Metallic mineral deposits are in most places associated with igneous rocks, thus the major mining districts for copper, lead, zinc, gold, silver, and molybdenum are in complex areas of extrusive and intrusive rocks, such as near Silver City and Questa. Potash and rock salt are formed in saline basins, which explain their occurrence in the Delaware Basin area east of Carlsbad.
Gold was the lure that drew the Spanish to New Mexico in the 1500�s, but the Paleo Indians had mined turquoise (our state gem), copper, and some coal many centuries before Coronado. Mineral production in the state is a major contributor to the economy. New Mexico leads the nation in production of potash and perlite and is among the leaders in natural gas, copper, molybdenum, coal, crude oil, uranium and pumice. In addition, the state�s rocks yield significant amounts of clay, gemstones, gold, gypsum, manganiferous ore, mica, salt, sand and gravel, stone, barite, carbon dioxide, cement, iron, lead, limestone, silver, sulfur, vanadium, and zinc. The total annual value of minerals produced in New Mexico has been as high as $7.2 billion. In recent years the total value of mineral
production, from preliminary data, was more than $5 billion with state revenues about $900 million.
What magnificent benefits geology has given our state � and the nation!
The rocks determine sites of many of our cities and villages. Many of our people live along the R�o Grande rift, the geologic control for the R�o Grande, which became the focus of trails and highways amid irrigated farms and orchards, flanked by magnificent mountain ranges.
The Tijeras fault is a major break in the earth�s crust and cuts diagonally between the Sand�a and Manzanita Mountains, providing a channel for Tijeras Arroyo and a pass for I-40 from the east.
Forty miles to the west, a lowland along R�o San Jos�, north of Sierra Lucero and southeast of Mount Taylor, allows passage westward for I-40 and the AT&SF Railway. Thus our major city, Albuquerque, is at the intersection of geologically influenced north-south and east-west transportation routes.
Santa F�, at the foot of the southwestern part of the Sangre de Cristo Mountains, is the site of west-bounding faults of the range that intersect east-west trending breaks followed by the Santa F� River. Near the complex intersection, springs and marshes (cienegas) supplied water for early Indian pueblos and the Spanish/Mexicans from 1609 onward.
The geological settings for Las Cruces and Mesilla are similar to Albuquerque. They lie in the
Mesilla Valley of the R�o Grande, a rich irrigated area, traveled by I-25. Fifteen miles to the northeast, San Augustin Pass provides a natural east-west opening between the long rocky San Andr�s Mountains to the north, and to the south the rugged Organ Mountains with their majestic spires of igneous rocks, called the Organ Needles. Off to the west, the east-west US 70 and I-10 follow a broad, low plain between the Sleeping Lady Hills and Sierra de Las Uvas to the north and the basaltic rocks of the Potrillo Mountains to the south. The intersection of Camino Real "de Tierra Adentro" (King's Highway to the Interior Lands) north-south, with the east-west transcontinental highway (and railroad), locates Las Cruces.
Carlsbad is at the springs, along the Pecos River near where it crosses the buried northeast limb of the Capit�n Reef complex of cavernous limestone. Roswell and Artesia, further up the Pecos Valley, are near intersections of larger streams, draining eastward from the Sacramento Mountains to join the Pecos. Rat�n is south of Rat�n Pass, route of the AT&SF Railway and I-25. It is a canyon carved through the Mesozoic sandstones, west of the basalt-capped Rat�n and Johnson Mesas.
Farmington lies at the confluence of three rivers, the San Juan, Animas, and La Plata that drain the La Plata and southern San Juan Mountains Socorro, on the west edge of the R�o Grande Valley, is near springs fed by faults along the east flank of the Socorro Mountains.
The scenery of our Land of Enchantment is most obviously geologically controlled. Badlands are omnipresent in soft rocks such as the tertiary sandstones and siltstones along the R�o Grande from Espa�ola and Pojoaque south to Las Cruces and Sunland Park, or the multicolored Cretaceous and early Tertiary beds of the San Juan Basin at Bisti, Angels Peak, Huerfano Mesa, and near Lybrook.
Shiprock, Bennett Peak, Cabez�n, and Elephant Butte are spectacular remnants of volcanic necks, eroded throats of ancient volcanoes. Valle Grande, the core of the J�mez Mountains, crossed by NM 4, is a large caldera, the collapsed center of a huge geologically young (l.2-l.6 million years old) volcano. Outflow tuffs, the Bandelier Tuff (soft welded volcanic ash), rim Frijoles Canyon, and house the cliff-dwellings of ancient Pueblo Indians in the National Monument. North of Velarde, the R�o Grande exits the R�o Grande Gorge... Geology Continued in the New Mexico Blue Book