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Delamination‐wedge structure beneath the Hidaka Collision Zone, central Hokkaido, Japan inferred from seismic reflection profiling
Author(s) -
Tsumura Noriko,
Ikawa Hidemasa,
Ikawa Takashi,
Shinohara Masanao,
Ito Tanio,
Arita Kazunori,
Moriya Takeo,
Kimura Gaku,
Ikawa Takeshi
Publication year - 1999
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 - 10.1029/1999gl900192
Subject(s) - geology , crust , seismology , collision , lithosphere , delamination (geology) , wedge (geometry) , continental crust , reflector (photography) , island arc , geophysics , tectonics , subduction , geometry , physics , computer security , light source , optics , mathematics , computer science
In the Hidaka Collision Zone of Hokkaido, northern Japan, the Kuril island arc collides with the northeast Japan arc. In order to better understand the collision process, new high resolution information about lithospheric structure was obtained by means of a series of seismic reflection surveys. These seismic profiles reveal distinct zones of seismic lamination in the lower crust of the Kuril arc. The upper portion of the lower crust is characterized by numerous east‐dipping reflectors. In contrast, west‐dipping reflectors dominate the lower part of the lower crust. From this reflector configuration, the lower crust of the Kuril arc is interpreted to be delaminated by the collision. The geometry of delamination is consistent with other geophysical data, as well as the peak metamorphic grades exposed in the Hidaka mountains. As earthquakes indicate that delamination here is ongoing, the Hidaka Collision Zone represents an active model for continental growth by arc accretion with delamination of lower arc crust.