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The Hondo Group is a group of geologic formations that crops out in most of the Precambrian-cored uplifts of northern New Mexico. Detrital zircon geochronology gives a maximum age for the lower Hondo Group of 1765 to 1704 million years (Mya), corresponding to the Statherian period.
The Pilar Formation and Piedra Lumbre Formations were originally included in the Hondo Group. However, a metamorphosed tuff bed in the Pilar Formation yields an age of 1488 ± 6 Mya, considerably younger than the Ortega Quartzite. The Piedra Lumbre Formation likewise contains zircons dated to 1425 Mya. This suggests that the Pilar Formation and Piedra Lumbre Formation should be removed from the Hondo Group, and provides evidence supporting the Picuris orogeny.Daniel et al. 2013
The Hondo Group lies structurally below the Vadito Group in the Picuris Mountains. However, both groups have been severely deformed and metamorphosed, and the Vadito Group is thought to actually be the older of the two groups. Cross-bedding indicates that the Vadito Group has been overturned.Bauer 2004 The contact between the two groups is fairly easy to trace using a regional manganese-rich marker bed in the uppermost Vadito Group, which may have formed by syngenetic deposition from hydrothermal fluids, or a more general manganese enrichment of basin waters at the close of Vadito volcanism. Another possibility is that it is a weathering horizon. Either possibility would make it an important regional time marker.Williams 1987
The group is interpreted as fluvial to shallow marine deposition on a southward-dipping siliciclastic shelf. Together, the Vadito Group and lower Hondo Group likely represent deposition in a back-arc basin associated with the Yavapai orogeny, named the Pilar basin.
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