Geomorphic history of part of the Tucumcari Lake drainage basin, New Mexico
— David W. Love

Geomorphological reconnaissance and sedimentological study were done to aid archaeological investigations of sites along the route of Interstate 40 south of Tucumcari, New Mexico, initiated by archaeologists from the Museum of New Mexico during the spring and summer of 1979. The following review of the geomorphic evolution of the area is taken from an unpublished report on file at the Museum of New Mexico. This review is based on field observations, interpretations from aerial photographs (1951 and 1971), previous literature concerning the geomorphic history of the area (Dobrovolny and Townsend, 1946; Judson, 1953; Trauger and Bushman, 1964; Hawley, written comm. 1964; Berkstresser and Mourant, 1966; Trauger et al., 1972; Leonard and Frye, 1975; Frye et al., 1978, 1982; Barnes et al., 1983; Dolliver, 1984; Hawley, 1984) and discussions with J. W. Hawley. 

 

The affected archaeological sites are peripheral to an unnamed watershed south and east of Tucumcari (herein called Tucumcari drainage) which drains into Tucumcari Lake, a natural lake (Fig. 1). Most of the investigation concentrated on sites salvaged prior to construction of the Mountain Road interchange on 1-40. Although the archaeological sites were occupied only during the past few thousand years, the processes and surficial deposits result from development of the geomorphic system over the past few million years. Of particular importance is the evolution of the Tucumcari drainage itself and its relationship to surrounding drainages. Because detailed examination of all deposits over the area remains to be done (except for archaeological trenches), this review will be chronologic rather than presenting description and interpretation separately. The preliminary work in the area suggests the following general phases of landscape development: (1 ) Pliocene evolution of drainages after deposition of the Ogallala Formation, (2) formation of the highest remnant Pleistocene surfaces and deposits northeast of Tucumcari, (3) formation of lower geomorphic surfaces, (4) deposition of gravel deposits capping a ridge 2 km east of Tucumcari, (5) incision of an ancestral Tucumcari drainage, (6) formation of an extensive piedmont around the base of Tucumcari Mountains, (7) further incision of the Tucumcari drainage below its present level, (8) erosion of the margins of the Tucumcari drainage, particularly the former piedmont slopes, and consequent deposition along the floor of Tucumcari drainage and Tucumcari Lake and (9) subsequent erosion and deposition in, and adjacent to, the Mountain Road interchange south of Tucumcari. The amount of time involved in each of the above phases remains to be determined, but some of the phases lasted much longer than others. The entire region as been uplifted nearly 1000 m during the past 10 m.y. (Gable and Hatton, 1983) and has undergone episodic changes in climate. In contrast to regional uplift, solution subsidence may have affected the landscape position of some of the early deposits (Gustayson et al., 1980; Dolliver, 1985).