Open AccessMagnetotelluric imaging of crustal magma storage beneath the Mesozoic crystalline mountains in a nonvolcanic region, northeast Japan
Author(s) -
Umeda Koji,
Asamori Koichi,
Negi Tateyuki,
Ogawa Yasuo
Publication year - 2006
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2006gc001247
Subject(s) - geology , crust , magnetotellurics , magmatism , mesozoic , subduction , mantle (geology) , tectonics , lithosphere , seismology , geochemistry , petrology , geomorphology , electrical resistivity and conductivity , engineering , structural basin , electrical engineering
Mesozoic crystalline mountains (Iide Mountains) in a nonvolcanic region of the Northeast Japan Arc were imaged by wide‐band magnetotelluric soundings. A two‐dimensional model shows that an anomalous conductive body (<10 Ωm) is clearly visible beneath the Iide Mountains. The conductor widens with increasing depth and extends from the near‐surface down to the base of the crust and perhaps into the upper mantle. The location of the conductive body correlates with high‐temperature hot springs with high 3 He/ 4 He ratio, thinning of the brittle seismogenic layer, and anomalies of low seismic velocity. We conclude that the conductor reflects the presence of partial melts in the crust, related to renewed magmatism in the present‐day subduction system.