This MRI award provides funding to acquire a next-generation Multicollector ? Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS) equipped with a collision/reaction cell and MS/MS mass filter. The instrument will be housed within the Arizona LaserChron Center (ALC), an NSF-supported Community Facility at the University of Arizona (UA) that supports research in Earth Sciences. It will be co-managed between ALC and the Arizona Heavy Isotopes Laboratory (AHIL). Science questions pursued by ALC and AHIL researchers include reconstructing the igneous evolution of Earth, Moon, Mars, and other planetary materials; the timing of volcanic eruptions; tectonic evolution and uplift of mountain ranges; transport and accumulation of sediments; formation of base metal deposits and other strategic and energy resources; reconstructing the history of Earth?s climate, including patterns of ice sheets and tracing of aeolian (loess) deposits. The new instrument will directly support the research efforts of ~350 faculty members, professional geologists, and students that visit the ALC each year, by making state-of-the-art analytical methods accessible to the broader Earth Science community. Furthermore, the instrument will provide new opportunities for students and researchers to learn the theory and methods of mass spectrometry; data acquisition and processing; and offer educational and outreach activities for a broad user base including participants from under-represented minority groups in STEM. The new MC-ICPMS will complement other ICPMS and laser-ablation systems available at ALC by enabling improved accuracy/precision using existing analytical methods, development of new techniques only achievable with the proposed instrumentation, as well as increasing analytical capacity. In particular, research in ALC will emphasize: i) developing new techniques in laser-based MC-ICPMS geochronology that take full advantage of the novel collision/reaction cell and MS/MS capabilities (e.g., Rb-Sr); and ii) providing greater capacity to meet the growing community demands for U-Th/Pb geochronology and complementary Lu-Hf isotope analysis. We anticipate that in-situ Rb-Sr methods applied to feldspar and mica will transform petrochronology and detrital mineral studies in much the same way that zircon U-Pb has impacted many different areas of Earth science research. AHIL research will emphasize the development and application of emerging techniques in non-traditional stable isotopes of Ti, Zr, and Hf in bulk-rocks and minerals to study high-temperature petrologic processes influencing magmatism, fluid flow, crust-mantle differentiation, and the distribution of critical elements. Through connections with researchers in the UA Lunar and Planetary Laboratory, we will leverage these novel capabilities to study aspects of planetary geochemistry/geochronology that bear on Earth?s origin and evolution. Through community outreach and research training for underrepresented students and postdoctoral researchers, the PI/Co-PIs will ensure that the new MC-ICPMS takes advantage of UA?s position as an R1 Hispanic Serving Institution and American Indian and Alaska Native-Serving Institution for enhancing diversity in geosciences, while addressing exciting new questions in petrology, geochemistry, tectonics, and planetary sciences. 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.