Hannah Aird

Research Interests:

• Igneous Petrology (granite formation)
• Economic Geology (formation of copper and gold deposits)
• Geoscience Education

CURE-E Course: Optical Mineralogy/Igneous and Metamorphic Petrology (ERTH 403, formerly GEOS 402/403), first introduced with CURE-E in Spring 2022

Project Title: Magmatic Processes in the Bald Rock Pluton of the northern Sierra Nevada

The Sierra Nevada (e.g., Yosemite) are famous for their dramatic topography and vast expanses of beautiful white rocks. These granites have been well studied for decades because the deep valleys allow a three-dimensional view into a crystallized magma chamber, and magma chamber processes are not yet fully understood because they occur deep underground at inaccessible pressures and temperatures so cannot be directly observed. The rocks of the northern Sierra Nevada are older and less deeply eroded than the high Sierra, so still display relationships with the surrounding metamorphic rocks. However, little work has been done on the northern Sierran rocks since the theory of plate tectonics became widely accepted by the scientific community.

The aim of this study is to determine the magmatic processes involved in the formation of the Bald Rock pluton (BRP), near Oroville, CA, with the goal of helping the USFS update its interpretive signage on the Feather Falls hiking trail. Students will work in small teams to develop a research question and design a sampling and analysis plan, which they will then carry out. The project will span about half of the semester. Depending on the specific research questions, investigative activities may include:

• Fieldwork for sample collection
• Hand sample description (lithology)
• Preparing thin sections (slicing a rock to 0.3mm and attaching it to a glass plate for microscope analysis)
• Thin section description through a microscope (petrography)
• Bulk rock geochemistry with the ICP-MS
• Bulk rock geochemistry with the XRF
• Textural analyses with the SEM
• Localized geochemical analyses with the SEM 

Results will be interpreted and mock-ups of interpretive signage for each project will be presented to the USFS.