|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Mines Menu:
Mines Reports:
Mines Map
Use the links at the left to return.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Mine Descriptions |
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nogales Mining District | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Location and General FeaturesThe Nogales district lies in the southwestern part of the area, on the Sonoran border (Pl. I, in pocket). It adjoins the Palmetto and Patagonia districts on the west and extends from the international boundary 10 miles northward to Sonoita Creek, and from Nogales Wash on the west to Santa Cruz River on the southeast. Nogales is at its southwest corner and Calabasa at its northwest corner. At the international boundary it has a width of 10 miles. Nogales is a port of entry between the United States and Mexico, and the principal supply point for northern Sonora and the adjoining region of Arizona. Calabasas is on the Benson - Nogales and Tucson - Nogales branch lines of the Southern Pacific Co., and the Poineer smelter is located a few miles to the north. Most of the country is less than 4,000 feet in elevation. The topogeography is general is rough, the surface being scored by deep gulches or shallow canyons, The highest point is Mount Benedict, near the center of the western part, which rises to 4,500 feet. The surface, especially on the east and north, is mostly underlain by a sheet of Quaternary gravels and wash. GeologyThe oldest formation is the quartz monzonite of Mount Benedict, which, beginning at the south base of the mountain, and occupying a belt around 2 miles wide, extends northwestward for 5 miles to a point within 1½ miles of Calabasas. Croppings of what seems to be the same rock by the roadside along Santa Cruz River in the vicinity of Yerba Buena Canyon, about 6 miles northeast of Nogales, indicate that beneath the gravels and lavas it underlies a considerable portion of the Santa Cruz Valley in this direction and probably connects with the Patagonia Mountain area of this rock on the east. It is a granitoid rock very similar to the quartz monzonite of the Washington-Duquesne camp, described on page 327, except that it is coarser grained, being locally called “bull” granite, and it contains a little more of the dark silicates, especially biotite. As seen on the north slope of Mount Benedict, the rock mass is sliced by a dominant sheeting that dips steeply to the west and by a secondary sheeting that dips to the northwest. It is also transversed by a system of east - west fissures in which the ore deposits at Mount Benedict occur. It is intruded by dikes of aplite, granite porphyry, diorite, and lamprophyric and diabasic rocks, with which the ore deposits are mostly associated. The granite porphyry forms the summit of Mount Benedict and the crests of the highest ridges, notably on the west and the south. The formation next younger than the quartz monzonite is quartz diorite, which occupies a smi-circular area on the south, extending from Nogales eastward along the international boundary for 2 miles and seemily forming but the northern portion of a large area of the same rock, most of which lies on the Mexican side of the line. East of Nogales it forms a steep hillside, and in the northeastern part of the town, east of the courthouse, the reservoir of the municipal water supply are extracted from it. It is a dark iron-gray fine-grained rock, composed principally of oligoclase - andesine in prisms, biotite and hornblende in short prismatic laths in about equal amount, and some associated augite, but the rock is low in dark silicates. Some orthoclase and considerable magnetite are also present. The formation next younger than the diorite consists of the reddish bedded volcanic tuffs which, as shown on Plate II (in pocket), occupy an irregular area of about 3 square miles in the vicinity of Nogales, extending several miles northward down Nogales Wash and northeastwards up Proto Canyon road. The tuffs are in many places covered by Quaternary gravels and are generally best exposed in the bottoms and sides of the drainage ways. Their general structure is indicated in section E-F, Plate III (in pocket). In the southwestern part of the district, at Nogales, as shown in Plate VI, B. the beds overlap the diorite on the hillsidr already mentioned. In the northern part of the town the courthouse stands upon the contact between the diorite and the tuffs. At 3 miles east of Nogales and a third of a mile north of the Mexican line black basault, occurring in a small north-south area, shown on Plate II, intrudes the Quaternary gravels. LODE DEPOSITS The lode deposits occur principally in the middle of the western part of the district in the quartz monzonite area, mainly at Mount Benedict, about 4 miles north of Nogales, and 2½ miles northwest of Mount Benedict at the Reagan Camp. The Mount Benedict deposits are mainly gold-bearing, and those of the Reagan camp carry wulframite.
aka Gold Hill District. Mount Benedict area between Santa Cruz river and Nogales Wash. This district is in Santa Cruz county.
Location23S, 14E6 Mineral ProductsAu, Pb, Ag, Cu, W (Mo)6 Geology1. Irregular fissure veins, with spotty, often banded, pyrite, cerussite, galena, and minor copper carbonates and sulfides, in Jurassic quartz monzonite that has been strongly sliced by sheeted fracturing and intruded by splite, granite, porphyry, diorite, lamprophyre, and diabase dykes. 2.Irregular and lensing, comb structured quartz-wulfamite veins with minor scheelite associated wth dikes cutting Jurassic quartz monzonite. 3. Spotty gold placer deposits reported in Guebabi Canyon (NE, T23S, R14E) and on east slope of Mt. Benedict.6 Types of operation and productionMostly shallow shaft, tunnel and open cut operations. Worked as early as the 1850's and sporadically up to 1967. Estimated and recorded production would amount to some 1,100 tons of ore containing about 1,019 oz. of gold, 95 tons of lead, 14,200 oz. of silver and 9 tons of copper. About 1,500 pounds of 50% WO3 concentrates may have been shipped. Output from gold placers unknown but probably relatively small.6.
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
