Circular 157—Sedimentology of Mesa Rica Sandstone in Tucumcari Basin, New Mexico

By J. E. Gage and G. B. Asquith, 1977, 14 pp., 4 tables, 21 figs.

Study of the geometry, transport directions, and type represented by the Mesa Rica Sandstone (Cretaceous). The study area is located in east-central New Mexico. The area is rectangular with dimensions of 56 mi north-south and 69 mi east-west. The approximate geographic boundaries are the Texas-New Mexico border, the Canadian River, NM-129, and the northwestern escarpment of the Llano Estacado.

Determining the geometry, transport directions, and delta type represented by the Mesa Rica Sandstone in the Tucumcari Basin area was the purpose of this study. Various techniques included utilizing grain-size analysis, paleocurrent analysis, isopach trends, and quantitative sedimentary structure analysis. An additional goal was to determine the relationship of the Mesa Rica Sandstone to the Dakota Sandstone north and northwest of the Tucumcari area.

The Mesa Rica Sandstone in the Tucumcari Basin of east-central New Mexico represents deposits from a lobate sand-rich delta complex. Log-probability curves of the grain-size distributions when compared to the work of Visher indicate environments ranging from distributary channels to marine wave deposits.

The Mesa Rica delta prograded into the marine Tucumcari Basin from the north as shown by the south-trending to southwest-trending paleocurrent directions, and the decrease in mean grain size and thickness to the southeast, south, and southwest indicates a transition from predominantly fluvial to predominantly marine conditions. If the Mesa Rica Sandstone is correlative with the lower fluvial interval of the Dakota Sandstone north and northwest of the Tucumcari Basin as suggested by Scott, then the Dakota Sandstone represents the fluvial facies of the Mesa Rica marine delta complex.