GEO-CM: Investigating the interplay between magma source, thermal history, and fault reactivation in the Colorado Mineral Belt

About This Grant

This project investigates the geologic controls on economic mineralization. The work will be conducted near a known mining region in Ouray, Colorado. This area was mined for gold in the late 1800s and early 1900s. Today, critical minerals and rare earth elements are important to the global economy. This work will take a new look at this gold mining district and see if there is evidence for critical minerals. The study area is within the Colorado Mineral Belt. The project will investigate when and how igneous activity occurred. This work will conduct chemical analyses of the rocks in the area to see if critical minerals are present. This project will analyze the faults and fractures surrounding the area. The work will conduct a teacher training module for 5-12 grade educators. This project will train undergraduate and graduate STEM students. The geologic research will improve understanding of the controls on critical mineral deposits. This will help improve how geoscientists explore and assess potential mineral resources. This project will investigate the interplay between structures, magma source, and thermal history at the previously mined Ouray stock and surrounding alteration halo. This location was selected because of its presence within the Colorado Mineral Belt and next to the Ancestral Rocky Mountain Uncompahgre Uplift (with associated deep-seated structure). The Ouray stock shares similarities with models of volcanic-hydrothermal systems associated with ore deposits. However, the Ouray stock lacks geochemical analyses needed to determine the source of magma that fed the intrusion, there are minimal constraints on the thermal history of the intrusion and host rock, and the structural context and relation to other parts of the Colorado Mineral Belt are undefined. This work will address four research questions. 1) What is the rare earth element composition of the Ouray stock and host rock? 2) What is the timing of emplacement and cooling of the Ouray stock, and what is the timing of mineralization? 3) What is/are the source(s) of the magma that formed the Ouray stock? 4) What is the role of pre-existing structures on the location of the Ouray stock? These questions will be investigated with multiple techniques. 1) New whole rock geochemical analyses of the Ouray stock and host rock. 2) New geochronologic, thermochronologic, and peak temperature analyses will be made of the intrusion and host rocks. 3) New hafnium isotopic analyses from the intrusion will be conducted to assess magma source. 4) New mapping and kinematic modeling of deformation features will be conducted to determine the role of structures. Addressing these questions has implications for investigating how the interplay between structural inheritance, magma source, and thermal history may influence mineralization timing and distribution of critical minerals in a previously mined Laramide pluton, with implications for other plutons within the Colorado Mineral Belt. This project will assess the roles of geologic and geochemical processes that concentrate critical minerals and will contribute toward characterization and potential discovery of critical minerals within the Colorado Mineral Belt. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.