Named as one of six members of Lake Valley formation for Tierra Blanca Creek, Otero Co, NM along which are excellent exposures in vicinity of Nunn Ranch. Type section measured on Apache Hill at the type section of Lake Valley formation, NE1/4 NW1/4 sec 21, T18S, R7W, near Lake Valley, Sierra Co, NM in Orogrande basin. Consists of medium-bedded, gray to brown, coquina beds containing light-colored chert nodules that cap the Mississippian section at Lake Valley, Sierra Co, Orogrande basin, and grade imperceptibly down into the soft, blue-gray marls of Nunn member (new) of Lake Valley. Most of basal beds of Tierra Blanca are interbedded with blue-gray marl so that a definite line between underlying Nunn and Tierra Blanca is difficult to draw. Upper part is invariably gray to brown coquina with as much as 50 percent light-colored chert. Is a cliff former and in most places makes a vertical scarp along the mountain front. Is overlain by Arcente member (revised) of Lake Valley. Thickness ranges from 125 ft in Percha Creek area to 10 ft in parts of Sacramento Mountains, both in Otero Co, Orogrande basin. Also found in sections measured in Luna, Sierra, Dona Ana, and Grant Cos, Basin-and-Range province and Orogrande basin. Not found in Franklin or Hueco Mountains, TX. Rapid lateral changes in thickness common where biohermal structures are present. Is of Osage (Mississippian) age. Measured sections, cross sections, areal extent maps.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Laudon and Bowsher (1949) have reported 15-30 ft of cherty crinoidal limestone without distinctive fossils overlying the Tierra Blanca member of Lake Valley formation in the southern part of Cooks Range (Luna Co, Basin-and-Range province). These beds were tentatively referred to Kelly limestone. The absence of faunal evidence, and the lack of any definitive break between the formations, has led the author to consider them to be part of Tierra Blanca member of Lake Valley formation, and they were so mapped. Section 3 ft thick measured near Lake Valley in SW1/4 NW1/4 sec 20, T18S, R7W, where member overlies Nunn member of Lake Valley and unconformably underlies unnamed Pennsylvanian conglomerate. Brachiopod and coral fossils. Mississippian age. Stratigraphic chart. Geologic map.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Is member of Lake Valley Limestone in southwest NM. Columnar sections at Bear Mountain, Grant Co, and in North Cooks Range, Luna Co (both in southeastern Basin-and-Range province), and at Lake Valley, Sierra Co (western Orogrande basin). Overlies Nunn Member of Lake Valley at Lake Valley and North Cooks Range; overlies Alamogordo Member of Lake Valley at Bear Mountain, where Nunn Member is absent, apparently due to facies change. Unconformably underlies Tertiary volcanics at Lake Valley; unconformably underlies Pennsylvanian Oswaldo Limestone of Magdalena Group in North Cooks Range and at Bear Mountain. Arcente and Dona Ana Members of upper part of Lake Valley are missing at Pennsylvanian erosion surface within study area. Biostratigraphic dating with foraminifers indicates upper part of zone 7 (Osagean, Lower Mississippian) from lower part of member at Bear Mountain. Regional correlations on fig. 2; is correlated with upper part of Witch Member of Keating Formation in Escabrosa Group in Pedregosa basin. Age is Osagean (Early Mississippian).

Source: GNU records (USGS DDS-6; Denver GNULEX).