New Mexico Geological Society Annual Spring Meeting — Abstracts

One north-south seismic line parallel to the long axis of the Albuquerque basin and eastwest lines across all or parts of the basin (in conjunction with the well control from the deeper exploration tests that have penetrated the Cretaceous rocks) shed significant light on the structural style and the timing history of the opening of the Rio Grande rift in this part of New Mexico.

This exploration data also shows dramatic and possibly unexpected structural partitions and sub basins as well as hidden faults and horst and graben structural geometries in the larger rift structure. Of structural importance is the recognition of Laramide thrusts and their location and effect on pre-rift structures in the basin.

Insight into the timing and abruptness of syn-rift basin fill is dramatically seen on the seismic. Also strikingly illustrated is the changing tectonic style of bounding faults on the western side of the rift margin from south to north.

Of interest is the apparent affect of the possible continuation of the Tijeras shear into and across the basin between the Belen sub-basin to the south and the Calabacillas sub-basin to the north. This zone of disturbance (Tijeras Accommodation Zone) may help put constraints on the amount of lateral movement that has taken place in the Rift - through time in this part of the rift. An additional accommodation zone may be present in the basin as a possible southwest extension of the Placitas fault.

USGS Bulletin 2184, published in 2001, supports the theory that the Albuquerque basin may contain a large basin-centered gas deposits in the rift. Recent activities by Tecton Energy, LLC working with Black Oil suggests a multi-TCF gas and hundred million-barrel oil accumulations may exist within the deeper downthrown areas of the rift.

Sub-basins in the Albuquerque basin have abundant source rock, a favorable history of maturity and probable extensive reservoir systems. Structural complexities, including Laramide thrusting, as well as stratigraphic variation will account for a portion of any trapped oil and gas. Post-Oligocene subsidence has allowed coeval maturation of the Cretaceous source and a dramatic reduction in permeability of Tertiary and Cretaceous sandstones. This may have effectively created a barrier for rapidly expelling hydrocarbons in separate sub-basins.