Gold and Base Metal Deposits in the Mexican Altiplano, States of Zacatecas and San Luis Potosi, Central Mexico

Abstract

The first part of the trip travels northwest from San Luis Potosi to Zacatecas. An extensive collection of Tertiary volcanic rocks covers the base sediments west of San Luis Potosi. Rocks are mainly rhyolite tuffs, latites, and layered volcanic limolites. Another important volcanic center is the Los Pinos, which is a complex formed by clastic rocks, red beds, trachytes, and rhyolite tuffs. Historically, mining in the area has been active and was first reported in epithermal Au-Ag vein mineralization related to the mid-Tertiary sequence formed by domes, associated lava flows, and ash-flow tuffs. Penon Blanco (San Jose) is an emergent mining district that has been explored recently. Rocks reported in the area include the basement, formed by Cuesta del Cura limestone and rocks of the Chilitos Formation. This sequence of rocks is intruded by the Penon Blanco batholith, which has created a halo of marble rock in the contact with the sedimentary and volcanosedimentary rocks. Mineralization occurs in quartz veins and skarn, and main ores are silver, lead, zinc, and little copper. The city of Zacatecas is situated within a horst formed by NE-trending normal faults. The Mesozoic Chilitos Formation, siltstones, phyllites, and rhyolites are the main host rocks for mineralization in the region. Two of the major producer mines are located nearby: The Francisco I. Madero and the Cozamin deposits. The Madero deposit is hosted in thin-layered siliceouscarbonaceous units, with chlorite, calcite, and pyrite alteration that can be seen only underground. The Cozamin deposit occurs in veins hosted by the Chilitos Formation, andesites, phyllites, and siltstones. General vein trending is N 40° to 65° W dipping 65° to 75° NE, and the entire group of veins is known as the Mala Noche vein system. Good morning! Take the side road, San Luis Potosi-Mexico, to the east. 0.4 Turn left on Colorines street and take the San Luis-Mexico Highway to the west. 0.9 Jump into the Distribuidor Vial Benito Juarez and take the road San Luis Potosi-Matehuala to the north. 2.1 Turn left and follow the Boulevard Rio Santiago to the west. 2.6 Turn right on Fray Diego de la Magdalena Street. 1.1 To the right you'll see the Tangamanga local park, a Formula 3 racing course. Continue straight to Zacatecas by way of the Federal Highway no. 49. 4.1 Pass over the bridge of the Anillo Periferico Norte. 14.6 Route passes by cultivated areas and a series of small