DOI: 10.1038/s41561-021-00760-x
论文题名: Lower crustal earthquake associated with highly pressurized frictional melts
作者: Zhong X. ; Petley-Ragan A.J. ; Incel S.H.M. ; Dabrowski M. ; Andersen N.H. ; Jamtveit B.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2021
卷: 14, 期: 7 起始页码: 519
结束页码: 525
语种: 英语
英文关键词: Caledonian orogeny
; earthquake event
; in situ measurement
; lower crust
; overpressure
; paleostress
; pseudotachylite
; Bergen Arcs
; Hordaland
; Norway
; Norway
英文摘要: Earthquakes at lower crustal depths are common during continental collision. However, the coseismic weakening mechanisms required to propagate an earthquake at high pressures are poorly understood. Transient high-pressure fluids or melts have been proposed as a viable mechanism, but verifying this requires direct in situ measurement of fluid or melt overpressure along fault planes that have hosted dynamic ruptures. Here, we report direct measurement of highly overpressurized frictional melts along a seismic fault surface. Using Raman spectroscopy, we identified high-pressure quartz inclusions sealed in dendritic garnets that grew from frictional melts formed by lower crustal earthquakes in the Bergen Arcs, Western Norway. Melt pressure was estimated to be 1.8–2.3 GPa on the basis of an elastic model for the quartz-in-garnet system. This is ~0.5 GPa higher than the pressure recorded by the surrounding pseudotachylyte matrix and wall rocks. The recorded melt pressure could not arise solely from the volume expansion of melting, and we propose that it was generated when melt pressure approached the maximum principal stress in a system subject to high differential stress. The associated palaeostress field demonstrates that a strong lower crust accommodated up to 1 GPa differential stress during the compressive stage of the Caledonian orogeny. © 2021, The Author(s). Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/169838
Appears in Collections: 气候变化与战略
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作者单位: Physics of Geological Processes, The Njord Centre, Department of Geosciences, University of Oslo, Oslo, Norway; Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany; Institute for Geology, Mineralogy, and Geophysics, Ruhr University Bochum, Bochum, Germany; Computational Geology Laboratory, Polish Geological Institute – NRI, Wrocław, Poland; Department of Chemistry, University of Oslo, Oslo, Norway
Recommended Citation:
Zhong X.,Petley-Ragan A.J.,Incel S.H.M.,et al. Lower crustal earthquake associated with highly pressurized frictional melts[J]. Nature Geoscience,2021-01-01,14(7)