The San Andres Formation in the Palo Duro Basin is a middle Permian carbonate-evaporite sequence situated between two red-bed units, the underlying Glorieta and the overlying undifferentiated Queen-Grayburg sequences.
The Van Horn Mountains caldera is a small (~10-km2) igneous center in the Trans-Pecos volcanic province. The caldera formed 37 to 38 mya during eruption of the first of two ash-flow tuffs related to the caldera.
Fractures and veins in strata of the Palo Duro Basin area, Texas Panhandle and eastern New Mexico, are characterized using data from outcrop and core studies and from fracture identification log analysis.
Statistical analysis of chemical data on Texas Eocene coals revealed startigraphic and geographic trends in lignite quality. Chemical data on near-surface coals wre obtained from various private and public sources. Seams from deep-basin coals were compared.