各位老師和同學(xué):
應徐義剛院士邀請,倫敦大學(xué)皇家霍洛威學(xué)院Prof. Jason P. Morgan將于本周四下午做“同位素室學(xué)術(shù)報告”2018年第30次報告。歡迎大家參加并積極參與討論!
報告題目:Asymmetric Plume Flow During South Atlantic Rifting: Causes and Consequences
報 告 人:Prof. Jason P. Morgan(倫敦大學(xué)皇家霍洛威學(xué)院)
報告時(shí)間:11月15日(周四)下午15:00
報告地點(diǎn):綜合樓701會(huì )議室
報告人簡(jiǎn)介:
Pro. Jason P. Morgan,倫敦大學(xué)皇家霍洛威學(xué)院地球物理學(xué)教授,國際著(zhù)名地球物理學(xué)家、地球動(dòng)力學(xué)家。曾在麻省理工學(xué)院、斯克里普斯海洋研究所、GEOMAR中心、康奈爾大學(xué)任職。其研究領(lǐng)域包括大陸巖石圈力學(xué)性質(zhì);金伯利巖的起源;蛇紋巖化對俯沖板片的影響;地幔對流機制;大洋中脊動(dòng)力學(xué);大洋下軟流圈在地幔對流中的作用;俯沖板片脫水及水在俯沖帶動(dòng)力學(xué)中的作用;大陸裂谷與金伯利巖在地幔柱理論中的作用;大陸裂谷、溢流玄武巖、隕石撞擊在生物大滅絕中的作用等。為了獎勵其在大洋中脊、俯沖帶、地幔柱以及三者與軟流圈地幔相互作用等研究領(lǐng)域的杰出貢獻,EGU在2016年授予其Augustus Love獎?wù)隆rof. Morgan在Nature、Geology、JGR、EPSL等刊物發(fā)表論文300余篇,H-index 50,引用次數9000余次。
報告摘要:
During rifting along a plume-influenced continental margin, excess volcanism is defined by the transition from rifting to spreading being associated with much thicker than normal oceanic crust. The current conventional model is that the excess volcanism should be associated with the region of influence of a plume head, roughly centered about the starting plume tail’s location below its quasi-spherical rising plume head. Here we investigate a different plume-linked hypothesis for the formation of excess volcanism during early plume-influenced continental rifting with 3-D calculations. We find that, in South Atlantic, plume material is predicted to be pulled southward from the Tristan plume as the rift develops, irrespective of whether the initial Tristan plume lay beneath the present-day African or South American continental lithosphere. Isostatic compensation of plume material ponding beneath the growing region of extending, thinning, continental lithosphere creates the elevated regional relief above the region where SDRs form — no plume head is needed to explain the source of this excess transient topographic anomaly.
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