Integrated rock magnetic, paleomagnetic and geochemical studies of overpressured sediments from the Gulf of Mexico, Brazos-Trinity #4 and Ursa Basin, IODP Leg 308

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During IODP Leg 308 ( Overpressure and Fluid Flow Processes in the Deepwater Gulf of Mexico: Slope Stability, Seeps and Shallow Water Flow ) four late Quaternary sediment series were recovered in the Brazos-Trinity #4 minibasin and in the Ursa region of the northern Gulf of Mexico to test multidimensional flow models and deformation processes in passive margin settings. In this project, we plan to combine available and new rock magnetic and geochemical data to examine low-permeability mudstones overlying overpressured aquifers to track fluid flow pathways and precipitation horizons related to changes in the sedimentary milieu. We also use rock magnetic proxies to describe variations in continental input (iron oxides) and the stage of early diagenetic alteration (iron sulfides). Magnetite and greigite have been identified by pilot rock magnetic and SEM studies. To understand the time frame of such processes, we will refine the preliminary bio- and magnetostratigraphic Brazos-Trinity age model and link it to the Ursa drill sites using rock magnetic, physical property and color data for cyclostratigraphic correlation. This research concept is planned to be carried out by Christine Franke in continuation and consequential scientific exploitation of her shipboard work.