Correlation and paleoenvironments of the Jackpile sandstone (Upper Jurassic) and intertongued Dakota Sandstone-lower Mancos Shale (Upper Cretaceous) in west-central New Mexico
— Donald E. Owen

The main purpose of this paper is to summarize interpretations of the correlation and paleoenvironments of rock-stratigraphic units adjacent to the Jurassic-Cretaceous unconformity in an irregular arcuate- shaped outcrop belt between Grants and Santa Fe, New Mexico (fig. 1). The study area is somewhat complicated structurally because it includes the junction of the Colorad Plateau (San Juan Basin), Rocky Mountains (Nacimiento uplift), and Basin and Range (Rio Grande graben). Included in thi area is the type area of the Jackpile sandstone and the type section of the most of the members of the Dakota Sand- stone lower Mancos Shale intertongued complex. The Jackpile is the principal host rock for uranium in the study area, the Dakota is a reservoir rock, and the Mancos a source rock for gas and oil in the San Juan Basin.

This paper is part of a larger, in-progress study of the greater San Juan Basin region encompassing the rock-stratigraphic units discussed here plus the Burro Canyon Formation (Lower Cretaceous). The Burro Canyon Formation is present to the north of the study area