Pg. P15-P16. Redondo Creek Member of Valles Rhyolite of Tewa Group. Is a petrographically distinctive rhyolite, distinguished by sanidine-rimmed plagioclase phenocrysts and complete lack of quartz phenocrysts; typically contains biotite phenocrysts. Maximum thickness about 500 feet. Conformably overlies lake beds or sandy sediments of Valles caldera fill; in San Luis Creek, conformably overlies Deer Canyon Member of Valles Rhyolite. Unconformably underlies Valle Grande Member of Valles Rhyolite. [Age is Pleistocene.]
Named from rhyolite dome and associated dikes and flows exposed at head of Redondo Creek [near La Cueva, Jemez Springs 15-min quadrangle, Sandoval Co., north-central NM].
[Type locality: in steep slopes on west side of Sulphur Creek, btw. Sulphur Springs and La Cueva, Jemez Springs 15-min quadrangle, Sandoval Co., north-central NM.]

Source: Publication; US geologic names lexicon (USGS Bull. 1520, p. 256).

Pg. 24, geologic time scale (inside front cover). Redondo Creek Member of Valles Rhyolite. Rhyolite sample from pumiceous rock in Redondo Member, in Jemez Mountains, Seven Springs quadrangle, Sandoval County, New Mexico, yielded a fission-track age of 1.7 +/-0.12 Ma (zircon). Age calculated using decay constants of Steiger and Jager, 1977 (Earth Planet. Sci. Letters, v. 36, p. 359-362). [Pliocene to Pleistocene (boundary at 1.8 Ma), based on time scale of Berggren, 1972, Lethaia, v. 5, no. 2, p. 195-215.]

Source: Publication.