globalchange  > 气候减缓与适应
DOI: 10.1038/ngeo1982
论文题名:
Ponded melt at the boundary between the lithosphere and asthenosphere
作者: Sakamaki T.; Suzuki A.; Ohtani E.; Terasaki H.; Urakawa S.; Katayama Y.; Funakoshi K.-I.; Wang Y.; Hernlund J.W.; Ballmer M.D.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2013
卷: 6, 期:12
起始页码: 1041
结束页码: 1044
语种: 英语
Scopus关键词: asthenosphere ; basalt ; discontinuity ; high pressure ; high temperature ; lithosphere ; melt ; partial melting ; S-wave ; viscosity ; wave velocity
英文摘要: The boundary between Earth's rigid lithosphere and the underlying, ductile asthenosphere is marked by a distinct seismic discontinuity. A decrease in seismic-wave velocity and increase in attenuation at this boundary is thought to be caused by partial melt. The density and viscosity of basaltic magma, linked to the atomic structure, control the process of melt separation from the surrounding mantle rocks. Here we use high-pressure and high-temperature experiments and in situ X-ray analysis to assess the properties of basaltic magmas under pressures of up to 5.5 GPa. We find that the magmas rapidly become denser with increasing pressure and show a viscosity minimum near 4 GPa. Magma mobility - the ratio of the melt-solid density contrast to the magma viscosity - exhibits a peak at pressures corresponding to depths of 120-150 km, within the asthenosphere, up to an order of magnitude greater than pressures corresponding to the deeper mantle and shallower lithosphere. Melts are therefore expected to rapidly migrate out of the asthenosphere. The diminishing mobility of magma in Earth's asthenosphere as the melts ascend could lead to excessive melt accumulation at depths of 80-100 km, at the lithosphere-asthenosphere boundary. We conclude that the observed seismic discontinuity at the lithosphere- asthenosphere boundary records this accumulation of melt. © 2013 Macmillan Publishers Limited.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106641
Appears in Collections:气候减缓与适应
科学计划与规划

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作者单位: Department of Earth and Planetary Materials Science, Tohoku University, Sendai 980-8578, Japan; Department of Earth and Space Science, Osaka University, Osaka 560-0043, Japan; Department of Earth Sciences, Okayama University, Okayama 700-8530, Japan; Japan Atomic Energy Agency, Hyogo 679-5148, Japan; SPring-8, Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan; Center for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637, United States; Department of Earth and Planetary Science, University of California, Berkeley 94720, United States; Department of Geology and Geophysics, School of Ocean and Earth Sciences and Technology, University of Hawaii at Manoa, Honolulu, HI 96822, United States

Recommended Citation:
Sakamaki T.,Suzuki A.,Ohtani E.,et al. Ponded melt at the boundary between the lithosphere and asthenosphere[J]. Nature Geoscience,2013-01-01,6(12)
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