Peter R. Vail is being honored by the SEG in recognition of his "pioneering work in seismic stratigraphy and continuing work in unifying geophysical and geological concepts in interpretation." All who know Pete will agree wholeheartedly that this citation is richly deserved. More than any other person, Pete Vail has put geology into seismic interpretation. His creative ideas concerning sequence stratigraphy and the unifying concept of eustatic sea-level cycles, although still hotly debated in some circles, are probably as close to an original concept as most of us are privileged to see in one lifetime. Pete's worldwide experience with Exxon's exploration groups has honed the concept into an immensely practical tool in hydrocarbon exploration. His lectures, publications, and untiring teaching efforts have made his methods available to any interpreter or geologist willing to try them.
     Pete Vail graduated from Dartmouth College in 1952 with an A.B. degree. He attended Northwestern University from 1952 to 1956 where he received his M.S. and Ph.D. degrees. At Northwestern he was influenced greatly by professors Bill Krumbein and Larry Sloss, who were at the height of their work on quantified facies mapping and North American unconformity-bounded sequences. He began his career with Exxon in 1956 as a research geologist with the Carter Oil Company, an Exxon affiliate in Tulsa, Oklahoma. He and his lovely wife Carolyn reared a family of three children, who at first grew faster than his geological reputation. He relocated to Houston in 1965, after exploration and production research activities were consolidated in Esso Production Research Company, now Exxon Production Research Company. Since then, he has advanced through a series of supervisory and technical positions to the highest technical level in his company, a senior research scientist. Pete always worked within a framework of one or more "driving concepts," into which he can fit geologic facts or occurrences. He is a good listener, and avidly learns from others, especially from other disciplines. He has never been so much in love with a concept that he could not modify or drop it in the face of good evidence. His patience, thoughtfulness, and steady good nature are legendary.
     Pete's ideas evolved naturally from his first pioneering work recognizing the importance of stratal surfaces in rocks as geologic time-lines. Although his early work was with well-log pattern correlation, he soon recognized the potential of seismic data to provide the continuity and reflection patterns essential to defining stratigraphic sequences. With a wisdom greater than the advice of some of his supervisors, Pete switched to geophysics and, in that fertile environment, began his work on seismic stratigraphy. In rapid order, he recognized that:

     Because seismic reflections are generated by physical bedding surfaces, they parallel these surfaces rather than time-transgressive facies boundaries.

     Seismic reflections fall naturally into seismic sequences, with characteristic seismic facies patterns that can be used to interpret depositional environment and lithology.

     The unconformities that form sequence boundaries have the same ages when recognized in several basins worldwide.

     This synchroneity led Pete to postulate global sea-level change as a major control on the stratigraphic record, along with the local controls of subsidence and sediment supply. In 1977, Pete and his Exxon colleagues published their stratigraphic sequence concepts and sea-level curves in AAPG Memoir 26. Lately, Pete has been looking at wells, outcrops and seismic sections to study the types of stratigraphic units produced within a sequence at different positions in a given cycle of sea-level change. He also is refining the ages of sequence boundaries by dating them in European-type localities. In all his work he remains quietly confident that sequence stratigraphy has the breakthrough potential that plate tectonics had in structural geology.
     In the natural course of his work, Pete has received a great many honors from societies around the world. In 1976 the SEG awarded him the Virgil Kauffman Gold Medal for advancement of the science of geophysical exploration. He was an AAPG Distinguished Lecturer in 1975 and 1976. In 1978 he was the William Smith Lecturer for the Geological Society of London. In 1979 he was the corecipient of the AAPG President's Award for the best published paper, and in 1981 he was the corecipient of the AAPG Matson Award for the best paper delivered at the 1980 Annual Convention. In 1983 he received the Individual Achievement Award from the Offshore Technology Conference. Pete has received other honors and served on many professional committees with distinction.
     As a close personal friend, I consider it a great honor to have been asked to write this citation for Peter R. Vail. Even beyond his great technical contributions, Pete is characterized by his integrity, his dedication to his family, and faithfulness to his friends and colleagues.

     R. M. Mitchum, Jr.