The geocentric axial dipole (GAD) model for Earth's magnetic field has been used for some 50 years as a first approximation, allowing for paleomagnetic studies of a wide variety of rocks. The position of ancient continents, velocities of spreading oceans, deformations of plates and correlations of strata are all possible using the GAD model. But, it is quite obvious from continued measurements of the magnetic field over historic time that there are higher order variations in this simple model, such as the flux lobes at high latitude persistent in the radial component at the core/mantle boundary. Models based on archeomagnetic data as well as results from young lava flows and lake sediments extend detailed images of the field back several thousand years. The time-averaged field (TAF) over the last 5 myr is modeled using data from terrestrial lava flows and marine sediments, but results are not unambiguous and the data are not robust enough to fully investigate higher order variations. Indications of the influence of the lower mantle on outer core behavior and the suggestion of orbital periodicities in magnetic field variations are only two possibilities that could be investigated with future modeling. Efforts over the past few years have increased the number of high precision paleomagnetic field studies with particular emphasis on high latitudes and Southern Hemisphere locations. Recent considerations of the number of lava flows needed to assess the TAF implies that regional studies are of considerable importance. Additionally, the need to include paleointensity measurements along with the more common directional measurements is vital for future models. Brown proposes that studying paleosecular variation using both directional and intensity data over a region in southern Patagonia (46 degrees S - 52 degrees S) will provide important additional data for TAF modeling. Several hundred sites will be collected in a region where young lava flows, < 5 myr, are extensive. Different views of field dispersion exist in this area; more extensive sampling over a wider area will be able to further investigate this discrepancy. Broader impacts of this research will include the education and training of graduate and undergraduate students as they participate in fieldwork, laboratory work, interpretations and presentation of results. In addition, this work will be incorporated into a dynamic digital map (DDM) for use by the wider geoscience community. DDMs are part of the Digital Library for Earth Sciences Education (DLESE) project, and are an established way to make geologic information tied to geologic maps available over the WEB. The results can be accessed by students and researchers at various levels but the PI will put particular emphasis on undergraduate geoscience classes wishing to investigate tectonics, volcanism and paleomagnetism in southern Patagonia.
