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The Santa Fe Group is a succession of Neogene sandstone, siltstone, conglomerate, and intercalated volcanics that fills the basins of the central Rio Grande rift. Data from twelve deep wells and recently released seismic profiles in the Albuquerque rift basin document a dramatic basinward thickening of the Santa Fe Group across the major basinal faults. Abbreviated thicknesses of less than 1,220 m (4,000 ft) occur on the structurally higher, outer benches, but the section thickens to more than 4,270 m (14,000 ft) in the basin center, on the downthrown sides of the basin’s seismically defined master normal faults.

Thickness of the Santa Fe mimics the basin’s structural asymmetry. In the north, it forms an eastward-thickening clastic wedge in response to eastward tilting of the north part of the basin toward the westward-flattening master faults (Rio Grande, Sandia, and San Francisco-Placitas faults). In the south, it thickens westward toward the Santa Fe-Coyote master faults along the southwestern margin of the basin. As a result, depositional rates of the Santa Fe were rapid on the structurally deep, master-fault sides of the basin in the northeast and southwest and relatively slow on the basin’s hinge sides in the northwest and southeast. At the northeast-trending Tijeras accommodation zone, which divides the north and south halves of the basin, the section thickens abruptly to the north in the basin center, indicating a major dip-slip as well as probable strike-slip component of motion between the two subbasins.

Much of the thickening in the Santa Fe Group seems to occur in the upper Miocene part of the section, possibly implying a phase of accelerated crustal extension at that time.

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