The Channeled Scabland

As the Mariner and Viking spacecrafts photographed the large channels on Mars, they generated a renewed interest in the erosional effects of large quantities of running water. As the debate continues whether these channels were caused by catastrophic floods, wind, lava or mudflows, it is imperative to examine, in the field, the morphologic criteria which appears to be diagnostic of catastrophic flooding. Hence this field conference to the Channeled Scabland.

Although we now propose to use the Channeled Scabland as a testing area for the Martian flood hypotheses, the flood origin of the scabland itself has a history of intense controversy. Ironically, many of the arguments against catastrophic floods on Mars are the same as those advanced against Bretz' "outrageous hypothesis" for the scabland origin. These include the source of such large quantities of water, the mechanism of its sudden release and the magnitude and nature of sub-fluvial erosion. Also, some of the alternative fluids proposed for channel generation on Mars were advanced in the debate about the origin of the Channeled Scabland.

THE CHANNELED SCABLAND intends to provide a thorough description of the morphology of the region and a discussion of its inferred cause, including the hydrodynamics of high-velocity flood erosion. It is designed as a guide, written specifically for the Comparative Planetology Field Conference in the Columbia Basin in June, 1978. The editors hope, however, that the book will provide a useful guide also for future field trips and an introduction to the area for geologists who intend to launch their own studies on specific attributes of this fascinating landscape.

The book is dedicated to J Harlen Bretz in recognition of his pioneering advocacy of the flood origin of the scablands. It is also an expression of our appreciation of the many other scien-

tists who directly or indirectly have contributed to our understanding of the scabland origin. The ideas on the Channeled Scabland set forth in this book have matured through discussions with numerous oolleagues, including Jon C. Boothroyd, William С Bradley, J Harlen Bretz, Robert K. Fahnestock, Roald Fryxell, Harold E. Malde, George E. Neff, Peter С Patton, Russell G. Shepherd, Richard B. Waitt, Jr. and Paul L. Weis.

The field studies and analytical work on the problem involved the assistance of PauUne M. Baker, Frances A. Heaton, R. Craig Kochel, and John M. MacGregor. Field work by V. Baker was initially supported by National Science Foundation Grant GA-21478. Subsequent studies were supported by NASA Grants NGR 44-012194 and NSG-7326, Planetology Program Office, and by The Geology Foundation, The University of Texas at Austin. Field studies by D. Nummedal have been supported by NASA Grant NSG-7076, Planetology Program Office, and the University of South Carolina.

P. Jeffrey Brown and Duane T. Eppler, the University of South Carolina, provided great help in guidebook editing, logistics planning and coordination of the field trip.

We extend our sincere appreciation to John S. Shelton for providing numerous illustrations for the book and to Henry D. Neumann for assistance in obtaining the photos for the color plates.

Neither the book nor the field trip would have been possible without the enthusiastic support by Stephen E. Dwornik, translated into financial assistance through grants to the participating principal investigators in NASA's planetary geology program.

We also thank Priscilla Ridgell and Carleen Sexton for the typing, Burk Scheper for the photo-technical work and Nanette Muzzy for the graphics. <...>