New Mexico Geological Society
Special Publication - 9
Ash-Flow Tuffs: Their Origin, Geologic Relations and Identification and Zones and Zonal Variations in Welded Ash Flows
Jonathan F. Callender, ed, 1980, 104 pages, NMGS.
Twenty years have passed since publication of U.S. Geological Survey Professional Papers 366, Ash-flow tuffs: Their origin, geologic relations and identification, by C. S. Ross and R. L. Smith (1961), and 354-F, Zones and zonal variations in ash-flows, by R. L. Smith (1960). As these papers are now being republished, perhaps a few words are appropriate to clarify their historical evolution and to view them in the context of the present time. Clarence Ross and I began an intensive general study of microscopic and field characteristics of "welded tuffs" in 1948, in the hope that such a study would aid our interpretation of the Bandelier Tuff, Jemez Mountains, New Mexico. The study led to a general overview which became Professional Paper 366. Professional Paper 366 was written during the late 1940's and early 1950's.