The relationship of the Proterozoic Hondo Group to older rocks, southern Picuris Mountains and adjacent areas, northern New Mexico
Christopher K. Mawer, J. A. Grambling, M. L. Williams, P. W. Bauer, and J. M. Robertson
At least three distinct Proterozoic rock packages are present in the southern Picuris Mountains and adjacent areas of northern New Mexico. These are: (1) an older (ca. 1765-1720 Ma) dominantly mafic metavolcanic assemblage or assemblages, examples being the Moppin, Pecos and Gold Hill Complexes, interpreted to have formed during arc-related volcanism; (2) a ca. 1700 Ma assemblage of dominantly felsic metavolcanic and metasedimentary rocks, the Vadito Group, interpreted to have formed during continental rift-related volcanism; and (3) a younger, essentially metasedimentary assemblage, the Hondo Group, a product of stableshelf deposition. Felsic intrusive bodies cut both older assemblages but do not intrude the Hondo Group. The contact between Vadito and Hondo Groups has been investigated in detail; it is deformed strongly in most areas but appears to be depositional. The contact between the older mafic assemblage and the Vadito Group is everywhere tectonic. The Marquenas Formation, a key unit in the Precambrian stratigraphy of the southern Picuris Mountains, belongs to the upper part of the Vadito Group; it is not the stratigraphically youngest sequence in the Proterozoic rocks of northern New Mexico as Soegaard and Eriksson (1986) suggest.
- Mawer, Christopher K.; Grambling, J. A.; Williams, M. L.; Bauer, P. W.; Robertson, J. M., 1990, The relationship of the Proterozoic Hondo Group to older rocks, southern Picuris Mountains and adjacent areas, northern New Mexico, in: Tectonic development of the southern Sangre de Cristo Mountains, New Mexico, Bauer, Paul W.; Lucas, Spencer G.; Mawer, Christopher K.; McIntosh, William C., New Mexico Geological Society, Guidebook, 41st Field Conference, pp. 171-177.