Bulletin 53—Geology of Questa Quadrangle, Taos County, New Mexico

By P. F. McKinlay, 1957, 23 pp, 1 table, 1 plate, 1 index.

This report describes the geology and mineral deposits of the southwestern quarter of the Taos Range of the Sangre de Cristo Mountains, a fault-block range with complex geology, and the Taos Plain, a Bolson, to the west. The study was made by the NM Bureau of Mines and Mineral Resources in cooperation with the U.S. Geological Survey as part of the entire Taos Range. Field work began in the summer of 1947 and continued during the summers through 1950. Work done in the northern half of the area has been reported in Bulletin 42.

Questa quadrangle is in the north-central part of Taos County. The region is served by State Highway 38, which runs north from Taos through Questa to Colorado. State Highway 38 extends east from Questa to Red River; State Highway 111, a graded road, extends west from near Arroyo Hondo on Highway 38 to Tres Piedras. Other roads extend up Rio Hondo and Cabresto Canyons. The principal towns are Questa, Arroyo Seco, and Arroyo Hondo.

Maximum relief within Questa quadrangle is about 5,600 ft, with the lowest point, 6,500 ft, on the Rio Grande at the southern border, and the highest point, 12,106 ft, Lobo Peak. The area can be divided into two physiographic subdivisions: (1) the Taos Range of the Sangre de Cristo Mountains, and (2) the Taos Plain.  

The Taos Plain covers the western half of the quadrangle. Elevations range from 7,000 ft at the rim of the Rio Grande gorge to 8,000 ft along the mountain front to the east. The Rio Grande gorge extends southward across the plain and ranges in depth from 300 ft at the northern edge of Questa quadrangle to 500 ft at the southern edge.

The Taos Range of the Sangre de Cristo Mountains covers the eastern half of the quadrangle. The prominent features are the steep western front, high peaks and glaciated valleys, and the Red River and Rio Hondo drainages. The region is semiarid, although the range in altitude produces large variations in temperature and precipitation. The annual precipitation varies from less than 8 to more than 20 inches. Temperatures in winter ranges from -25º to -50ºF, those in the summer from 30º to -90ºF. The higher precipitation and lower average temperatures occur in the mountainous areas. From May to October, the moisture falls as rain or hail, except on the high peaks, where snowstorms may occur throughout the year.