As part of our assessment program on underground CO2 storage, we studied the dissolution of feldspar in aqueous solutions of supercritical CO2 at 25, 50, 65, and 80 degrees C with a constant CO2 pressure of 10 MPa. Atomic force microscopy (AFM) was then used to observe nanoscale dissolution features on the feldspar surface. The average dissolution rates of anorthite during the initial I week of dissolution were estimated from surface retreat based on vertical cross-section profiles. (c) 2004 Elsevier Ltd. All rights reserved.