Bulletin 68—Gypsum resources of New Mexico

By R. H. Weber and F. E. Kottlowski, 1959, 68 pp, 2 tables, 5 figs., 10 plates, 1 index.

This bulletin is designed to satisfy the growing demand for information concerning gypsum deposits in NM and the possible utilization of known deposits of this mineral. An earlier study by Darton (1920), listing and summarily describing most of the large deposits in the state, is now out of print. Moreover, some smaller deposits of possible local value, not listed previously, have been located recently. The utilization of gypsum depends on many factors, which must be considered for each deposit and each locality individually.

This report is chiefly a reconnaissance survey of gypsum deposits in NM. The large accessible deposits of possible large-scale economic use are emphasized, but small reserves that may be of local use are also noted. Most of the bedded gypsum is of middle Permian or Upper Jurassic age, whereas the gypsum dune sands and gypsite, formed from weathering of bedded or dune deposits, are of Quaternary age. Thick, relatively pure gypsum beds occur within 50-75 mi of the Rio Grande valley from the Rio Chama southward to Truth or Consequences; thinner beds crop out near the surface along the Pecos River from Acme and Roswell south to the NM-TX state line; and the extensive gypsum dune sands of the Tularosa Basin are not only a world-famous scenic attraction, but include a huge reserve of pure gypsum that is outside the White Sands National Monument.

Areas of large gypsum deposits are serviced by the Atchison, Topeka, and Santa Fe Railway from Lamy to Albuquerque and Belen, west to Laguna, east to Vaughn, and south to Engle; by the Southern Pacific Railroad from Vaughn and Ancho to Alamogordo; and by the Atchison, Topeka, and Santa Fe Railway from Acme and Roswell to Carlsbad and Malaga. Paved state and federal highways provide additional access to or near most of the major deposits.

Gypsum deposits known to be of large extent and purity were examined in the field, samples collected, and brief summary descriptions prepared for inclusion in this report. Large outcrop areas of possible economic deposits were examined at the more accessible points. Small deposits, deposits difficult to mine, and relatively inaccessible deposits have been described from published reports, unpublished and oral descriptions, or from cursory examination. Where possible, chip samples of gypsum beds were taken for chemical analyses. Many of the gypsum outcrops, however, are covered by a thick crust of gypsite of by impure leached gypsum, or are well exposed only in impassable cliff faces; at these places only grab samples were collected.