Structural anomalies in the Espanola Basin
— Bruce A. Black

Over the past decade, the tectonic basins of the Rio Grande rift have been the focus of an expanding interest in oil and gas exploration. This is primarily due to the recognition of the potential for Cretaceous oil and gas production in these areas. The Cretaceous section has good source rocks and reservoir-quality sands in certain parts of these basins, and this section has probably been buried to levels of organic metamorphism which are high enough for the generation of commercial quantities of oil and gas.

The tectonics of formation of the rift basins have provided abundant potential for structural traps. This structural activity, in conjunction with the stratigraphic variation in the Cretaceous package, makes a double-trap potential in those areas where the rifting has not been severe enough to have destroyed the reservoirs. In some areas, the tectonics have worked against economic oil and gas production by dropping the rocks so deeply that any organic matter has been "overcooked." The last decade of exploration (Black, 1984) has added greatly to the understanding of the rift itself, as well as its tectonic style and the stratigraphy of the contained rocks. Primarily as a result of the recent detailed mapping by a host of excellent workers too numerous to list, as well as the recent oil and gas exploration efforts along the rift, some interesting and previously unsuspected structural styles are now being documented.