-IT30 Brain Kennett (ANU) -latest view on lithospheric heterogeneity, discontinuity and plate formation,with a focus on similarity/difference between continental/oceanic lithosphere. Emily J Chin (Scripps) - worklinking fabric, geochemistry and stratification in arc lithosphere ( http://scrippsscholars.ucsd.edu/e8chin/content/microstructural-and-geochemical-constraints-evolution-deep-arc-lithosphere ) Invited talk ofS-IT31 Nicholas J Mancinelli (Brown University) -conducted global studies of scattered body waves to improve constraints on thelength-scales and strength of heterogeneity throughout the mantle https://www.linkedin.com/in/nicholas-mancinelli-619ba533 Maxim D. Ballmer (ETHZ) -the composition, dynamics and evolution of the Earth’s (and planetary)mantle(s). Magma-ocean crystallization processes sets up the initial conditionfor mantle convection. Density and viscosity variations as a function oftemperature, major-element (e.g., Mg/Si ratio) and minor-element (e.g.volatiles) composition, as well as mineralogy (e.g., grain-size, fabric)control the evolution of the mantle through time, and to the present day. http://jupiter.ethz.ch/~ballmerm/ Session 介绍 S-IT30Characterizing/contrasting seismic discontinuities in the oceanic andcontinental lithosphere (Xuzhang Shen, YoungHee Kim, Teh-Ru Alex Song, RainerKind) The lithospheric seismic structure is crucial tounderstandings of the creation, modification and destruction of the plates.Oceanic lithosphere is typically thought to be the outcome of melting ofundepleted mantle and subsequent cooling, whereas continental lithosphere,especially beneath the cratons, is often considered as the result of plumemelting, stacking oceanic lithospheres or/and arc collision. However, laterepisodes of hydration, small-scale convective instability or/and andmetasomatism, among other possibilities, potentially facilitate themodification and disruption of oceanic and continental lithosphere. Seismic discontinuities of variable sharpness, strength and polarity of theiramplitudes are now frequently observed at many regions and defy predictionsfrom a simple thermal boundary. More sophisticated modeling efforts suggestthat some of these seismic discontinuities may be consequences of fineanisotropic layerings. The session focuses on characterizing seismic structures of lithosphere andtheir implications on the formation and evolution of the oceanic and cratoniclithosphere. We welcome abstracts that focus on new seismic observations withdiverse dataset, improvement of the robustness of seismic processing/modeling,and welcome cross-disciplinary efforts that link seismic observations,deformation experiments, geodynamic modeling and geological/petrofabric data. S-IT31 RevisitBullen's layer C - Mantle transition zone and beyond (Teh-Ru Alex Song,YoungHee Kim, Xuzhang Shen, Hitosi Kawakatsu) Large seismic velocity gradient between 400 km and 1000km depth led Bullen in 1940 to the construction of the layer C, which includesthe mantle transition zone and uppermost lower mantle defined in thepreliminary reference earth model, or PREM. While phase transition of olivineto its high pressure polymorphs generally defines the 410 and 660 km seismicdiscontinuities, several interesting findings associated with the lower half ofthe layer C are somewhat difficult to be reconciled with the olivine phasetransition alone. First, just below the 660 seismic discontinuities, traveltime and triplication data typically define a large velocity gradient down toabout 800 km depth. Second, observations of high frequency seismic scatteringoriginating from 700 to 1000 km depths remain puzzling. Third, in some latestglobal tomographic models, positive radial anisotropy appears prominent near orbelow the slab in the upper lower mantle. Fourth, downgoing slabs andupwellings interpreted in recent tomographic models are not always linked tothe olivine phase boundaries and they frequently experience strong distortionnear the bottom of the layer C. If the internal structure of the Earth and its layering are evolved from longterm mantle convection and mechanical mixing due to plate construction ordestruction over billions of years, one may attempt to understand the nature ofseismic complexities in the layer C as a whole. One may ask how the layer Ccontrols modern mass and heat advection in the mantle. If the layer C iscompositionally inhomogeneous with depth, one may wish to refine its densityprofile and discuss plausible dynamic consequences. This session solicits all efforts characterizing seismic properties in allwavelengths in the layer C, and we also encourage integrated andmultidisciplinary efforts to help untangle the nature and the dynamic impact ofthe layer C.
标签: JPGU
