The Nimrod Complex, an Ancient Window into East Antarctic Crustal Evolution

Non-Technical Abstract This project will examine ancient Antarctic rocks to understand the continent’s early history, including how Antarctica was once connected to other continents. By studying rock samples from the Nimrod Complex, the project will gather data on the age and makeup of these rocks, showing how Antarctica's crust formed and changed over time. This work will not only expand scientific knowledge about Earth's history but also provide valuable training for college students at multiple universities, helping to grow a diverse community of researchers who can tackle big questions in Earth science. Technical Abstract This project seeks to unravel the origin, evolution, and geological significance of the Nimrod Complex in Antarctica’s East Antarctic craton through detailed age and isotopic analysis of its igneous and metamorphic rocks. Using U-Pb zircon geochronology along with O-isotope, Hf-isotope, and trace element analyses, we will construct a comprehensive petrochronological profile of these Mesoarchean to Paleoproterozoic rocks to reveal their magmatic sources, metamorphic history, and role in the broader tectonic framework. The project aims to trace sediment sources and tectonic influences across sedimentary units spanning the Paleoproterozoic to lower Paleozoic eras, adding crucial data to supercontinent reconstructions (Columbia, Rodinia, and Gondwana) and Antarctic tectonic models. Broader impacts include collaborations between universities to develop a diverse STEM workforce, inter-laboratory partnerships, and a robust isotopic dataset that will contribute to models of Antarctic crustal evolution and its implications for ice sheet stability. 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.