各位老師和同學(xué)：
應Eiichi Takahashi研究員邀請，日本Japan Agency for Marine-Earth Science and Technology的M. Hamada研究員近期將訪(fǎng)問(wèn)我所，并于本周三和周五做“同位素室學(xué)術(shù)報告”2017年第36次報告和第37次報告。歡迎大家參加并積極參與討論！
報告題目1：Hydrogen in nominally anhydrous minerals: An overview and volcanological applications
報 告 人：Prof. M. Hamada (Japan Agency for Marine-Earth Science and Technology)
報告時(shí)間：10月25日（周三）上午10:00
報告地點(diǎn)：綜合樓702會(huì )議室
報告題目2：Water in arc basalt magmas: Constraints from high-pressure experiments and FTIR analysis
報 告 人：Prof. M. Hamada (Japan Agency for Marine-Earth Science and Technology)
報告時(shí)間：10月27日（周五）上午10:00
報告地點(diǎn)：綜合樓702會(huì )議室
報告人簡(jiǎn)介:
M. Hamada 研究員，2006年在東京大學(xué)獲得博士學(xué)位，2013以來(lái)在日本的Japan Agency for Marine-Earth Science and Technology工作。M. Hamada研究員目前在EPSL、CMP等國際頂級刊物發(fā)表了多篇關(guān)于島弧巖漿成因、巖漿過(guò)程水的行為、洋島玄武巖的起源和地球化學(xué)變化、以及巖漿減壓過(guò)程氣泡成核的動(dòng)力學(xué)方面的論文。他開(kāi)發(fā)了新的測量水含量的技術(shù)，可以利用FTIR測量無(wú)水礦物水的含量，特別是長(cháng)石礦物中水的含量。
10月25日報告摘要:
Trace amounts of hydrogen are commonly accommodated in the crystal structure of nominally anhydrous minerals (NAMs). Since the 1960s, such hydrogen in NAMs has been studied as an indicator of water？rock interactions and a proxy of H2O dissolved in silicate melts. In the last 15 years, many experimental studies have been performed to determine partition coefficients of hydrogen between peridotite minerals (olivine, orthopyroxene, clinopyroxene, etc.) and melt. Plagioclase, which is the most common mineral in Earth’s crust, is one of the NAMs. However, hydrogen in plagioclase was less studied compared with those NAMs in mantle rocks. We analyzed hydrogen in plagioclase collected from Izu-Oshima volcano, a frontal-arc volcano in Izu arc, by using FTIR. Based on the FTIR analysis, we propose that 1) basalt magmas beneath Izu-Oshima volcano are H2O-saturated from shallower level to deeper level and 2) they undergo polybaric degassing during their ascent in the conduit and eruption.
10月27日報告摘要:
The slab-derived fluids released from a subducted slab ascend into the mantle wedge, so that arc magmas, in general, are characterized by their hydrous nature. Estimation of H2O in arc basaltic rocks provides important constraints on pre-eruptive P-T conditions of magmas. However, it is difficult to estimate concentration of dissolved H2O in melts by using erupted volcanic rocks because H2O is subject to degas during eruption.
Conducting high-pressure melting experiments is one of powerful approaches to constrain H2O in arc basaltic magmas. Micro-analysis of melt inclusions by using FTIR or SIMS are alternative method to estimate water content in magma. Dr. M. Hamada has been working on water content in magma of Japanese Quaternary volcanoes combining both high pressure experiments (Hamada et al. 2008 CMP) and FTIR analysis. In particular, he developed a new method to estimate water content in magma by analyzing water content in plagioclase using FTIR (Hamada et al. 2011, 2013 EPSL). In this talk, he will overview these works and will show his most recent works.