Aleisha Johnson

I am an isotope geochemist interested in the rise of O2 in Earth’s atmosphere and the compositional evolution of Earth’s continental crust. To this end I employ stable metal isotopes (Ti, Zr, Hf, Mo, Fe) in a variety of modern and ancient systems to learn about these processes that led to Earth’s current state as a persistently habitable planet. While my PhD focused on Mo weathering and cycling at ultra-low levels of O2 to understand Archean atmospheric redox, more recently I have focused on pairing isotope systems like Ti and Fe in magmatic environments to understand how stable isotopes record the formation and recycling of continental crust.

I joined the University of Arizona as a postdoctoral researcher in the fall of 2022. Previously I graduated with a BS in Geology from the University of Wisconsin – Eau Claire, followed by a PhD in Geochemistry from Arizona State University. Most recently I completed an NSF EAR Postdoctoral Fellowship at the University of Chicago.

Research Interests:

Isotope Geochemistry and Metal Cycling; Paleoredox Proxies; Co-Evolution of Life and the Environment; Magmatic Differentiation; the Composition of Earth’s Continental Crust