Circular 75 — Geology of the Little Black Peak Quadrangle, Lincoln and Socorro Counties, New Mexico

By Clay T. Smith, 1964, 8 pages.

The Little Black Peak quadrangle lies 8 miles north of Carrizozo, New Mexico between parallels of long 105° 45' and 106° W., and between lat 33°45' and 34° N. (See plate 1). A network of ranch and mining roads branching from U.S. Highway 54, which passes northsouth through the eastern quarter of the quadrangle, brings any point to within 2.5-3 miles of motor transport. However, except for State Road 10, which traverses the northwest quarter of the quadrangle, and U.S. 54 the roads are unimproved and often impassable after rains or snow.

Scattered mesas and broad alluviated valleys averaging 6,000 feet above sea level dominate most of the area. The rugged topography of Lone Mountain and its surrounding peaks attains elevations of over 8,000 feet along the extreme eastern and southeastern edge of the quadrangle. In the southwest corner of the quadrangle a Recent lava flow, apparently derived from a small cinder cone called Little Black Peak, occupies more than 17 square miles and extends many miles to the south. Older flows from craters farther west locally modify the topography along the western margin of the quadrangle.

The geology of the eastern half of the quadrangle was published by Smith and Budding (1959) and most of the quadrangle is included in Griswold's (1959) bulletin on the Mineral Deposits of Lincoln County. Kelley (1949) describes a few of the iron deposits on the flanks of Lone Mountain, and Allen (1951) published a brief note on the Little Black Peak lava flow.

The major part of the quadrangle is typical of the semi-arid southwest; it receives less than 14 inches of precipitation annually and the vegetation is dominated by cactii, chamisa, rabbit brush, and subordinate grasses. On the higher elevations of Lone Mountain ponderosa pine, juniper, and pinon are common. Water is extremely scarce and where wells have developed meager ground-water supplies, the quality is very poor. The average mean temperature is between 55°F and 60°F, but the extremes may range from a few degrees below 0°F to l10°F.