The basic problems of processes of planetary rifting are addressed from the following viewpoints: speculation as to the origin and development of rifts; rifts on other planets; tectonics; geology; chemistry of the lithosphere; physics of the lithosphere; and resources associated with rifting. The state of ignorance on the subject and its remedy is debated.Co-Sponsored by the Lunar and Planetary Institute, American Geophysical Union, National Science Foundation, National Aeronautics And Space AdministrationCompiled by Lunar and Planetary Institute.PARTIAL CONTENTS: Timing and chemistry of igneous events associated with the southern Oklahoma aulacogen / M.C. Gilbert--Pulsation tectonics and rifting of continental margins / R.E. Sheridan--Magmatic evidence on the chemical and thermal evolution of continental rifts / D.K. Bailey--Experimental petrology as a probe of rifting processes / R.F. Wendlandt--Petrogenesis of silica-saturated evolved rift magmatic rocks / E.R. Neumann--Late Cenozoic volcanism of the northern New Mexico-southern Colorado portion of the Rio Grande rift / M.A. Dungan, D. Phelps, J.C. Stormer, D.P. Blanchard, R. Nielsen, N. McMillian, and R. Thompson--Late Cenozoic basalts of the southern Rio Grande rift, southern New Mexico, West Texas, and northern Chihuahua, Mexico / J.M. Hoffer--Thermal and rheologic history of the upper mantle beneath the southern Rio Grande rift : Evidence from Kilbourne Hole xenoliths / G.Y. Bussod and A.J. Irving--Geochemical constraints on the evolution of the lower crust beneath the Rio Grande Rift / E.R. Padovani and S.R. Hart--Crustal magnetization beneath the Rio Grande Rift based on xenoliths from Kilbourne Hole and Potrillo Maar / P.J. Wasilewski and E.R. Padovani
