This award supports an integrated stratigraphic, paleontologic, structural, geochemical, and geochronological study of the Ellsworth Mountains. The purpose of this work is to determine the depositional and tectonic history of this region during late Proterozoic and Paleozoic time. The Ellsworth-Whitmore Mountains block is an important tectonic element within the collage of continental crustal blocks of West Antarctica. This investigation will be accomplished by careful geological mapping and sample collecting for purposes of microstructural kinematic analysis, trace and rare-earth geochemical analysis, and geochronological work. The project will use 40Ar/39Ar and U/Pb isotopic dating methods to define the absolute timing of events. This work will help to constrain tectonic models for an important region of West Antarctica. In particular, a proper understanding of this block is key to evaluating hypotheses about the formation or breakup of supercontinents, such as Rodinia in the Neoproterozoic or Gondwana in the Paleozoic.