Abstract: Sedimentology of Cretaceous Mesa Rica Sandstone, Tucumcari Basin, New Mexico

John E. Gage, George B. Asquith

The Cretaceous 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 indicate environments ranging from distributary channels to marine wave-dominated deposits. The rapid lateral and vertical transition from cross-stratified fluvial distributary-channel deposits to bioturbated and burrowed horizontally stratified marine-wave deposits suggests that the Mesa Rica delta should be classified as a wave-dominated, Rhone-type delta.

The Mesa Rica delta prograded into the marine Tucumcari basin from the north as shown by the south to southwest-trending paleocurrent directions, and the decrease in mean grain size and thickness to the southeast, south, and southwest (lobate geometry). Also, a decrease in percent cross-stratification to the southeast, south, and southwest, accompanied by an increase in percent bioturbation and burrowing, 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, then the Dakota Sandstone represents the fluvial facies of the Mesa Rica marine-delta complex.

AAPG Search and Discovery Article #90970©1977 AAPG Southwest Section Meeting, Abilene, Texas