This multi-author book has been prepared by an international group of geoscientists that have been active in rift research since the late 1960s. In 1984, an informal, grass-roots study group was initiated to compare individual research results and to explore in greater depth the apparent differences and similarities in the interpretations from various rift systems. The group became known as the CREST working group, an acronym of Continental Rifts: Evolution, Structure and Tectonics, which not surprisingly became the title of this book.Continental Rifts: Evolution, Structure, Tectonics presents an overview of the present state of understanding and knowledge of the processes of continental rifting from a multidisciplinary, lithospheric scale perspective. The chapters have been structured on each rift system in approximately the same synoptic sequence, so as to facilitate comparisons of rifts by the reader. The book complements its predecessors by presenting a more unified picture. It succeeds in presenting the status of a representative majority of the continental rift systems that have been at the forefront of recent research. For students and experienced researchers alike, this book will be of significant value in assessing the current state of knowledge and in serving as a framework for future research.

Complete Bouguer and isostatic residual gravity maps of the Anadarko basin, Wichita Mountains, and surrounding areas in parts of Oklahoma, Kansas, Texas, and Colorado were compiled using gravity data from 11,023 stations. The most prominent features on these maps are gravity highs over the Amarillo-Wichita and Arbuckle uplifts and the Muenster arch. These highs are assumed to be caused by Late Proterozoic-Cambrian high-density gabbroic and volcanic rocks that are believed to be part of an aulacogen. Other features on the maps include (1) a north-northeast-trending high that may be associated with a southern extension of the Midcontinent gravity high, about one degree of longitude west of the Nemaha uplift, (2) an arcuate gravity high in the southeastern corner of the study area that probably represents the southern margin of the North American continent during the Late Proterozoic, (3) a very large gravity low associated with the Arkoma basin and Ouachita Mountains thrust belt, (4) gravity lows associated with most of the Paleozoic basins in the region, (5) no apparent gravity expression of the Nemaha ridge, and (6) broad gravity highs that are probably caused by dense mafic igneous rocks in the basement. These broad gravity highs and the fact that the gravity low over the Anadarko basin is higher over the deepest part of the basin than in other parts of the basin indicate that many, if not most, of the anomalies are caused by differences in basement rock types and densities.