Accretion-collision tectonics in mobile belts is one of the most
important new topics in solid earth science. A special seminar on this
subject, the Oji International Seminar on Accretion Tectonics, was held
from the 10th to 16th September, 1981, in Tomakomai, Hokkaido, Japan. It
was sponsored by the Japan Society for the Promotion of Science and the
Fujihara Foundation of Science, organizers were S. Uyeda, Earthquake
Research Institute, University of Tokyo, Amos Nur, Department of
Geophysics, Stanford University, and M. Hashimoto, Department of
Geology, National Science Museum, Tokyo. More than fifty geoscientists,
thirty from Japan and twenty from abroad, met together to present
findings from their recent studies and exchange ideas about
accretion-collision phenomena in the circum-Pacific mobile belts. Two
field days were also spent in the Horokanai area, central Hokkaido, to
examine and the Horokanai ophiolite. The the Kamuikotan high-pressure
metamorphic rocks latter is a fragment of ancient ocean floor crust that
has been obducted onto the Kamuikotan rocks at the time of collision of
the Okhotsk Micro-continent with Asia. The seminar was by no means a
large congress. However, to the best of our knowledge, it was the first
international conference on accretion-collision tectonics. The meeting
was highly successful and we believe that it has opened an important new
era in the study of plate tectonics.