This field conference was designed to assemble a group of Quaternary researchers to examine the possibility of using the Zuni-Bandera volcanic field in western New Mexico as a test area for evaluating and calibrating various Quaternary dating techniques. The Zuni-Bandera volcanic-field is comprised of a large number of basaltic lava flows ranging in age from about 700 to 3 ka. Older basalts are present in the Mount Taylor volcanic field to the north. Geologic mapping has been completed for a large portion of the Zuni-Bandera volcanic field and a number of geochronological investigations have been initiated in the area. While amending this conference, please consider how you might bring your expertise and capabilities to bear on solving the many problem in Quaternary geochronology.

A two-dimensional numerical model was constructed for the alluvial aquifer in the area of the Uranium Mill Tailings Remedial Action (UMTRA) Project Shiprock, New Mexico, site. This model was used to investigate the effects of various hydrologic parameters on the evolution of the ground water flow field. Results of the model are useful for defining uncertainties in the site conceptual model and suggesting data collection efforts to reduce these uncertainties. The computer code MODFLOW was used to simulate the two-dimensional flow of ground water in the alluvium. The escarpment was represented as a no-flow boundary. The San Juan River was represented with the MODFLOW river package. A uniform hydraulic conductivity distribution with the value estimated by the UMTRA Project Technical Assistance Contractor (TAC) and a uniform recharge distribution was used. Infiltration from the flowing artesian well was represented using the well package. The ground water flow model was calibrated to ground water levels observed in April 1993. Inspection of hydrographs shows that these levels are representative of typical conditions at the site.