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Elastic wave velocities in isochemical granulite and amphibolite: Origin of a low‐velocity layer at the slab/mantle wedge interface
Author(s) -
Tatsumi Y.,
Ito K.,
Goto A.
Publication year - 1994
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/93gl03171
Subject(s) - granulite , slab , geology , mantle (geology) , subduction , mantle wedge , metamorphic facies , shear (geology) , geochemistry , petrology , geophysics , seismology , geomorphology , tectonics , facies , structural basin
Simultaneous measurements of compressional and shear wave velocities, Vp and Vs, in granulite and amphibolite with identical chemistry were carried out from room temperature to 850°C at 1 GPa. Both Vp and Vs in granulite and amphibolite decreased linearly with increasing temperature. The values of Vp and Vs at 700°C are 7.75 km/s and 4.37 km/s for granulite, and 7.40 km/s and 4.21 km/s for amphibolite, respectively. 3–4 % lowering of elastic wave velocities in hydrous amphibolite compared with anhydrous granulites may be consistent with seismological observations indicating the presence of a low‐velocity layer at the slab/mantle wedge interface in subduction zones.