This volume contains papers giving an interdisciplinary review of 12 major rift systems from North and South America, Africa, Europe and Asia. These papers are written by an international group of academic and industrial specialists each of whom is most knowledgeable about the respective rift. The analyzed rifts were selected on the basis of availability of an as-complete-as-possible geological and geophysical data base. Thirteen papers deal with geodynamic processes governing the evolution of rifts.A comprehensive digest of the available stratigraphic, structural, geophysical and petrological data, together with an extensive list of references, is provided for each of the analyzed rift systems. The megatectonic setting and dynamics of evolution of each basin is discussed. Geodynamic models are tested against the record of the analyzed rifts.The question of "active" as against "passive" rifting is addressed. The rifts analyzed range in age from Precambrian to Recent and cover a wide spectrum of megatectonic settings. There is discussion of the evolution of rifts in a plate-tectonic frame. The case histories are followed by discussions addressing the global setting of rifts and geodynamic processes active during the development of rifted basins.

The 8th International Conference on Basement Tectonics was held in Butte, Montana, August 8-12,1988. Historically, basement tectonics conferences have focused on such topics as reactivation of faults, the influence of basement faults on metallogeny and hyrocarbon accumulation, and the use of geophysical and remote sensing techniques to interpret subsurface and surface geology. The 8th Conference diverged from past conferences in that a unifying theme was selected. Because ancient major terrane or cratonic boundaries are often postulated to be fault zones which are subsequently reactivated, the conference was organized to examine all aspects of ancient continental margins and terrane boundaries and to compare younger (Mesozoic) ones, about which more is known, with older (Paleozoic and Precambrian) ones. Moreover, because the 8th Conference was held in the northwestern United States, a greater emphasis was placed on the Mesozoic margin of western North America and the North American shield. The seven oral sessions and four poster sessions all dealt with aspects of the conference theme: characterization and comparison of ancient continental margins. The organizers extend their thanks to those individuals who graciously consented to serve as moderators for the oral sessions: John M. Bartley, Mark S. Gettings, M. Charles Gilbert, John M. Guilbert, Donald W. Hyndman, William P. Leeman, Robert Mason, and A. Krishna Sinha. The program with abstracts volume was prepared by S. E. Lewis and M. J. Bartholomew.

This volume focuses on the geometry, kinematic development, and origin of regional segmentation structures within the basin and range province of Western North America. Contributions range from analysis of individiual structures to broad regional syntheses, including a map of basin and range structures and tilt domains. Several papers discuss the implications of regional segmentation structures in assessing seismic hazards, hydrocarbon and mineral resources, and ground-water supplies.