The Consortium for Continental Reflection Profiling, known as COCORP, has now been operating for more than a decade since its original experiment in Hardeman County, Tex. Ten years ago, the idea of a transcontinental deep reflection section seemed an impossible dream, but today, major segments of such a profile have been surveyed. Completion of such a section by the time of the International Geological Congress (to be held in Washington in 1989) is very likely.
When the project began, our knowledge of the deep structure of the continents was rudimentary at best. From earthquake seismology, large-scale seismic refraction experiments, and gravity data, we had a general picture of regional variations in crustal velocities and depth to the mantle, but the details were unknown. From a few exposures and from studies of xenoliths, we had some idea of the nature of the lower crust, but only in special areas. Initial COCORP experiments focused on specific areas in which existing geological and geophysical data suggested that deep reflections could be found and that specific questions could be answered. When these proved successful, the program ventured into the unknown and began a broad reconnaissance of the continental crust of the United States. The success of the early experiments did not go unnoticed by others, and deep reflection experiments are now being conducted in a number of countries.