Bulletin 121—Coal deposits and facies changes along the southwestern margin of the Late Cretaceous seaway, west-central New Mexico

Compiled by G. H. Roybal, O. J. Anderson, and E. C. Beaumont, 1987, 82 pp., 13 tables, 42 figs.

This bulletin was originally prepared for the 100th Annual Meeting of the Geological Society of America, in Phoenix, Arizona as part of the Coal Division Field Trip. Four days of roadlogs (from Albuquerque to Phoenix via the San Juan Basin) and eight invited papers were compiled in this volume.

The field-trip route goes through areas with excellent exposures of the lower two-thirds of the Late Cretaceous coal-bearing sequences and their marine counterparts, showing the facies relationships along the transgressive-regressive shoreline in the southern San Juan Basin. The field trip goes through west-central New Mexico. The purpose was to look at the recent activity in the coal mining industry and the current geological investigations in the region. The route of the field trip goes through areas with excellent exposures of the lower two-thirds of the Late Cretaceous coal-bearing sequences and their marine counterparts, showing the facies relationships along the transgressive-regressive shoreline in the southern San Juan Basin. Several stops are planned to look at these sequences and discuss their depositional environments. The coal mines that will be visited are different in both size and method of operation, a reflection on the extent of the coal resource and the quality characteristics of the coal.

The papers included in this bulletin cover the geology of west-central New Mexico, the hydrogeology of the area, and the individual coal mines to be visited. Most of these articles represent recent work of the authors in areas which had not previously been looked at in such detail. It is hoped that these contributions are representative of the present knowledge of the Late Cretaceous in the southern San Juan Basin and outlying areas. Articles included are Coal mining and production in New Mexico by G. H. Roybal, Geology and mining activity in the Lee Ranch area, McKinley County, New Mexico by E. C. Beaumont, Characterization of New Mexico coals, Menefee and Crevasse Canyon Formations by F. W. Campbell and G. H. Roybal, Water supply in southern San Juan Basin, New Mexico by J. W. Shomaker and R. W. Newcomer, Jr., McKinley mine by W. R. Erickson, S. L. Johnson, J. C. Klinger, N. A. Wildman, and J. Wilson, Stratigraphy and coal occurrences of the Tres Hermanos Formation and Gallup Sandstone, Zuni Basin, west-central New Mexico by O. J. Anderson and G. D. Stricker, Coal geology of the Salt Lake coal field by F. W. Campbell, Hydrogeologic considerations in mining, Nations Draw area, Salt Lake coal field, New Mexico by W. J. Stone and B. E. McGurk, and Large-scale combustion test of Fence Lake coal at the Coronado Generating Station by M. A. Greenberg.