Francisco Apen

About

Dr. Francisco Apen is an Assistant Professor in the School of Earth and Sustainability, where he joined the faculty in 2024. He studies the formation, evolution, and deep structure of continental lithosphere, with a focus on Earth’s earliest crust from the Archean eon, more than 2.5 billion years ago. Before coming to NAU he was a Presidential Postdoctoral Research Fellow at Princeton University.

Research

Much of the deep continental crust is inaccessible to direct observation, so Dr. Apen reads it through the fragments that volcanoes carry to the surface: lower-crustal xenoliths hosted in kimberlites and other eruptions. By combining U-Th-Pb geochronology and thermochronology of accessory minerals with major- and trace-element geochemistry, he reconstructs when cratonic crust formed, how hot it has been through time, and how heat-producing elements are distributed within it. His work spans cratons on several continents, including studies of xenoliths from the Udachnaya kimberlite in Siberia and comparative work across the Tanzanian, Wyoming, and Superior cratons.

At NAU, his lab develops high-precision isotopic methods and trains students in clean-lab geochemistry and mass spectrometry, with regional applications to the Precambrian basement of the southwestern United States.

Education

• Ph.D. Geochemistry, University of California, Santa Barbara
• B.S. Geology, University of California, Davis