Funds will defray the analytical laboratory costs involved in a 40Ar/39Ar geochronological research program in the classic Sambagawa high-pressure terrane and adjacent lithotectonic units exposed on the islands of Shikoku and Honshu, Japan. Travel and all logistical expenses of the project are covered by grants awarded to R.D. Dallmeyer from the U.S. National Science Foundation ($12,154: INT-8815932) and to A. Takasu (Shimane University) from the Japan Society for the Promotion of Science. The proposed Japanese collaborators (A. Taksu and T. Hirajima) have been investigating the thermal evolution of the Sambagawa and adjacent belts for over 10 years. The U.S. collaborator (R.D. Dallmeyer) has been utilizing the 40Ar/39Ar dating method in complex polymetamorphic terranes in major orogenic belts. The specific goals of the proposed research are to calibrate the time-temperature-pressure evolutionary histories of the Sambagawa terrane and adjacent areas and to coordinate the results with various proposed tectonic modes. The expected results will be of importance not only to the Japanese archipelago, but to high- pressure subduction complexes of all ages throughout the world.
