New Mexico Geological Society Annual Spring Meeting — Abstracts

Southwest New Mexico is part of the larger southwestern North America Laramide porphyry belt, which stretches from Arizona into New Mexico and further south into Mexico. The primary products of these deposits are copper, molybdenum, and gold, but additional by- and co-products can be extracted from these deposits such as Platinum Group Elements, tellurium, indium, gallium, germanium, and others, of which many are classified as critical minerals. These deposits are largely Laramide (~80-45 Ma) in age, and are a result of hydrothermal interactions with calc-alkaline igneous plutons from the arc magmatism of subduction zones. In New Mexico, these deposits occur alongside younger mid-Tertiary (Eocene-Oligocene, ~40-30 Ma) deposits that are thought to be a result of transitional arc magmatism to extensional magmatism. A new geochronological study of southwest New Mexico was necessary in order to resolve the question of whether some deposits are Laramide or mid-Tertiary. New argon-argon geochronology, whole rock and trace element geochemistry, and electron microprobe analyses have resolved questions on whether some deposits are Laramide or mid-Tertiary in origin. Several districts were confirmed as either Laramide or mid-Tertiary, while others were determined to have both deposit styles present in the same district. The updated geochronology and characterization of these districts leads to the updating of the mineral-resource potential of these districts, as well as the different types of critical minerals that have the potential to occur with each deposit style.