Magmatic activity and mineralization along the Capitan, Santa Rita, and Morenci lineaments in the Chupadera Mesa area, central New Mexico
McLemore, Virginia T., Zimmerer, Matthew
The Capitan, Santa Rita, and Morenci lineaments are regional crustal structures that focused magmatic activity and mineralization across central New Mexico, especially in the Chupadera Mesa area. The diversity of igneous rocks and mineral deposits in this region suggests highly fractionated and differentiated magmas. The existing K/Ar and 40Ar/39Ar ages indicates magmatic activity occurred during multiple pulses, rather than one single event. The easternmost intrusion along the Capitan lineament is the 27.9 Ma Railroad and Camino del Diablo dikes, whereas the Springerville volcanic field could define the western limit. The Lincoln County porphyry belt (LCPB) is a N-S belt of Tertiary porphyritic calc-alkaline to alkaline rocks that were emplaced in at least two pulses: 32-38 Ma and 26-30 Ma and are associated with Au-Ag-Te veins, REE-Th-U veins, Fe (±Au) skarns, and porphyry Mo deposits. The 28.8 Ma Capitan pluton forms the eastern part of the LCPB and is the largest Tertiary intrusion in New Mexico. The zoned Capitan pluton is associated with Fe skarns and REE-Th-U-Au vein deposits. East of Socorro several small deposits of Cu-Ag-U (±Fe, Au) vein and Rio Grande rift (RGR) barite-fluorite-galena deposits are found along faults; they are not directly associated with igneous activity and could represent migration of mineralizing fluids along rift structures. 40Ar/39Ar ages and field relationships suggest that RGR deposits formed during the last 10 Ma coincident with the later stages of rifting in central New Mexico, locally near the intersection with regional lineaments and other structures. Most of the available ages of igneous activity are K/Ar dates; detailed, high precision geochronology will be required to fully understand the temporal relationships between regional magmatic activity and mineralization.
- McLemore, Virginia T., Zimmerer, Matthew, 2009, Magmatic activity and mineralization along the Capitan, Santa Rita, and Morenci lineaments in the Chupadera Mesa area, central New Mexico, in: Geology of the Chupadera Mesa, Lueth, Virgil W.; Lucas, Spencer G.; Chamberlin, Richard M., New Mexico Geological Society, Guidebook, 60th Field Conference, pp. 375-386.