The objective of this project is to develop an experimental basis for understanding the behavior of volatiles in submarine basaltic magmas. The principal investigators will measure (1) solubility of carbon dioxide over a range of mid-ocean ridge basalt compositions, temperatures and pressures; (2) solubility of water over the same parameter range and determine the effect of water solubility on that of carbon dioxide; (3) kinetics of bubble nucleation and growth. During these experiments, the Fe2+/Fe3+ ratio will be determined in order to unravel the effects of degassing on oxidation state of the magmas. %%% Magmatic volatiles control the style of volcanic eruptions. Experiments such as the ones to be carried out in this project will provide fundamental data on the solubility of two critical volatiles in magmas, water and carbon dioxide. These data will help to understand how magmas degas as they ascend and erupt and to determine if kinetic fractionation among volatile species occur during bubble growth.