This award provides support for the participation of six US scientists in a joint US-Japan seminar on "Magmatic Contribu- tions to Hydrothermal Systems: Magnitude and Importance". Hydrothermal systems form where heat and water meet in the earths crust. One important aspect of research on hydrothermal systems is the role of magmas. Continuing study of fossil and active hydrothermal systems makes it clear that magmas can contribute to these systems in several different ways but such contributions can be difficult to recognize and characterize. Difficulties arise, for example, because magmatic contributions are small in relation to the total mass of the hydrothermal system and because they undergo rapid modification by reaction with other constituents of the system. A further impediment is the wide range of disciplines involved including, for example, field geology, experimental geochemistry, thermodynamic modelling, water geochemistry and geophysics. In order to gain a comprehensive understanding of the importance of magmatic contributions to the evolution of hydrothermal systems, interaction among scientists in these fields is required. The seminar will be held Novemeber 10-16, 1991 at Kagoshima and Ebino, Kyushu, Japan. The co-organizers are Professor Stephen E Kesler, Department of Geology, University of Michigan, and Dr Eiji Izawa, Department of Mining, Kyushu University, Fukuoka, Japan. Specific topics to be discussed include (1) igneous petrology of magmas; (2) the composition of volcanic discharges and their relation to magmatic fluids; (3) fluid inclusion and geochemical studies of epithermal and geothermal systems; and (4) chemical and physical modelling of magmatic hydrothermal systems. Although the US and Japan each have many Scientists active in this field, contact between these two groups is not as extensive as it could be. The seminar will allow represent- atives from the two countries to meet and exchange information and it is anticipated that more extensive research collaboration will result.
